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The Brazilian Society of Cardiology and Brazilian Society of Exercise and Sports Medicine Updated Guidelines for Sports and Exercise Cardiology - 2019
research-article
Nabil Ghorayeb
1
,
2
,
3
,
4 ,
Ricardo Stein
5
,
6
,
7 ,
Daniel Jogaib Daher
2 ,
Anderson Donelli da Silveira
5
,
6
,
7 ,
Luiz Eduardo Fonteles Ritt
8
,
9 ,
Daniel Fernando Pellegrino dos Santos
2 ,
Ana Paula Rennó Sierra
10 ,
Artur Haddad Herdy
11
,
12 ,
Claúdio Gil Soares de Araújo
13 ,
Cléa Simone Sabino de Souza Colombo
2
,
14 ,
Daniel Arkader Kopiler
15
,
16 ,
Filipe Ferrari Ribeiro de Lacerda
5 ,
José Kawazoe Lazzoli
15
,
17 ,
Luciana Diniz Nagem Janot de Matos
18 ,
Marcelo Bichels Leitão
15 ,
Ricardo Contesini Francisco
1
,
2 ,
Rodrigo Otávio Bougleux Alô
1
,
19 ,
Sérgio Timerman
20
,
21 ,
Tales de Carvalho
12
,
22
,
23 ,
Thiago Ghorayeb Garcia
1
,
2
March 2019
There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Declaration of potential conflict of interest
of authors/collaborators of The Brazilian Society of Cardiology and
Brazilian Society of Exercise and Sports Medicine Updated Guidelines for
Sports and Exercise Cardiology - 2019
If the last three years the author/developer
of the Guidelines:
Names Members of the Policy
Participated in clinical studies and/or experimental
trials supported by pharmaceutical or equipment related to the guideline
in question
Has spoken at events or activities sponsored by industry
related to the guideline in question
It was (is) advisory board member or director of a
pharmaceutical or equipment
Committees participated in completion of research
sponsored by industry
Personal or institutional aid received from industry
Produced scientific papers in journals sponsored by
industry
It shares the industry
Ana Paula Rennó Sierra
No
No
No
No
No
No
No
Anderson Donelli da Silveira
No
No
No
No
No
No
No
Artur Haddad Herdy
No
No
No
No
No
No
No
Claúdio Gil Soares de Araújo
No
No
No
No
Inbramed
No
No
Cléa Simone Sabino de Souza Colombo
No
No
No
No
Inbramed
No
No
Daniel Fernando Pellegrino dos Santos
No
No
No
No
No
No
No
Daniel Jogaib Daher
No
No
No
No
No
No
No
Daniel Arkader Kopiler
No
No
No
No
No
No
No
Filipe Ferrari Ribeiro de Lacerda
No
No
No
No
No
No
No
José Kawazoe Lazzoli
No
No
No
No
No
No
No
Luciana Diniz Nagem Janot de Matos
No
No
No
No
No
No
No
Luiz Eduardo Fonteles Ritt
No
No
No
No
No
No
No
Marcelo Bichels Leitão
No
No
No
No
No
No
No
Nabil Ghorayeb
No
No
No
No
No
No
No
Ricardo Contesini Francisco
No
No
No
No
No
No
No
Ricardo Stein
No
TEB, Inbramed, Health in Code
No
No
TEB, Inbramed, Health in Code
No
No
Rodrigo Otávio Bougleux Alô
No
No
No
No
No
No
No
Sérgio Timerman
No
No
No
No
No
No
No
Tales de Carvalho
UDESC
No
No
No
No
No
No
Thiago Ghorayeb Garcia
No
No
No
No
No
No
No
Content
1. Presentation and
Introduction.......................................................330
2. Pre-Participation
Screening...........................................................330
2.1.
Introduction.......................................................................................330
2.2. Anamnesis and Physical
Examination...............................................331
2.3. Complementary
Exams.....................................................................331
2.3.1. Twelve-Lead
Electrocardiogram....................................................332
2.3.1.1.
Introduction...............................................................................332
2.3.1.2.
Method.......................................................................................332
2.3.1.3.
Analysis......................................................................................332
2.3.1.4.
Changes......................................................................................332
2.3.2. Electrocardiogram: Physiological Changes vs. Changes Suggestive of Heart
Disease......................................................................................332
2.3.3. Exercise Stress
Testing...................................................................334
2.3.3.1. Variables to be Evaluated in an Exercise Stress Testing.............334
2.3.3.1.1. Functional
Capacity.................................................................334
2.3.3.1.2. Chest
Pain...............................................................................334
2.3.3.1.3. ST-T
Segment...........................................................................334
2.3.3.2. Blood
Pressure...........................................................................334
2.3.3.3. Heart
Rate..................................................................................335
2.3.3.4. Cardiac
Arrhythmias..................................................................335
2.3.4. Cardiopulmonary Exercise
Testing................................................335
2.3.5.
Echocardiogram................................................................................
336
2.3.6.
Recommendations.........................................................................336
2.3.7. Other Complementary
Tests.........................................................336
2.3.8. Final
Recommendations................................................................337
3. Genetic Evaluation and
Exercise...................................................337
3.1. Positive Genotype and Negative
Phenotype.......................................337
4. Individuals with Cardiomyopathies and Myocarditis..................338
4.1. Hypertrophic
Cardiomyopathy...........................................................338
4.1.1. Genetics and Hypertrophic Cardiomyopathy...............................339
4.1.2. Complementary Exams in Hypertrophic Cardiomyopathy...........339
4.1.2.1.
Electrocardiogram......................................................................339
4.1.2.2.
Echocardiogram.........................................................................339
4.1.2.2.1. Transthoracic Doppler
Echocardiogram..................................339
4.1.2.2.2. Transesophageal Doppler Echocardiogram............................340
4.1.2.3. Cardiac Magnetic Resonance
Imaging.......................................340
4.1.2.4. Exercise Tests and Hypertrophic Cardiomyopathy....................340
4.1.2.4.1. Exercise Testing Recommendations for Patients with Hypertrophic
Cardiomyopathy...............................................................340
4.1.2.4.2. The Role of Maximal Cardiopulmonary Exercise Testing in Hypertrophic
Cardiomyopathy...............................................................341
4.1.3. Sports and Hypertrophic
Cardiomyopathy...................................341
4.2. Arrhythmogenic Right Ventricular
Dysplasia......................................341
4.2.1. Diagnosis and Management of Athletes with Suspected Arrhythmogenic Right
Ventricular Dysplasia..........................................342
4.2.1.1.
Echocardiogram.........................................................................342
4.2.1.2. Cardiac Magnetic Resonance
Imaging.......................................342
4.3.
Myocarditis........................................................................................342
4.3.1. Recommendations for Athletes with Myocarditis.........................342
4.4. Dilated
Cardiomyopathy....................................................................343
4.4.1. Complementary Exams for Dilated Cardiomyopathy...................343
4.4.1.1. Exercise Stress Testing and Cardiopulmonary Exercise Testing....343
4.4.1.2.
Echocardiogram.........................................................................343
4.4.1.3. Cardiac Magnetic Resonance
Imaging.......................................343
4.4.2. Sports and Dilated
Cardiomyopathy.............................................343
4.4.2.1. Recommendations for Athletes Diagnosed with Dilated
Cardiomyopathy......................................................................................343
4.5. Non-Compacted
Cardiomyopathy......................................................344
4.5.1. Sports and Non-Compacted Cardiomyopathy..............................344
4.5.1.1. Recommendations for Athletes Diagnosed with Non-Compacted
Cardiomyopathy......................................................................................344
4.6. Chagas
Disease.................................................................................344
5.
Channelopathies..............................................................................345
5.1.
Introduction.......................................................................................345
5.2. Long QT
Syndrome............................................................................345
5.2.1. Genetic Alterations in Long QT
Syndrome....................................345
5.2.2. Risk Stratification in Long QT
Syndrome......................................345
5.2.3. Recommendations for Athletes with Long QT Syndrome.............345
5.3. Short QT Syndrome
..........................................................................346
5.4. Brugada
Syndrome............................................................................347
5.5. Catecholaminergic Polymorphic Ventricular Tachycardia...................347
6. Athletes with Valvular Heart
Disease...........................................348
6.1.
Introduction.......................................................................................348
6.2. Aortic Valve
Disease..........................................................................348
6.2.1. Aortic
Stenosis...............................................................................348
6.2.1.1. Recommendations and Evidence
Level......................................349
6.2.2. Aortic
Regurgitation......................................................................349
6.2.2.1. Recommendations and Evidence
Level......................................349
6.2.3. Bicuspid Aortic
Valve.....................................................................350
6.2.3.1.
Recommendations......................................................................350
6.3. Mitral Valve
Disease..........................................................................350
6.3.1. Mitral
Stenosis...............................................................................350
6.3.1.1. Recommendations and Evidence
Level......................................350
6.3.2. Mitral
Regurgitation......................................................................351
6.3.2.1. Recommendations and Evidence
Level......................................351
6.3.3. Mitral-Valve
Prolapse....................................................................351
6.3.3.1.
Recommendations......................................................................352
6.3.4. Tricuspid
Stenosis..........................................................................352
6.3.4.1.
Recommendations......................................................................352
6.3.5. Tricuspid
Regurgitation.................................................................352
6.3.5.1.
Recommendations......................................................................353
6.3.6. Multivalvular Heart
Disease..........................................................353
6.3.6.1.
Recommendations......................................................................353
6.4. Sports After Valve
Surgery.................................................................353
6.4.1. Recommendations and Evidence
Level.........................................353
6.4.2. Transcatheter Aortic Valve
Implantation.......................................353
7. Athlete's Heart Syndrome in
Women...........................................353
7.1.
Introduction.......................................................................................353
7.2. Complementary
Exams.....................................................................354
7.2.1. Twelve-Lead
Electrocardiogram....................................................354
7.2.1.1. Electrocardiogram: Physiological Changes vs. Changes Suggestive of Heart
Disease......................................................................................354
7.3.
Echocardiogram................................................................................354
7.4. Exercise
Testing.................................................................................354
7.5. Sudden
Death....................................................................................355
8. Basic Life Support for
Athletes......................................................355
8.1. Sudden Death among
Athletes..........................................................355
8.2. Initial Care for
Athletes......................................................................355
8.3. Special Aspects in Preventing Exercise/Sports-Related Sudden
Death.......................................................................................................356
8.3.1. Doping: Illicit Substances in
Sports..............................................356
8.3.1.1. Anabolic
Steroids.......................................................................356
8.3.1.2.
Ephedrine...................................................................................356
8.3.1.3.
Amphetamines...........................................................................356
8.3.1.4.
Cocaine.......................................................................................357
8.3.1.5.
Ecstasy........................................................................................357
8.4. Evaluating Athletes and the Organization and Planning of Emergency
Care......................................................................................357
8.4.1. Aspects Related to the
Athlete.......................................................357
8.4.1.1. Pre-Participation
Screening........................................................357
8.4.1.2. Regarding the Athlete's
Preparation..........................................357
8.4.2. Aspects Related to Training Venues and Competition..................357
8.4.2.1. Emergency Care and Medical Contingency Planning.................357
8.4.2.2. Automatic External
Defibrillators...............................................357
References............................................................................................358
1. Presentation and Introduction
Movement is a part of daily life for humans, who must get from one place to another,
pick up and carry things, relate to others or simply move for the pleasure of
moving. Caspersen et al.'s,
1
classic definition (1985) will be used in this Update, in which all body movement
produced by the skeletal muscles that results in energy expenditure is considered
physical activity. Physical exercise can be conceptualized as a special type of
physical activity that is planned, structured and repetitive, whose ultimate or
intermediate goal is to maintain or improve health, physical conditioning, body
aesthetics or performance in competition.
1
Although sports are often associated with leisure, they can also be a person's main
activity: individuals can characterize themselves as professional athletes when it
becomes their means of livelihood or an important source of income. Recently, the
concept of athlete was formally defined as someone who simultaneously meets the
following four criteria: (a) trains to improve sports performance or results; (b)
actively participates in sports competitions; (c) is formally recognized at a local,
regional or national level; (d) regards competition as a main activity (way of life)
or as a focus of personal interest, devoting several hours to training every day or
most days, exceeding the time allocated to other professional or leisure
activities.
2
Those who
exercise regularly and but only compete occasionally, such as in marathons or other
mass sports events, should be called amateur athletes.
2
Thus, although primarily directed to professional
athletes, many aspects covered in this Update also apply to amateurs and some apply
to non-athletes who exercise regularly.
These updated guidelines for sports and exercise cardiology will address the
following topics: pre-participation screening, structural and non-structural heart
diseases, genetic aspects of these pathologies, valvular disease, the hearts of
female athletes, as well as basic life support for athletes. Some topics in the 2013
Guidelines
3
will be covered
in future publications or can be consulted in other specific Guidelines.
In summary, this document serves as a de facto update for this field of knowledge
and
can be applied in clinical practice.
2. Pre-Participation Screening
2.1. Introduction
Clinical pre-participation screening (PPS) for sports activities should be
understood as a standardized systematic medical evaluation that can cover a
broad population of professional and amateur athletes before participating in
regular moderate-to-intense exercise. Its purpose is to identify cardiovascular
diseases that are incompatible with certain types of exercise. The main
objective of this screening, which is conducted prior to initiating training and
periodically afterwards, is the prevention of cardiovascular diseases and the
early detection of diseases that cause sudden cardiac death (SD). This can be
achieved by temporarily or permanently suspending the exercise or by treating
the potentially fatal conditions that it could trigger. The American Heart
Association,
4
the
European Society of Cardiology
5
and the Brazilian Society of Exercise and Sports Medicine
3
recommend PPS for all
professional athletes. PPS can also be recommended for correctly prescribing
moderate-to-high intensity exercise for non-professionals.
Corrado et al.
6
demonstrated the
importance of PPS for preventing SD. Over a 26-year period during which PPS was
introduced as a federal law in Italy (1979-2004), the incidence of SD in
screened athletes was reduced by 89%: from 3.6 per 100,000 person-years in
1979-1980 to 0.4 per 100,000 person-years in 2003-2004. At present, one of the
main issues in PPS is cost-effectiveness. Some societies, such as the American
Heart Association, advocate screening with only a questionnaire and a physical
examination, believing that the financial and psychological costs associated
with false positive results in complementary examinations, such as
electrocardiograms (ECG), do not justify the potential benefits.
4
However, the European Society of
Cardiology and numerous sporting associations (e.g., FIFA, the NBA), support the
use of resting ECG, since it has been shown to affect the incidence of SD among
athletes.
7
,
8
Although we do not have randomized studies comparing the two models of
evaluation, we suggest that PPS for professional athletes should include 12-lead
resting ECG, since, first, it helps guarantee their safety and, second, the
investments involved in their training.
9
-
11
These issues will be addressed in this document, which
aims to establish norms for PPS in our country.
For didactic purposes, as well as due to clinical, physiological, and
epidemiological differences, we have chosen to divide PPS candidates into two
groups: amateur athletes and professional athletes. When considering various
aspects of exercise, such as intensity, training frequency and volume, a zone of
intersection will always exist between these groups. Nevertheless, the medical
evaluator's good judgment and individual experience will be fundamental in
choosing a way forward in these cases. In light of such divisions, it is of
fundamental importance to understand the distinction this Guideline determines
between amateur and professional athletes:
Amateurs: adults who participate in regular, moderate-to-high intensity sports
activities who occasionally compete, although without professional ties to the
sport.
Professionals:
2
Individuals who train to improve their sports performance
Individuals who actively participate in competitions
Individuals who train and compete as their main activity or as a
focus of personal interest. They devote a number of hours on most
days to training, exceeding the time spent in other professional or
leisure activities.
However, professional athletes can also be classified according to age:
Young athletes - 12 to 17 years.
Adult athletes - 18 to 35 years.
Master athletes - 35 years or older.
2.2. Anamnesis and Physical Examination
Ideally, all candidates for moderate-to-high intensity exercise should undergo
PPS, which can identify risk factors and signs and symptoms suggestive of
cardiovascular, pulmonary, metabolic or locomotor disorders.
12
-
14
In anamnesis, issues related
to exercise, including family history of disease or sports-related
cardiovascular events, should be prioritized. However, a detailed investigation
of family history with respect to heart disease or other SD-related diseases
must be performed. To do this, adequate knowledge of these medical conditions
and a cardiological approach are important.
10
,
15
,
16
In PPS it should be considered that cardiac adaptations to physical exercise are
frequency, intensity, and duration dependent and vary among different sports and
training systems, as well as among individuals.
17
Due to the latter aspect, different
adaptations can be found in individuals involved in similar physical activities.
It should be pointed out that the modifications involved in what is referred to
as "athlete's heart syndrome" should initially be considered as normal
physiological adaptations to exercise, of a transient nature and without
negative repercussions on an individual's health.
18
The Physical Activity Readiness Questionnaire can be applied systematically
during anamnesis. This questionnaire, developed in Canada, should be combined
with basic questions asked by a physician (Table
1) about cases of SD or inherited heart diseases, family history of
sickle cell disease or other hemoglobinopathies, as well as the patient's
origin. Determining the patient's origin is important, since certain regions
have endemic diseases, such Chagas' disease, or have a higher prevalence of
congenital diseases, such as the Veneto region of Italy, where there is a higher
prevalence of arrhythmogenic right ventricular dysplasia (ARVD).
19
,
20
Particular care should be
taken when obtaining information about licit or illicit drug use that could be
considered as doping or that could be harmful to health (i.e., which could cause
SD or other undesirable events).
21
,
22
Important symptoms include: palpitations, syncope, chest
pain or discomfort, exertional dyspnea, dizziness/asthenia, or any other symptom
triggered by exercise. Accurate sensitivity is needed to determine whether
mentioned symptoms indicate a disease state or are merely the consequence of
more intense training or competition. For both amateur and professional
athletes, if syncope occurs during exercise rather than post-effort, a detailed
investigation should be conducted to discard a primary arrhythmic
event.
23
Table 1
Details to be included in a personal and family history assessment for
athletes
Has any doctor ever told you that you have a heart
problem?
Have there been cases of sudden death or heart
disease in your family?
Precordial pain or discomfort on exertion or at
rest
Do you feel chest pain when exercise?
Pre-syncope or syncope, especially if related to
exertion
Do you lose your balance due to dizziness and/or
loss of consciousness? Are there cases of heart disease,
sudden death before age 50 or cardiac arrhythmias In your
family?
Arrhythmias
Observe palpitations (skipped beats or heart
racing)
Previously diagnosed pathologies
Previous history of heart murmur Previous
history of hypertension Previous history of metabolic
disease Use of performance enhancing substances/ use of
any medication Live/lived in an area with endemic Chagas
disease
Do you have any bone or joint problems that could
be made worse by physical activity?
Do you currently take some type of
medication? Question directly about anti-hypertensive,
NSAID, anabolics, illicit drugs, and alcohol consumption
Is there any other reason why you should not
perform physical activity?
Family members with genetic diseases;
hypertrophic cardiomyopathy, dilated cardiomyopathy,
channelopathies, arrhythmias, Marfan syndrome
NSAID: nonsteroidal anti-inflammatory drug.
The physical examination should include inspection for certain clinical
conditions, such as anemia, posture changes, infectious foci (e.g., dental),
severe systemic or infectious diseases, bronchial asthma, obesity, diabetes
mellitus, systemic arterial hypertension, and changes in pulmonary or
cardiovascular auscultation. A search for signs related to possible
cardiovascular disease should be prioritized, such as: heart murmur, third and
fourth heart sounds, valve clicks, pulse changes in the upper and lower limbs,
signs of Marfan syndrome or other aortic diseases (e.g., Loeys-Dietz syndrome),
as well as adequate blood pressure (BP) in both arms at the first
evaluation.
14
,
24
,
25
Recommendation for anamnesis and physical
examination
Recommendation grade
Evidence level
Amateur athletes
I
C
Professional athletes
I
A
2.3. Complementary Exams
Laboratory tests, in principle, are unnecessary: requests for them should be
based on clinical data, especially cardiocirculatory issues. Routine laboratory
tests include: complete blood count, fasting glucose, urea, creatinine, sodium
and potassium, complete lipid profile, uric acid, glutamic-oxalacetic
transaminase, glutamic-pyruvic transaminase, gamma-glutamyl transpeptidase,
bilirubin, prothrombin time/international normalized ratio, and common urine
testing.
Recommendation grade: I.
Evidence level: B.
For individuals who exercise or compete at altitudes over 2,000 meters, it is
important to perform hemoglobin electrophoresis to rule out the possibility of
hemoglobinopathies (e.g., sickle cell anemia). In our country, especially in
regions of higher incidence, serology for Chagas' disease may also be
recommended.
3
Chest
radiography may also be requested in many cases.
2.3.1. Resting 12-Lead Electrocardiogram
2.3.1.1. Introduction
Use of this examination in groups of younger athletes is controversial.
Although the American Heart Association (American College of
Cardiology/American College of Sports Medicine) does not include ECG in
PPS, the European Society of Cardiology, in addition to numerous sports
organizations, recommend it.
4
,
5
For master athletes, resting ECG is mandatory,
since older adults have a higher prevalence of cardiovascular diseases,
especially coronary artery disease (CAD).
26
,
27
2.3.1.2. Method
Conventional 12-lead ECG should be performed with the individual in the
supine position, recorded at a velocity of 25 mm/s and ideally obtained
24 hours after the last sporting activity. At least 5 minutes of rest is
recommended before the examination.
3
,
28
2.3.1.3. Analysis
Since there are peculiarities among the resting ECG results of athletes,
examinations should be interpreted by physicians with experience in the
area. This recommendation is important, because it will prevent common
alterations of the athlete's heart from being confused with heart
disease. However, in most countries medical knowledge regarding the
interpretation of athletes' ECG is still limited, which prohibits
broader application of this method.
29
2.3.1.4. Changes
Regular intense exercise can cause physiological changes to the heart at
structural, functional and electrical levels. The ECG findings of more
than 80% of high-performance athletes reflect exercise-induced cardiac
adaptations as a result of intrinsic changes in automaticity and
atrioventricular conduction,
30
as well as of increased vagal tone and cardiac
remodeling.
Due to the establishment of criteria that allow a distinction between
heart diseases and athlete's heart syndrome, interpretations of
athletes' ECG are becoming more uniform.
28
,
31
It is understood that the false
positives associated with athletes' ECG depend on the criteria used in
their interpretation, as well as our current understanding of variations
of normality. Thus, new criteria represent a major effort to refine the
analysis and interpretation of ECG, making it more specific without
losing sensitivity. Variations in the prevalence of these criteria are
related to gender (higher in males), age (genetic/congenital diseases in
young athletes and CAD in master athletes), ethnicity (black athletes
have more left ventricular overload and repolarization changes than
athletes of other races), training level (variation is more frequent in
professional athletes than amateurs) and type of sport (predominantly
regarding the dynamic component).
28
It can be especially difficult to differentiate
between physiological and pathological adaptations in black athletes,
since they have a tendency to develop more hypertrophy in response to
exercise than whites. We should also point out that more than 10% of
black athletes may have a wall thickness > 12 mm in the
echocardiogram.
32
Failure to distinguish between the physiological and the pathological can
have harmful consequences. Athletes can be unnecessarily disqualified
from competition due to ECG changes that could be considered normal.
Likewise, they may undergo unnecessary examinations, which greatly
increase their costs. On the other hand, signs of life-threatening
cardiovascular disease may be erroneously interpreted as normal variants
of an athlete's ECG, which could put the individual at risk of SD.
Changes in the athlete's ECG can be divided into two groups: common
and/or related to training; or uncommon and/or suggestive of heart
disease (Table 2). ECG is most
useful when performed as part of PPS, when it can identify unexpected
changes, such as previous myocardial infarction (in older age groups),
arrhythmias, conduction disorders, etc. An ECG may also help diagnose
less prevalent diseases, such as hypertrophic cardiomyopathy (HCM), long
QT syndrome, short QT syndrome, Brugada syndrome, Wolff-Parkinson-White
syndrome (or other pre-excitation syndrome), in addition to
arrythmogenic right ventricular dysplasia (ARVD). A 12-lead ECG may also
facilitate assessment of significant atrioventricular and
intraventricular conduction and rhythm disturbances. It can also detect
ST-segment changes, such as early repolarization, T-wave inversion in
precordial and/or peripheral leads, and voltage criteria suggestive of
left ventricular hypertrophy (LVH).
28
,
31
Table 2
Electrocardiogram: changes due to exercise vs. changes suggestive
of heart disease
Physiological ECG findings in athletes
Abnormal ECG findings in athletes
Sinus Bradycardia (HR > 30bpm)
T-wave inversion > 1 mm in 2 or more
leads (except DIII, aVR and V1)
Sinus arrhythmia
ST-segment depression> 0.5 mm in 2 or
more leads
Ectopic atrial rhythm
Pathological Q waves > 3 mm or > 40
ms in 2 or more leads (except DIII and aVR)
Junctional escape rhythm
Complete left bundle branch block
1st degree BAV (PR interval >
200 ms)
Nonspecific conduction delay with QRS
> 140 ms
2nd degree AVB Mobitz I
(Wenckebach)
Deviation of the electrical axis from -
30° to 90°
Incomplete right bundle branch block
Left atrial overload
Isolated QRS voltage criterion
for LVH
Right ventricular hypertrophy pattern
with RV1 + SV5 > 10.5 mm and axis deviation >
120°
Ventricular pre-excitation
Early repolarization
QT interval > 470 ms in men and >
480 ms in women
ST-segment elevation
accompanied by T-wave inversion in leads V1 to V4 in
Black athletes
QT interval < 320 ms
Brugada pattern
Sinus bradycardia < 30 bpm or sinus
pauses > 3 s
Atrial tachyarrhythmia
Ventricular extrasystoles with 2 or more
10-second ECG episodes
Paired ventricular extrasystoles and
NSVT
AVB: atrioventricular block; BPM: beats per minute; ECG:
electrocardiogram; HR: heart rate; LVH: left ventricular
hypertrophy; NSVT: nonsustained ventricular tachycardia.
There may be variations in the prevalence of EGC changes, which are more
frequent in men than women. In relation to age, we found a higher
frequency of inverted T-waves in precordial and/or peripheral leads in
master athletes and older adults, as well as criteria for LVH, in
addition to conduction disturbances (Table 3). There are also significant variations
in 12-lead
ECG results in different types of sports.
Table 3
Different types of electrocardiographic abnormalities in relation
to age found in an unselected European population of 32,652
subjects who underwent sports pre-participation screening
< 20 years
(n = 2.430)
%
20-29 years (n = 2.430) %
> 30 years (n = 2.430) %
Incomplete RBBB, increased PR interval,
early repolarization pattern
73.1
37.9
30.1
Inverted T-waves
9.5
38.6
37.9
R/S wave voltage increase
3.1
4.6
7.2
RBBB
10.9
12.1
10.9
LAHB, LBBB
2.1
5.7
13.3
Pre-excitation pattern
1.3
1.1
0.6
LAHB: left anterior hemiblock; RBBD: right bundle branch
block; LBBB: left bundle branch block. Adapted from
Pelliccia et al.
73
Recommendation grade: I.
Evidence level: A.
2.3.2. Electrocardiogram: Physiological Changes vs. Changes Suggestive of
Heart Disease
Athletes frequently show ECG changes (up to 80% in some series), including:
bradycardia/sinus arrhythmia (13% to 69%), first degree atrioventricular
block (35%), and early repolarization (50% to 80%). Such findings are
usually due to physiological adaptations related to athlete's heart
syndrome.
33
Athletes may also present voltage criteria for LVH, which reflects
remodeling of this cavity, although without pathological Q-waves, electrical
axis deviation, atrial overload or repolarization changes.
31
,
32
These physiological
changes in ECG should be clearly separated from patterns suggestive of heart
disease, which can be recognized by repolarization changes, pathological Q
waves, marked intraventricular conduction defects, pre-excitation, short or
long QT intervals, and Brugada syndrome. These findings are rare (less than
5%) but may express some cardiomyopathy or channelopathy that could
predispose the athlete to SD.
33
Another important point concerns atrial dilation
(resulting from regular training) to meet increased cardiac demand during
exercise, although this is not fully understood. Nevertheless, despite this
dilation, atrial function seems to be preserved in athletes, but not in
patients with structural heart disease.
34
Other less common findings that can be identified in athletes are sinus
pauses < 3 s (mainly during sleep) and second-degree bicuspid aortic
valve (BAV) type I (Wenckebach). Such findings generally disappear during
effort and with the administration of substances. Changes that can be
considered cardiac adaptations to physical exertion should not cause alarm,
and participation in competitive sports should not be prohibited without
further evaluation. On the other hand, findings suggestive of heart disease,
even if asymptomatic, should be investigated, especially in the absence of a
positive family history or the presence of abnormal findings during physical
examination.
35
,
36
Recommendation grade: I.
Evidence level: A.
2.3.3. Exercise Stress Testing
As part of a strategy for early cardiovascular disease identification, an
exercise stress testing can be recommended for the initial evaluation of
amateur or professional athletes of any age group. This test can contribute
to the prognosis of asymptomatic patients or when there are symptoms
potentially indicative of some pathological condition.
37
,
38
Its may also be used to
evaluate cardiorespiratory fitness during training for certain sports,
especially those with a predominantly aerobic component.
39
,
40
Asymptomatic individuals with no cardiovascular risk factors can be cleared
without this examination. However, an exercise stress testing may be
recommended in other conditions.
41
After 35 years of age, CAD is the main cause of
mortality. An exercise stress testing is recommended for individuals in this
age range, mainly to identify myocardial ischemia, since the results can
indicate the probable presence of the disease. In asymptomatic individuals,
and even in those with known CAD, exercise stress testing is used for
prescribing an adequate level of physical activity.
Changes in resting ECG, often due to physiological LVH, reduce the method's
accuracy for diagnosing myocardial ischemia. Simultaneous analysis of other
examination variables contributes to a more global assessment.
42
When a patient mentions
having palpitations during physical activity, this should be investigated
with an exercise stress testing to reproduce the conditions of the complaint
in a controlled environment.
2.3.3.1. Variables to be Evaluated in an Exercise Stress
Testing
2.3.3.1.1. Functional Capacity
Low functional capacity indicates a poor prognosis. A number of
observational studies have demonstrated an inverse association
between the metabolic equivalents reached in the exercise stress
testing and mortality.
43
-
45
When an individual's functional capacity is
low compared to predicted values for his or her gender and age
group, additional investigation may be necessary.
46
2.3.3.1.2. Chest Pain
An exercise stress testing can reproduce the conditions of chest pain
or discomfort during exercise and allows a probable diagnosis of
myocardial ischemia due to CAD, which should lead to further
investigation and suspension of training. When an exercise stress
testing leads to non-ischemic pain similar to that which motivated
the test, but there are no changes in any of the test variables, the
probability of CAD is low and the athlete can return to
competition.
47
On the other hand, chest pain characteristic of
angina, even if unaccompanied by ST-segment changes, is usually
associated with a poor prognosis. Proper interpretation of an
exercise stress testing requires prior knowledge of normal findings
for young athletes. Determining whether ST-segment depression in
master athletes is related to CAD can be challenging. The
possibility of a false positive result related to LVH cannot be
ruled out, but ischemia of atherosclerotic origin should always be
discarded. Additional investigation may be required before returning
to practice and competition.
48
2.3.3.1.3. ST-T Segment
ST-segment depression > 1 mm is suggestive of CAD, especially when
in a horizontal or descending pattern. Such alterations have higher
values when occurring concomitantly with chest pain or other
manifestations that contribute to a diagnosis of myocardial
ischemia.
49
ST-segment elevation ≥ 1 mm at 60 ms
after J-point, when not observed in a Q-wave area (inactive zone),
is very suggestive of subepicardial (or transmural)
injury,
50
indicates ischemia and must be managed as such.
In asymptomatic athletes, when ST alterations occur during an
exercise stress testing, even if unaccompanied by chest pain, or
when they occur with high double product values and high exercise
capacity, especially if associated with frequent cardiac
arrhythmias, training should be suspended (temporarily or not). In
such cases, it is of fundamental importance to continue
investigation into cardiovascular disease. Such an approach is based
on the increased cardiovascular demand and increased risk of events
during exercise, especially in individuals over 35 years of age or
when one or more CAD risk factors are present.
ST-segment analysis should consider:
• Morphological characteristics, i.e., descending
is more serious than horizontal, which is more serious
than slow ascending.
51
• Early onset during exercise and persistent
changes late in the recovery phase indicate greater risk
and severity.
52
• ST-segment depression greater than 10% in
relation to the immediately preceding R-wave amplitude.
This adjustment in ST-segment evaluation should be
considered due to recurring high-amplitude R-waves,
which can express physiological LVH.
53
Furthermore, regarding the ventricular repolarization phase, it is
important to point out that when starting from an altered ECG,
normalization during exercise can indicate a good prognosis (if not
accompanied by symptoms).
54
,
55
2.3.3.2. Blood Pressure
Excessively high BP during an exercise stress testing in patients who
have not been diagnosed with hypertension and who have normal resting
levels could be a warning sign, because there is a significantly greater
risk of developing hypertension in subsequent years. In patients with
newly diagnosed hypertension, laboratory investigation and treatment
should begin immediately. However, if there is a progressive decrease in
systolic BP during an exercise stress testing, especially when it falls
below the pre-effort value, subsequent investigation for heart disease
should be carried out, especially in cases of stress-induced systolic
dysfunction.
2.3.3.3. Heart Rate
Chronotropic incompetence indicates a poor prognosis and has been
associated with endothelial dysfunction, altered autonomic modulation,
elevated inflammatory markers and CAD. An inadequate HR response can be
considered as the inability to achieve 85% of the estimated maximum HR.
The following equation can be used to predict maximum HR: 208 - (age
× 0.70). A chronotropic index < 80% is another way to identify
chronotropic incompetence, which has prognostic value. It is obtained by
the following ratio: (HR reserve obtained/estimated HR reserve) ×
100.
56
Vagal modulation of HR can be inferred from HR reduction in the first
minute of recovery in relation to HR at peak exertion. This observation
was initially identified when comparing athletes with heart failure (HF)
patients.
57
,
58
Reductions ≤ 12 beats per minute have
been associated with higher mortality rates.
59
2.3.3.4. Cardiac Arrhythmias
Less complex cardiac arrhythmias, such as occasional ventricular
extrasystoles during an exercise stress testing, often express an
increase in sympathetic autonomic modulation due to graduated exercise.
Such conditions alone, without other alterations, do not justify
limiting the activity of asymptomatic individuals, nor do they require
further investigation. Symptomatic or asymptomatic patients who develop
complex ventricular arrhythmias, such as ventricular tachycardia
(whether sustained or not), must be investigated before they return to
training.
For mild-to-moderate intensity leisure activities in asymptomatic
individuals with a cardiovascular risk factor: perform an exercise
stress testing at the beginning of participation.
Recommendation grade: III.
Evidence level: C.
For amateur athletes participating in high-intensity sports and
competition: perform exercise stress testing at the beginning of
training.
Recommendation grade: IIa.
Evidence level: A.
For professional athletes participating in high-intensity athletic
activity and competition: perform an exercise stress testing at the
beginning of the season.
Recommendation grade: I.
Evidence level: C.
Any time:
When a patient refers to chest pain or discomfort, fatigue or dyspnea of
unknown cause, palpitations, or when previously non-existent
arrhythmias, exercise-related pre-syncope or syncope or elevated resting
BP (with or without compromise a target organ) are identified: perform
an exercise stress testing.
Recommendation grade: I.
Evidence level: A.
2.3.4. Cardiopulmonary Exercise Testing
For a long time (including in Brazil), athletes and individuals participating
in high-performance activities have undergone cardiopulmonary exercise
testing (CPET) to evaluate performance and prescribe aerobic
training.
60
As
described in Table 4, CPET differs
from an exercise stress testing by adding measures and analyses of expired
gases.
61
Unlike in
exercise tests for clinical diagnosis, when CPET is performed in apparently
healthy athletes BP is often not measured and even ECG is often not
performed, and HR is obtained by frequency meter. With so much equipment
available (e.g., in laboratories, clinics, hospitals, clubs and sports
centers) to perform these measures, there is little sense in evaluating an
athlete's aerobic condition through a exercise stress testing, which has an
error rate of approximately 20% when estimates based on formulas developed
for clinical protocols involving treadmills or cycle ergometers are
used.
Table 4
Main differences between exercise stress testing and cardiopulmonary
exercise testing
Exercise testing
Variable
Exercise stress testing
Cardiopulmonary exercise testing
Functional capacity
Measured
Measured
Maximum aerobic power
Estimated
Measured
Anaerobic threshold
Undetermined
Determined
V/Q Ratio
Not evaluated
Evaluated
Inotropic response
Limited evaluation
Excellent evaluation
Mechanical Efficiency
Presumed
Measured
Protocol
More dependent
Less dependent
True maximum cardiorespiratory capacity
Presumed
Probable/identified
Etiology of dyspnea
Unidentified
Probable/identified
V/Q ratio: ventilation/perfusion ratio
In certain clinical settings and for certain groups of athletes, including a
CPET in PPS may be recommended (or even critical for) individual risk
stratification, especially due to the data collected from expired gas
measurement and analysis. This could be relevant in master athletes, in
individuals with cardiovascular and/or pulmonary diseases who are involved
in recreational competition (e.g. half-marathons, marathons, mountain
climbing, cycling, water sports, etc.), as well as in professional athletes.
In these circumstances and whenever possible, it is best to use an exercise
stress testing that closely approximates the patient's sport.
Among the additional clinical information that CPET can reveal about athletes
or active, healthy individuals, two types stand out: (a) more precise and
objective identification of limiting factor(s) for maximum effort
(cardiovascular, respiratory and muscular or metabolic) and (b) evaluation
of systolic volume behavior, which is obtained by analysis of the curves and
maximal values of oxygen pulse (VO2/HR) and ventilatory
equivalents (VE/VO2 and VE/VCO2).
62
CPET is already included
in cardiological evaluation of HF patients,
63
in identifying the etiology of effort
dyspnea
64
, and has
more recently been considered capable of identifying myocardial
ischemia
65
,
66
or abnormal responses after cardiac
surgery.
67
In
patients with chest pain, changes in the oxygen pulse during CPET make its
diagnostic and predictive accuracy greater than an exercise stress testing
for detecting or excluding myocardial ischemia.
68
It is the procedure of choice when a valid
and precise measurement of an athlete's aerobic condition is required and HR
thresholds must be determined for exercise prescription.
Recommendation
Recommendation grade
Evidence level
Amateur athletes
IIa
C
Professional athletes
I
B
For more precise stratification of
exercise-limiting factors
IIa
A
CPET should be used when there is a change in resting ECG that may interfere
in its interpretation or when there are suspicious hemodynamic
responses.
Recommendation grade: IIa.
Evidence level: B.
The routine use of CPET to stratify risk of sudden death in apparently
healthy children and adolescents does not seem especially useful.
Recommendation grade: III.
Evidence level: B.
2.3.5. Echocardiogram
An echocardiogram may play a relevant role in PPS since it can diagnose the
main diseases involved in SD in athletes (Table 5). It can also help distinguish between
physiological
alterations in the athlete's heart and HCM painlessly, quickly and at a
relatively low cost. However, it should be reserved for cases where there is
a clinical/family history of heart disease or when a physical examination
gives suspicious results, as well as when changes in resting ECG indicate
cardiomyopathy.
69
Furthermore, in known cases of congenital heart disease, especially those of
low complexity, when physical activity and even high-performance sports are
not contraindicated, a periodic ECG helps evaluate the evolution of the
condition in question and its correct management. Doppler echocardiogram
associated with physical effort is important when verifying cardiac function
during exercise, and it can aid in diagnosis and determining the course of
treatment, especially for HCM patients.
28
Table 5
Main causes of sudden death in athletes
Age < 35
Age > 35
Hypertrophic cardiomyopathy
Coronary artery disease
Arrhythmogenic right ventricular dysplasia
Anomalous origin of coronary arteries
Myocarditis
Valve disease
Pre-excitation syndrome
Conduction system disease
2.3.6. Recommendations
The European Society of Cardiology, in light of the findings of Corrado et
al.
6
(the
previously mentioned 25-year Italian follow up of athletes), has established
a screening program for individuals between 12 and 35 years of age that
includes an initial examination consisting of family history, a physical
examination, and 12-lead ECG. Additional tests will only be performed after
positive findings in initial evaluation.
70
Using ECG in programs for young asymptomatic
athletes (12 to 35 years of age) has proven to be a high-cost strategy, and
no population studies with adequate follow-up have proven its efficacy.
Although this test is considered the most practical method for detecting
cardiac structural changes, its use as a screening tool is generally
reserved for elite athletes, especially in clubs or teams with the necessary
financial resources. ECG may indicate the presence of congenital
abnormalities in athletes, even when the results are normal. However, since
most of these changes are not implicated in the genesis of SD, its use has
not been routinely recommended, especially given that its diagnostic power
in asymptomatic athletes with normal physical examination results is very
low.
71
When CAD is suspected in the initial evaluation, further investigation should
be carried out with more accurate examinations: ECG with physical or
pharmacological stress, myocardial scintigraphy with physical or
pharmacological stress or dynamic cardiac MRI. Studies have suggested
introducing a limited echocardiogram that is restricted to the
two-dimensional mode, which can be performed in 5 minutes. The results
showed good sensitivity and specificity for diagnosing various SD-related
conditions in athletes, especially HCM,
72
which is implicated in more than 30% of SD cases in
young athletes. At the present time, ECG is considered a confirmatory
diagnostic modality to be performed after suspicious results are found in
PPS.
Recommendation grade: I.
Evidence level: A.
There is no evidence to support the use of routine ECG in population
screening programs for asymptomatic individuals.
Recommendation grade: III.
2.3.7. Other Complementary Tests
The use of other diagnostic tools, whether laboratory, graphic, imaging,
invasive or non-invasive, should comply with clinical criteria and
scientific evidence already established in the literature, depending on the
PPS findings.
2.3.8. Final Recommendations
The recommendations in Table 6 can be
used as a population screening research strategy. Associations and governing
councils of professional athletes currently have their own protocols, given
the legal and economic issues involved. PPS based on initial clinical
consultation and 12-lead ECG can help identify athletes at greater risk of
SD.
Table 6
Recommendations by age group and competitive level
Leisure
Amateurs
Professionals
Children/adolescents
Initial evaluation + 12-lead ECG
Initial evaluation + 12-lead ECG
Initial evaluation + 12-lead ECG
18-35 years
Initial evaluation + 12-lead ECG
Initial evaluation + 12-lead ECG
Initial evaluation + 12-lead ECG
35-59 years
Initial evaluation + CAD risk evaluation +
12-lead ECG + (consider functional test)
Initial evaluation + CAD risk evaluation +
12-lead ECG + (consider functional test)
Initial evaluation + CAD risk evaluation +
12-lead ECG + (consider functional test)
> 60 years
Initial evaluation + 12-lead ECG + functional
test
Initial evaluation + 12-lead ECG + functional
test
Initial evaluation + 12-lead ECG + functional
test
12-lead ECG: resting 12-lead electrocardiogram; CAD: coronary
artery disease.
3. Genetic Evaluation and Exercise
According to consensus and expert opinion, genetic assessment is not routinely
recommended for athletes. If the question of whether a 12-lead resting ECG should
be
included in routine PPS is still being discussed, it follows that there must be a
pressing reason for genetic investigation of an athlete.
There are two occasions when genetic evaluation is especially well indicated
when:
74
there is a family history of hereditary heart disease (cardiomyopathy,
channelopathies, aortic diseases) or suspicion thereof (episodes of syncope,
arrhythmias, cardiac arrest/SD). In such cases, it is important to point out
that genetic study must first be performed on the individual or an effected
family member. When a causal mutation has been detected, then the other
family members should be studied (including the athlete if not initially
tested);
the athlete has a phenotype that strongly indicates an inherited disease
(signs, symptoms and/or test results suggestive or compatible with a
specific disease).
75
,
76
Clinical genetic assessment should always be the first step before genetic testing
is
conducted. This assessment should include a thorough anamnesis of family history as
well as a complete physical examination. Family history should include aspects such
as the age of symptom onset, the activities that triggered the symptoms, diagnosed
diseases, and the number of affected relatives and degree of kinship. Thus, a
thorough understanding the family tree or "family pedigree" will guide the
investigation toward the affected side of the family. When there are no suspect
first-degree relatives, the study should be extended to another generation if there
is a great suspicion of inherited heart disease.
More recent studies have highlighted the role of genetic study in the "molecular
autopsy" of individuals without anatomical changes who died suddenly.
77
-
79
A comprehensive analysis of genes
related to SD in subjects who died suddenly during exercise has identified potential
causative variants. However, the effects of many genetic variants are still
undetermined and further study is needed to understand their clinical significance.
However, comprehensive genetic analysis of individuals who died during exercise
could determine potential causative variants and help identify relatives at
risk.
77
Specific
recommendations about genetic analysis are addressed in the sections on inherited
diseases in this Guideline.
3.1. Positive Genotype and Negative Phenotype
Individuals can be considered to have positive genotype/negative phenotype
when:
They have a potentially pathogenic mutation.
Complementary exams indicate no clinical manifestations or
structural/electrical changes in the heart.
The question is whether these subjects are at increased risk of SD, even without
the signs of structural heart disease. This is of paramount importance because
in certain cases the adrenergic stress of intense or competitive exercise can
trigger complications and SD. Reviewing the family history of inherited heart
disease can be a great challenge, which is mainly due to variable expressivity
(i.e., severity frequently varies, even within the same family), as well as to
reduced penetrance (i.e., some patients may never develop the
disease).
80
Many
investigated diseases are autosomal dominant, although some are due to
de novo mutations. The age of onset may also vary, with
patients remaining asymptomatic over a long period of the disease, which makes
initial clinical diagnosis difficult.
76
When faced with this diagnostic challenge, we must determine that the phenotype
is truly negative. A thorough cardiologic investigation with ECG,
echocardiogram, cardiac magnetic resonance, Holter monitoring, and provocative
tests (exercise or drugs) should be performed when genetic disease is
suspected.
81
The
current European PPS recommendations state that after a detailed questionnaire
(including symptoms and family history) and clinical examination, priority
should be given to 12-lead ECG. Athletes with two or more "borderline ECG
findings" or any "abnormal ECG findings" require further
investigation.
76
The European Society of Cardiology reported that SD occurs three times more in
athletes (2.3 per 100,000 individuals) than non-athletes (0.9 per 100,000
individuals).
76
There
have been a limited number of SD cases in asymptomatic HCM patients. Five cases
of premature SD have been reported in which the autopsy revealed no macroscopic
HCM or mutation of the TNNT2 gene.
82
Two patients were found with ventricular fibrillation and
normal hearts who subsequently developed HCM and MYH7 gene mutation.
83
In one ARVD case, a
13-year-old mutation carrier in the non-clinically affected DSP (desmo- toquine)
gene suffered SD two years after the genetic study.
84
In an Italian study of 12,500 athletes, only
one case of SD due to ARVD was not clinically detected.
85
In the context of dilated
cardiomyopathies, a case of SD was also described in a 35-year-old female with
LMNA gene (c908-909delCT) mutation in whom no structural disease or conduction
disorder was detected.
86
In assessing positive genotype/negative phenotype in the early development of
cardiomyopathy, it is important to remember that intense sports activity can
worsen the prognosis for mutation carriers, as in ARVD and HCM.
87
,
88
The current recommendations are controversial, being based on expert consensus
and the available few longitudinal studies. Table 7 shows general differences between
U.S. and European
recommendations. For example, the American Heart Association and American
College of Cardiology state that patients with HCM-positive genotypes may
participate in competitive sports, as long as two-dimensional echocardiogram
indicates they are asymptomatic and without evidence of LVH and they have no
family history of HCM-related SD (Class IIa; Evidence level C). However,
athletes with clinically expressed and diagnosed HCM should not participate in
most competitive sports.
89
It
is our opinion that future studies should evaluate the pathogenic potential and
negative effects of intense exercise on individuals with positive genotypes.
Finally, we believe that disqualification should only be used as a final
intervention and that adequate information and decision-making (by the family,
athlete, coach, sponsor, etc.) should be sought.
Table 7
U.S. vs. European recommendations for athletes with positive
genotypes
Heart Disease
American Heart Association/American College of
Cardiology
European Society of Cardiology
Cardiomyopathies (HCM, DCM, ARVD)
No restrictions (e.g., asymptomatic and without
left ventricular hypertrophy)
Competitive sports prohibited: only
non-competitive sports and leisure activities permitted
Long QT
No restrictions (except QTL1 and swimming)
Competitive sports prohibited: only
non-competitive sports and leisure activities permitted
Catecholaminergic tachycardia
Competitive sports prohibited
Competitive sports prohibited
Brugada syndrome
No restrictions
No restrictions
Marfan Syndrome
Mild-to-moderate activity only (no family history
of aortic dissection or SD)
Competitive sports prohibited
HCM: hypertrophic cardiomyopathy; DCM: dilated cardiomyopathy; ARVD:
arrhythmogenic right ventricular dysplasia.
4. Individuals with Cardiomyopathies and Myocarditis
4.1. Hypertrophic Cardiomyopathy
HCM is one of the major causes of sports-related SD in individuals under 35 years
of age.
90
,
91
The U.S. National Registry of Sudden Death in Athletes
evaluated the causes of SD in competitive athletes between 1980 and 2011. Of
2,406 total deaths identified in young athletes (mean age: 19 years), 842 had
some cardiovascular diagnosis. HCM was the most common cause of SD, occurring in
36% of the cases.
92
However,
its contribution to SD in athletes has been systematically overestimated. Recent
evidence from a meta-analysis
92
indicates that HCM caused 10.3% of athlete deaths, while
27.5% had structurally normal hearts.
HCM is an autosomal dominant genetic disease characterized by myofibrillar
disarray in myocytes, accompanied by hypercontractility and asymmetrical
hypertrophy (with or without obstruction of the outflow tract), which are
unexplained by pressure, volume overload, or another underlying systemic
condition. Ventricular hypertrophy (determined by an imaging method) > 15 mm
in any segment with no other apparent cause is highly suggestive of
HCM.
93
For hypertrophy
between 13 and 14 mm, other factors, such as family history, specific ECG
changes, symptoms, another imaging method and even genetic evaluation should be
considered in the differential diagnosis.
94
In first-degree relatives of a HCM patient, hypertrophy
greater than 13 mm is also highly indicative of this disease.
91
Hypertrophy related to
pressure overload, physical training and basal septal hypertrophy in the elderly
should be considered in the differential diagnosis.
HCM patients may be totally asymptomatic or present symptoms such as lipothymia,
syncope, dyspnea, palpitations or angina, especially when related to increased
myocardial demand or obstruction of the outflow tract, as occurs during
exercise. SD in these patients occurs primarily due to ventricular arrhythmias,
although other complications such as supraventricular arrhythmias (with or
without pre-excitation), advanced atrioventricular block, asystole, and
myocardial infarction may also be the cause of this undesired event.
4.1.1. Genetics and Hypertrophic Cardiomyopathy
At present, at least 20 genes have been implicated in the genesis of this
disease,
95
and
more than 1,700 mutations related to contractile myocardial protein have
been discovered. Mutations in at least 11 different genes that code for
sarcomeric proteins have been identified in up to 70% of family
cases.
96
,
97
Mutations of genes in the beta-myosin heavy chain
(MYH7) and myosin-binding protein C (MYBPC3) are the most frequent.
Together, MYBPC3 and MYH7 account for up to half of all clinically
recognized cases of HCM, and make up at least 75% of the index cases in
which a mutation is identified.
98
Other less frequent mutations are related to the
troponin I and troponin T genes (TNNI3, TNNT2) and alpha-tropomyosin-1
(TPM1), whose frequency is often less than 5%. Still less common (less than
1%) are mutations of muscle LIM protein (CSRP3), troponin C (TNNC1) and
titin (TTN). Genetic phenotypes such as Fabry disease, amyloidosis, Danon
disease and Friedreich ataxia should also be considered.
95
Mutations in troponin
genes, although less common (15% to 30%), have been most closely associated
with SD,
99
including, in
some reports, individuals with no phenotypic manifestations of the
disease.
Genetic counseling by a multidisciplinary team experienced in genetically
determined heart disease is recommended for individuals with HCM.
Recommendation grade: I.
Evidence level: C.
Genetic sequencing study for patients with clinically diagnosed HCM (index
cases).
Recommendation grade: I.
Evidence level: B.
Assessment for specific mutations in direct relatives of patients diagnosed
with genetically determined HCM.
Recommendation grade: I.
Evidence level: B.
4.1.2. Complementary Exams in Hypertrophic Cardiomyopathy
4.1.2.1. Electrocardiogram
ECG should be performed in all patients with suspected HCM.
Recommendation grade: I.
Evidence level: B.
About 90% of patients with HCM have ECG changes, with ST-segment and
T-wave being the most common. Athletes with HCM have a higher prevalence
of T-wave changes (especially deep T-wave inversion in the lateral
leads) and ST-segment changes than non-athletes with the disease. In
addition to these changes, there is left atrial enlargement, which is
identified by a prolonged P-wave duration (> 120 ms) in leads I or II
with a negative P-wave portion ≥ 1 mm in depth and ≥ 40 ms
in duration in the V1 lead. Complete left bundle branch block may also
be suggestive of HCM. In the past, some ECG changes in athletes were
considered potentially pathological, such as: left atrial enlargement
and left axis deviation, T-wave inversion confined to V1-V4 preceded by
J-point elevation (especially in blacks), Q-waves ≥ 3 to 4 mm
(with an amplitude less than one-quarter of the R-wave and a duration
< 0.04 s). However, such changes are now considered physiological
responses in the athlete's heart, and do not require additional clinical
evaluation.
100
,
101
4.1.2.2. Echocardiogram
This exam play a fundamental role in HCM assessment. In addition to the
degree of hypertrophy, they can determine the gradient between the left
ventricle (LV) and the aorta, as well as the presence of mitral valve
abnormalities: systolic anterior motion and altered patterns of
diastolic function.
93
,
102
Echocardiograms also have an important role in
differentiating between hypertrophy due to HCM and that due to physical
training (ventricular hypertrophy in the athlete's heart). A variety
information, such as the pattern and distribution of hypertrophy,
parietal thickening, cavity size, assessment of diastolic function by
tissue Doppler imaging, and family history are required.
103
When not clinically
differentiated, ECG, echocardiograph, functional or other imaging
methods, such as serial ECG, may be useful when evaluating athletes with
suspected HCM before and after a detraining period (Table 8).
104
Regarding prognosis, LV wall
thickness > 30 mm is a major risk factor for SD, especially in
adolescents and young adults.
105
A gradient above 50 mmHg between the LV and
the aorta is also associated with worse prognosis.
106
Table 8
Factors indicative of athlete's heart syndrome (vs. HCM) in
athletes with left ventricular hypertrophy in the "gray zone"
(i.e., wall thickness: 13-15 mm)
Clinical
No family history
Absence of diffuse T-wave inversion in
ECG
Nuclear magnetic resonance
Homogeneous distribution of left
ventricular hypertrophy
No late gadolinium enhancement
(fibrosis)
Echocardiogram
Increased left ventricular diameter (LVDD
> 55 mm)
Symmetrical hypertrophy (septum, posterior
wall, apex and base)
Normal diastolic function (E/A ratio >
1, peak velocity to E' > 11.5 cm/s)
Hypertrophy regression after
detraining
No HCM-causing mutations found in genetic
analysis
LVDD: left ventricular diastolic diameter; ECG:
electrocardiogram; HCM: hypertrophic cardiomyopathy.
When comparing athletes and non-athletes with HCM from an
echocardiographic point of view, athletes present the following
characteristics: lower LV wall thickness, higher left ventricular
end-final diastolic diameter and higher ejection fraction.
4.1.2.2.1. Transthoracic Doppler Echocardiogram
Confirm clinical suspicions of HCM by determining parietal thickening
and whether there is a dynamic gradient.
Recommendation grade: I.
Evidence level: B.
Investigate the presence of HCM in first-degree relatives.
Reassessment of clinical evolution, as well as therapeutic
interventions.
Recommendation grade: IIa.
Evidence level: C.
Annual reassessment of family members of HCM patients aged 12 to 18
years.
In individuals over 21 years of age, reevaluation should be done
every 5 years.
Tissue Doppler imaging should be performed to differentiate HCM from
physiological or pathological cardiac hypertrophy (e.g.
hypertension).
An exercise echo stress test should be used in asymptomatic patients
who do not show significant gradients at rest or with the Valsalva
maneuver.
Recommendation grade: IIa.
Evidence level: C.
4.1.2.2.2. Transesophageal Doppler Echocardiogram
Patients with an inadequate transthoracic window.
Transesophageal Doppler echocardiogram is used to assess valve damage
and the mechanism and magnitude of mitral regurgitation when this is
unclear after transthoracic ECG.
Intraoperative evaluation for myomectomy and alcohol septal
ablation.
Recommendation grade: I.
Evidence level: B.
To clarify the mechanism of atypical mitral regurgitation.
Recommendation grade: IIa.
Evidence level: B.
4.1.2.3. Cardiac Magnetic Resonance Imaging
Cardiac magnetic resonance imaging (CMRI) is used to evaluate patients
with suspected HCM when an ECG is inconclusive. Although ECG is the
first imaging choice for patients with suspected HCM, this method may be
limited by poor acoustic windows, particularly for areas such as the
cardiac apex.
107
CMRI
can also be used in highly suspicious cases that are not confirmed by
ECG. Its excellent spatial resolution provides exclusive information
about cardiac muscle and tissue, helping in the differential diagnosis
of secondary causes of hypertrophy, such as amyloidosis and sarcoidosis.
This examination allows the visualization of subtle changes in the
thickness and contractility of the LV over time, as well as the
detection of fibrotic areas, and recent studies have reported the
presence and amount of fibrosis with prognosis.
107
,
108
CMRI is used to evaluate athletes with ECG abnormalities that are
suspicious of HCM and inconclusive ECG findings.
Recommendation grade: I.
Evidence level: B.
CMRI should be used for myocardial fibrosis screening in every athlete
with suspected HCM.
Recommendation grade: IIa.
Evidence level: B.
4.1.2.4. Exercise Tests and Hypertrophic Cardiomyopathy
The exercise stress testing is an independent means of identifying
patients at increased risk of SD. Since the presence of marked
ST-segment changes in HCM patients may indicate ischemia but not
necessarily heart disease, the exercise stress testing has little
diagnostic value. However, it could be a prognostic marker to be taken
into consideration, especially when associated with expired gas
measurements (CPET).
109
,
110
For these patients, a ramp protocol should be used first. This test
avoids sudden changes in the recruitment of neuromuscular motor units
and the metabolic changes associated with incremental protocols due to
the constant and continuous increase of external work. The slope of the
ramp should be individualized to last, preferably, from 8 to 12
minutes.
109
4.1.2.4.1. Exercise Testing Recommendations for Patients with
Hypertrophic Cardiomyopathy
The exercise stress testing is recommended for asymptomatic HCM
patients who do not present high risk criteria as an associated
element in prognostic stratification.
Exercise stress testing is recommended for asymptomatic patients
without high risk criteria, but who wish to participate in
recreational physical activity.
It is an additional element in differential diagnosis between
athlete's heart syndrome and HCM.
Recommendation grade: I.
Evidence level: B.
The exercise stress testing can be used for patients with doubtful
symptoms that are not associated with other high-risk criteria
(preferably CPET).
It can be used to assess functional capacity and heart rate response
to exercise in patients with an implanted defibrillator who wish to
participate in low-intensity physical activity.
Recommendation grade: IIa.
Evidence level: C.
In athletes with high risk criteria (symptomatic), it can facilitate
differential diagnosis between HCM and physiological
hypertrophy.
Recommendation grade: III.
4.1.2.4.2. The Role of Maximal Cardiopulmonary Exercise Testing
in Hypertrophic Cardiomyopathy
A maximal CPET can stratify HCM patients regarding cardiovascular
morbidity and mortality, helping guide treatment. In athletes who
are in the "gray zone" between physiological hypertrophy and the
pathological hypertrophy of HCM, measuring oxygen consumption and
peak oxygen pulse with a CPET can be of great assistance. In
general, highly trained athletes have values between 55 and 70
mL.kg-1.min-1. Sharma et al.
111
demonstrated
that healthy athletes can actually achieve significantly higher peak
oxygen consumption than athletes with HCM (66.2
mL.kg-1.min-1 vs. 34.3
mL.kg-1.min-1). Since there was no overlap
between groups, the researchers postulated a cutoff of 50
mL.kg-1.min-1 to discriminate between the
pathological hypertrophy of HCM from the dynamic component of the
athlete's heart.
Finally, since there are conflicting data regarding CPET and specific
predictions of SD in patients with HCM based on VE/VCO2
slope, neither VE/VCO2 slope nor peak VO2 are
currently used in risk stratification.
112
Recommendation grade: IIa.
Evidence level: B.
4.1.3. Sports and Hypertrophic Cardiomyopathy
Why is there a low prevalence of HCM among high-level athletes? The response
seems to be related to a natural selection process that excludes individuals
with HCM-related functional and structural alterations from the
high-intensity training required to become a professional. So, is being a
competitive athlete with HCM synonymous with SD? The answer is no. We all
know cases of athletes who were diagnosed with this disease well into their
professional careers or after they had already retired. The problem is that
intense exercise can trigger severe arrhythmias, increased left ventricular
outflow obstruction and/or ischemic compression in small blood vessels
(possible fibrosis due to repetitive ischemia) during training and
competition.
Based on the premise that strenuous exercise can be an important trigger for
SD, athletes with a probable or unequivocal diagnosis of HCM should be
excluded from most competitive sports. However, it should be pointed out
that only a minority of HCM patients have SD or cardiac arrest during
exercise.
113
This
recommendation is independent of age, sex, phenotype, symptoms, LV outflow
tract obstruction, drug treatment, septal ablation, or pacemaker or
implanted defibrillator.
89
Although criteria have been suggested
114
,
115
for establishing SD risk factors in HCM patients
(Table 9), it should be pointed
out that such criteria should be used with caution, since they do not take
important HCM-related aspects into account, such as genetics and CMRI
results.
Table 9
Risk factors for sudden death in HCM patients
Greater risk factors
Cardiorespiratory arrest survivor
Spontaneous sustained ventricular
tachycardia
Family history of SD in patients < 40
years
Unexplained syncope or pre-syncope
Interventricular septum > 30 mm
Minor risk factors
Abnormal blood pressure response to
exercise
Patients under 30 years of age
Nonsustained ventricular tachycardia
HCM: hypertrophic cardiomyopathy; SD: sudden death
Individuals classified as low risk (especially those without a gradient at
rest or during effort)
116
may participate in sports such as golf, billiards, bowling and shooting
(group IA). Recreational sports that require high intensity or abrupt
changes of intensity are not recommended. Individuals with positive
genotype/negative phenotype (without clinical evidence of disease) may
participate in sports, provided they are assessed periodically, since the
chance of SD is directly related to the presence of hypertrophy and
fibrosis. A recent study evaluated vigorous exercise in HCM patients and
individuals with positive genotype/negative phenotype. Exercise was
associated with higher cardiac volumes and better diastolic function, but
not with a higher incidence of ventricular arrhythmias.
117
Participation in competitive sports for clinically diagnosed HCM
patients.
Recommendation grade: III.
Evidence level: B.
4.2. Arrhythmogenic Right Ventricular Dysplasia
ARVD is a cardiac muscle disease of genetic origin characterized by changes
during the formation of desmosomes. It is clinically manifested by the
replacement of myocardial tissue with fatty and/or fibrous tissue, generally
affecting the right ventricle and with more pronounced clinical manifestations
when the apical septum of the LV is affected. Mutations in non-desmosomal genes
have also been identified, such as filamin C, TMEM43 and phospholambam,
especially in cases involving the LV.
118
,
119
Among athletes from the Veneto region of Italy, ARVD
is a major cause of SD: one study found a five-fold increase in SD risk for
young athletes who participated in competitive sports.
120
Based on recent data, ARVD is ranked as the
third most frequent cause of SD the United Kingdom.
88
ARVD is a rare condition in the general
population, with an estimated prevalence of 1 in 5,000, although in some
European countries, such as Italy and Germany, the prevalence is 1 in
2,000.
121
Diagnosis
can be challenging given the need to exclude other disorders that may present
with similar signs and symptoms.
122
The main clinical manifestations are palpitations,
syncope, chest pain, complex ventricular arrhythmias and SD. Since highly
trained athletes may have right ventricular (RV) hypertrophy, in addition to a
variety of changes in depolarization, repolarization, and nerve conduction, a
differential diagnosis between "athlete's heart syndrome" and ARVD should always
be performed. Since an echocardiogram may have technical limitations with
respect to RV images, its structural and functional analysis may be impaired.
However, akinesia, dyskinesia or RV aneurysms associated with the dilation of
this chamber are among the most important criteria in the revised
classification. CMRI is a noninvasive imaging technique that has become the main
tool for diagnosing ARVD. Segmental or global dysfunction of the RV or a
substantial increase in this cardiac chamber, associated with myocardial
thinning and presence of late enhancement (fibrosis and/or edema), supports a
diagnosis of ARVD.
121
,
123
A 12-lead resting ECG and Holter monitoring can help
with diagnosis, principally by detecting arrhythmias such as branch block
pattern ventricular tachycardia, inverted T-waves in the right precordial leads
(V1 to V3) and epsilon waves (present in 30% of ARVD patients). Family history
should always be investigated, and a confirmed case in a first degree relative
is a major criterion. Thus, suspected first-degree cases or confirmed
second-degree cases are minor criteria. In especially difficult cases, a biopsy
of the RV can be performed. The final clinical diagnosis may not be simple. The
presence of two major criteria, one major and two minor criteria (different
categories) or four minor criteria (different categories) confirm the
diagnosis.
New evidence suggests that ECG adaptations, such as isolated right ventricular
overload or T-wave inversion from V2 to V4 (associated with right axis right
deviation in black athletes) are related to benign structural adaptations of the
heart in competitive athletes. In these individuals careful investigation for
the other criteria is necessary, and research on family history is of
fundamental importance.
124
4.2.1. Diagnosis and Management of Athletes with Suspected Arrhythmogenic
Right Ventricular Dysplasia
4.2.1.1. Echocardiography
In athletes with a family history of ARVD or with ECG changes suggestive
of ARVD.
Recommendation grade: I.
Evidence level: C.
4.2.1.2. Cardiac Magnetic Resonance Imaging
CRMI should be used when there is a strong suspicion, despite a
non-diagnostic ECG or in cases where an echocardiogram could not
adequately assess the RV.
Recommendation grade: I.
Evidence level: C.
Competitive physical activity in patients with a definite or probable
diagnosis of ARVD.
Recommendation grade: III.
Evidence level: B.
There is sufficient evidence that exercise can trigger SD in individuals
with ARVD. Probable causes include: increased sympathetic tone and even
greater dilation of the ventricular chambers during exercise, which,
associated with myocardial fibrosis, leads to the appearance of complex
arrhythmias.
125
,
126
Adhesion between the cells could be
compromised by genetic factors, and in the meantime, mechanical stress
from exercise can lead to cardiomyocyte apoptosis and worsening of the
disease.
127
,
128
Group 1A sports can be allowed on an
individual basis. More recent studies have confirmed the deleterious
role of sustained vigorous physical activity (> 6 metabolic
equivalents) in the occurrence of ventricular arrhythmias in ARVD
patients, and reducing exercise after diagnosis is associated with a
lower occurrence of severe arrhythmias.
129
,
130
4.3. Myocarditis
Myocarditis has a heterogeneous clinical profile and, although not very
prevalent, it is the probable cause of 5 to 22% of SD cases in athletes,
depending on age and region.
88
,
131
This disease is characterized by an inflammatory process
with consequent non-ischemic degeneration and necrosis of the myocardium.
Generally, myocarditis is the result of an infection (viruses, bacteria, fungi,
protozoa), but it may be associated with substance use or autoimmune
diseases.
132
SD may
occur in the acute phase (when a myocarditis patient does not abstain from
sports for 6 months), or even in the chronic phase, when there is already scar
tissue in the myocardium, which is a consequence of complex arrhythmias
triggered by an unstable electrical substrate. In this phase, exercise may be
the arrhythmogenic trigger due to increased venous return and muscle fiber
stretching from physical activity.
133
,
134
In athletes, the main symptoms are palpitations, precordialgia, dyspnea, fatigue
and syncope. ECG changes include ventricular arrhythmias, ST-T segment changes,
and rhythm and conduction disorders. It may evolve with left ventricular
enlargement due to the disease, hypertrophy due to physical training or a
combination of both.
135
,
136
CMRI and myocardial biopsy (although less common in
our country) may facilitate diagnosis. Due to their prevalence in Brazil, we
point out that myocarditis may also be caused by the dengue and HIV viruses, as
well as by Chagas' disease.
4.3.1. Recommendations for Athletes with Myocarditis
Competitive physical activity for patients with active myocarditis.
Recommendation grade: III.
Evidence level: B.
Athletes diagnosed with myocarditis should be advised against practicing any
competitive sports and should undergo a period of convalescence. Although
there is no consensus, many experts recommend that this period be at least
six months after the onset of clinical manifestations. However, some experts
have been more "liberal", recommending shorter periods of convalescence.
These athletes may resume training and competition after:
Left ventricular function, ventricular wall motion, and cardiac
dimensions return to normal values (based on stress and resting
echocardiography and radionuclide imaging).
Complex or frequent forms of ventricular and supraventricular
arrhythmias and clinically relevant arrhythmias are absent.
Inflammatory and heart failure markers are normalized.
Resting ECG is normalized, although the persistence of ST-segment
changes alone should not impede the athlete's return to training
and competition.
4.4. Dilated Cardiomyopathy
Dilated cardiomyopathy (DCM) has an estimated prevalence of 40 cases per 100,000
individuals. It is defined as a myocardial disease, characterized by LV dilation
and global systolic dysfunction, and there may be overlapping segmental
abnormalities with increased myocardial mass. DCM includes disorders of genetic
origin, disorders due to infection, inflammation, exposure to toxic substances
or metabolic diseases, and disorders of idiopathic origin (although at least 40%
of disorders classified as idiopathic are, in fact, of genetic origin). Up to 40
genes have been identified, with proteins from several cellular structures being
affected (sarcomere, sarcolemma and intercellular junction).
137
DCM patients vary widely in
clinical presentation and hemodynamics.
138
Long-term aerobic training may lead to changes in cardiac morphology, including
increased LV cavity size and mass. Increased cavity size may produce a greater
systolic volume and thus, the resting ejection fraction may be at the lower
limit of normal or slightly reduced. In this context, it is important to
differentiate between LV increase due to systematic training and that due to
DCM.
138
4.4.1. Complementary Examinations for Dilated Cardiomyopathy
4.4.1.1. Exercise Stress Testing and Cardiopulmonary Exercise
Testing
Although exercise performance may only be slightly reduced in young DCM
patients, arrhythmias are usually present at a very early stage of the
disease (including supraventricular and ventricular tachyarrhythmia, as
well as conduction delays).
Recommendations for exercise stress testing
and CPET
38
Recommendation grade
Evidence level
Exercise stress testing or CPET to assess
individuals with known or suspected ventricular
arrhythmias during exercise, regardless of age
I
C
Exercise stress testing to assess DCM
severity
IIb
B
CPET to assess DCM severity
Ia
B
Exercise stress testing to identify
pathophysiological mechanisms and clarify symptoms
IIb
B
CPET to identify pathophysiological
mechanisms and clarify symptoms
I
B
CPET: cardiopulmonary exercise testing.
4.4.1.2. Echocardiogram
An echocardiogram is more sensitive than ECG for diagnosing LVH and
accurately quantifies LV mass. Thus, cardiac abnormalities detected by
an echocardiogram have additional predictive value.
138
,
139
Recommendations for performing
ECHO
Recommendation grade
Evidence level
Assessment of patients with suspected
DCM or heart failure
I
B
Assessment for differential diagnosis
between DCM and "athlete's heart syndrome"
I
B
Echo: echocardiogram.
4.4.1.3. Cardiac Magnetic Resonance Imaging
CMRI can clearly and effectively demonstrate and quantify anatomical and
functional changes in DCM. This examination has been found useful for
evaluating HF patients by accurately calculating the function of both
ventricles. It also helps distinguish idiopathic DCM from other forms of
ventricular dysfunction, such as ventricular dysfunction caused by
coronary artery disease.
140
In addition, the method makes an important
contribution to prognostic evaluation. Determining the presence and
extent of fibrosis by myocardial late enhancement has good prognostic
value, since it represents a substrate for arrhythmia and SD. Further
research is needed to confirm the role of CMRI in the prognostic
stratification of DCM, especially when defining the arrhythmic risk of
these patients.
141
4.4.2. Sports and Dilated Cardiomyopathy
DCM is an uncommon myocardial disease that deserves consideration because it
is a potential cause of SD in athletes.
142
-
144
In reality, there is little information on the
risk of SD during physical activity or the relative risk of physical
training for athletes with DCM. Thus, it is not clear whether asymptomatic
DCM patients are at risk of SD during physical activity or competitive
sports, since tachyarrhythmias are much more common in patients with more
advanced disease, i.e., with explicit cardiac symptoms and reduced ejection
fraction.
4.4.2.1. Recommendations for Athletes Diagnosed with Dilated
Cardiomyopathy
Until further information is available, symptomatic DCM athletes should
not participate in competitive sports except for those in class IA and
selected cases.
Recommendation grade: III.
Evidence level: B.
Athletes with a definite DCM diagnosis but a low risk profile
(asymptomatic, no family history of SD, slightly reduced ejection
fraction, normal pressure response to exercise and no complex
ventricular arrhythmias) could participate in low-to-moderate intensity
dynamic exercise and low-intensity static exercise (recommendations IA
and IB).
These recommendations apply to competitive exercise. Physical activity of
a therapeutic nature (cardiac rehabilitation) is indicated for all DCM
and heart failure patients.
145
4.5. Non-Compacted Cardiomyopathy
Non-compacted cardiomyopathy is a rare cardiac disease that has been recently
recognized. It is due to embryonic interruption of myocardial compaction and is
characterized by segmental thickening of the LV walls that consists of two
layers: a compacted epicardial layer and an endocardial layer with marked
trabeculations and deep intratrabecular recesses that are filled by blood flow.
In non-compacted cardiomyopathy, left ventricular capacity is usually increased
and the ejection fraction is reduced.
146
,
147
Although considered a rare condition by some researchers, the incidence and
prevalence of non-compacted cardiomyopathy are uncertain. Using
echocardiography, a study at a large institution found a prevalence of 0.05%.
Among HF patients, the prevalence of non-compacted cardiomyopathy is
4%.
148
Diagnosis is
quite difficult due to the lack of clear criteria, as well as the condition's
heterogeneous clinical spectrum and the usual need for MRI for a reliable
diagnosis.
This disease may be asymptomatic or present with HF, ventricular and/or atrial
arrhythmias, pre-excitation, thromboembolic events or SD. However, the risk of
adverse consequences, including SD, seems to be associated with the degree of LV
systolic dysfunction and/or ventricular tachycardia.
149
There are no universally accepted criteria
or precise guidelines for morphological diagnosis. However, a
non-compacted/compacted myocardium ratio of > 2.1:1 at the end of systole in
an echocardiogram or of 2.3:1 at the end of systole in CMRI is currently the
most widely accepted criterion.
150
Non-compacted cardiomyopathy can be found alone or combined with congenital heart
defects, neuromuscular disorders or as part of genetic syndromes.
149
It is a genetically
heterogeneous disease, with familial or sporadic cases, and with pathogenic
mutations involving the cytoskeleton, mitochondria, sarcomeres and z-line
proteins. Therefore, different forms have been described: autosomal dominant,
autosomal recessive, X-linked, and with mitochondrial patterns of inheritance,
although the most common form has an autosomal dominant trait.
146
4.5.1. Sports and Non-Compacted Cardiomyopathy
Neither the extent to which physical training can alter non-compacted
cardiomyopathy nor the prevalence of non-compacted LV morphology among
healthy athletes have been determined.
151
,
152
Since forensic reports of SD in young athletes do
not include non-compacted cardiomyopathy as a possible cause, it is not
possible to apply risk stratification strategies for new patients with this
disease.
Recent studies have found a higher prevalence of increased LV trabeculation
among athletes than controls (18.3% vs. 7%). It is believed that these
abnormalities represent a non-specific epiphenomenon that increases with
higher image resolution in echocardiography. In addition, increased LV
trabeculation or isolated echocardiographic criteria for cardiomyopathies
are likely to be of little significance and may be a part of the athlete's
heart.
153
,
154
Thus, not all athletes with isolated ventricular
non-compaction should be diagnosed with non-compacted cardiomyopathy.
Therefore, functional parameters such as ejection fraction must be
considered in patient management.
154
4.5.1.1. Recommendations for Athletes Diagnosed with Non-Compacted
Cardiomyopathy
Athletes with an unequivocal diagnosis of non-compacted cardiomyopathy
and compromised systolic function, major ventricular tachyarrhythmias in
Holter monitoring or at an exercise testing or a history of syncope
should not participate in competitive sports, with the possible
exception of low-intensity sports (class IA), at least until more
clinical information becomes available.
Recommendation grade: III.
Evidence level: C.
4.6. Chagas Disease
Chagas disease continues to be one of the most important causes of non-ischemic
cardiomyopathy in Latin America. Approximately 8-10 million people are estimated
to be infected with Trypanosoma cruzi,
155
and this protozoa is
responsible for approximately 12,000 deaths per year.
156
The disease usually manifests itself in 30%
to 40% of those infected, and clinical findings usually appear 10 to 30 years
after initial infection.
157
Cardiac arrhythmias and SD are common and may occur at any stage of progression,
even in individuals without significant structural disease.
158
,
159
Sustained ventricular
tachycardia is the main cause of SD, and is associated with LV dysfunction,
syncope and non-sustained ventricular tachycardia in Holter monitoring or the
exercise testing.
160
,
161
In addition, sinus node dysfunction, atrioventricular
and intraventricular conduction disorders are common findings in patients with
Chagas disease and may progress to complete atrioventricular block. Few studies
have evaluated the risk of SD in Chagas patients during intense exercise, and a
lack of symptoms does not exclude the presence of cardiomyopathy, even in
high-level athletes.
162
Diagnosis involves epidemiological and serological evaluation
(immunofluorescence). ECG and echocardiogram facilitate diagnosis of
cardiomyopathy and conduction disorders. An exercise stress testing or a CPET,
MRI, Holter monitoring and even electrophysiological study can more accurately
assess the risk of SD. The exercise recommendations are similar to those for
individuals with DCM.
5. Channelopathies
5.1. Introduction
Channelopathies are inherited arrhythmogenic heart diseases that do not involve
structural impairment and are caused by genetic changes that result in
dysfunction of the cardiac ion channels, which leads to risk of SD.
163
The most commonly known
channelopathies are long QT syndrome, short QT syndrome, Brugada syndrome, and
catecholaminergic polymorphic ventricular tachycardia (CPTV)
75
Sinus node disease and Lenegre
disease or conduction system disease are also examples of channelopathies.
Ion channels, the ion currents moving through these channels, proteins that
attach to the membrane structure of myocardial cells, and the junctions between
these structures are involved in electrical impulse formation and the
synchronous transmission of these impulses throughout the heart, which generates
cardiac action potential.
164
,
165
The performance of each of these functions is
determined by different genes. Mutations in related genes cause specific
dysfunctions and cause channelopathies.
166
,
167
The ion channels in the cell membrane allow ions to
enter and exit following a voltage gradient. Genetic mutation in these channels
can lead to gain or loss of function. With the recent increases in knowledge
about these entities, defibrillator use and easier access to genetic evaluation,
decisions shared between the medical team and the family have allowed a more
permissive stance toward exercise in individuals with channelopathies.
168
Detailed recommendations on
the most prevalent syndromes are described below.
5.2. Long QT Syndrome
Long QT syndrome (LQTS) is the prototype channelopathy. First described more than
50 years ago as an autosomal recessive disease, Jervell and Lange-Nielsen
syndrome
169
,
170
includes congenital deafness, increased QTc intervals,
and syncope or SD. Subsequently, an autosomal dominant form called Roman-Ward
syndrome (prolonged QTc without deafness) was discovered. Several types of LQTS
are currently known, which are determined by gene mutations that cause distinct
changes in ventricular depolarization and repolarization.
The typical clinical features of LQTS include syncope or SD associated with
increased QTc intervals and ventricular tachyarrhythmias such as torsade de
pointes.
171
Typically, certain factors trigger syncope in LQTS, which are related by subtype
and genotype. The most common triggers are: adrenergic activity in SQTL1, sudden
awakening and an acute auditory stimulus in SQTL2 and sleeping/resting in SQTL3.
However, phenotypic presentations vary widely. Carriers can be asymptomatic,
have no increase in QTc interval or have syncope or SD in the first days of
life. Thus, diagnostic criteria were developed to score alterations, which are
divided into three main groups: clinical history, family history and
ECG.
163
5.2.1. Genetic Alterations in Long QT Syndrome
Genetic alterations are known in approximately 60% of the clinical cases of
LQTS, and at least 17 genes have been associated with this clinical entity.
Generally, patients have mutations in three specific genes: KCNQ1, KCNH2 or
SCN5A.
172
Hundreds of mutations have already been described, with the most prevalent
type being cardiac.
173
The most common mutation occurs in the KCNQ1 gene, which is responsible for
more than 30% of the genetic variants and pathological mutations identified
in LQTS and causes SQTL1.
173
This type of mutation causes a loss of function in the
IKs potassium current,
166
which plays an important role in cell repolarization and QT interval
adaptation to heart rate. SQTL5, a mutation caused by the KCNE1 gene, is
much less frequent (considered rare) and is responsible for IKs
loss-of-function.
166
The KCNH2 (HERG) gene, which encodes the alpha subunit
of the fast potassium channels, and KCNE2, which encodes the beta subunit,
are responsible for the rapid entry of potassium during phase 3 of the
action potential.
174
Loss
of alpha subunit function accounts for 40% of genotyped LQTS and is
responsible for SQTL2.
175
SQTL3 accounts for approximately 10% of all mutations diagnosed in LQTS, due
to changes in the SCN5A gene, whose functional gain produces a continuous
sodium input during the plateau phase, which facilitates early
depolarization in cardiac cells. Although hundreds of other mutations have
been described, treatment and follow-up of LQTS patients and families are
restricted to the most known forms.
176
5.2.2. Risk Stratification in Long QT Syndrome
Genetic analysis has been widely used for risk stratification and determining
specific therapeutic interventions in LQTS patients and their relatives.
Since LQTS is an uncommon clinical condition and data have only been
obtained through cohort studies, the evidence level for recommendations
about risk stratification and treatment strategies has been limited to B.
The most robust risk marker of LQTS is a previous episode of aborted SD, and
its most common cause is polymorphic ventricular tachycardia, degenerating
or not into ventricular fibrillation. Patients who have experienced such a
condition have a 13-fold increased risk of new SD episodes. Previous syncope
is also an extremely unfavorable risk marker, which could double the
risk.
177
However, the risk of having an arrhythmic event is not the same for all
patients. Evidence shows that individuals with SQTL2 and SQTL3 have a higher
risk of events than those with the mutations that cause SQTL1. In addition,
individuals with a QTc duration > 500 ms are at higher risk than those
with shorter QTc durations.
172
Mutations involving the gene segment that encodes the
channel pore are also related to poorer prognosis. Therefore, once again,
the value of genotyping in patients with this syndrome is clear. A family
history of SD did not prove to be a higher risk marker for events.
178
5.2.3. Recommendations for Athletes with Long QT Syndrome
A few years ago, LQTS patients were advised not to participate in competitive
sports based on the understanding that they were exposed to an increased
risk of SD. In 2015, Aziz et al.
179
studied more than 100 patients with a positive
LQTS genotype, all engaged in some type of sports program. Of these, 25%
practiced competitive sports. Interestingly, the authors found no
disease-related symptoms during sports, confirming that no event or SD had
been described in those undergoing proper treatment.
179
This and other evidence
led to a revision of the recommendation to universally restrict LQTS
patients from competitive sports. Thus, the American Heart
Association/American College of Cardiology published new eligibility
recommendations for athletes with channelopathies.
180
Participation in competitive sports was
reconsidered for athletes with LQTS due to a lack of evidence that
asymptomatic athletes with positive genotype/negative phenotype may be at
increased risk of malignant arrhythmias during sports. However, athletes
must be under treatment and asymptomatic for 3 months before returning to
training. Furthermore, precautionary measures, such as an automatic external
defibrillator (Table 10), are
advisable. However, it is important to stress that water sports are
contraindicated for athletes with SQTL1.
Table 10
Precautionary measures for patients with channelopathies
Avoid substances that prolong the QT interval
(www.crediblemeds.org)
Avoid substances that exacerbate Brugada
syndrome (www.brugadadrugs.org)
Hydration and replacement of electrolytes:
avoid dehydration (trigger)
Avoid hyperthermia, whether due to fever or
excessive heat in athletes with long QT and Brugada
syndrome
An external automatic defibrillator should be
part of the athlete's equipment
Establish an emergency action plan
Recommendation grade: IIb.
Evidence level: C.
Regarding water sports, Ackerman et al.
180
described the follow up of swimmers diagnosed with
SQTL1 and treated with beta-blockers, many with an implantable
cardioverter-defibrillator (ICD), who chose to continue competing. The
incidence of events was low, with only two events (both in the same
individual) among 74 patients diagnosed with LQTS. It should be noted that
this individual had a history of aborted SD and was not using
beta-blockers.
Beta-blockers are the basis for managing LQTS, and are indicated for all
symptomatic or asymptomatic individuals with a QTc interval ≥ 470 ms.
Therefore, all patients with a prolonged QT interval should receive
beta-blockers, although protection is incomplete for patients with LQTS2 and
3 (class I intervention). For patients with a mutation (positive genotype)
but a normal QT interval, prophylactic use of beta-blockers is also
recommended, given their good tolerability and the fact that at least 10% of
asymptomatic individuals will develop symptoms over time.
181
,
182
Recommendation grade: IIa.
Evidence level: B.
An ICD is recommended for all cardiac arrest survivors with good functional
status and life expectancy > 1 year.
Recommendation grade: I.
Evidence level: B.
Patients who develop syncope despite the use of beta-blockers may also
benefit from ICD.
Recommendation grade: IIa.
Evidence level: B.
An ICD can be considered in patients at high risk of SD, such as those with
SQTL3, even if asymptomatic. Individuals with a QTc interval > 500 ms
present a very high risk.
183
Recommendation grade: IIb.
Evidence level: B.
Sympathetic denervation may be considered for patients with syncope or CPTV
who are already using beta-blockers.
181
,
184
Recommendation grade: IIb.
Evidence level: B.
5.3. Short QT Syndrome
Short QT syndrome is a very rare condition that has been known for less than 20
years.
185
In this
disease, shortening of repolarization occurs, which favors the development of
ventricular arrhythmias by reentry. It is characterized by a short QT interval
(QTc < 320 ms) with peaked T-waves (that could have increased amplitude) with
a normal ascending phase and a rapid descending phase.
186
,
187
A QTc interval ≤ 340 ms is a risk
marker. Short QT syndrome should also be considered when the patient has a QTc
interval ≤ 360 ms in association with a confirmed genetic mutation, a
family history of short QT syndrome, a family history of SD in individuals under
40 years of age and/or in survivors of cardiorespiratory arrest.
188
Since the clinical
parameters are still unclear, genetic analysis is useful to confirm the
diagnosis in suspected cases. Mutations in three genes that encode potassium
channels have been described: KCNH2, KCNQ1 and KCNJ2, all resulting in function
gains in the IKr, IKs and IK1 channels, respectively, and determining short QT
syndrome types 1, 2 and 3.
187
Three other genes that encode calcium channels, CACNA1C (short QT syndrome type
4), CACNB2 (short QT syndrome type 5) and CACNA2D1 (short QT syndrome type 6)
were also identified.
188
Given that the number of patients with a confirmed diagnosis is very small, it
has not yet been determined whether any specific type of mutation determines a
worse prognosis. Moreover, new generation sequencing does not identify any
genetic cause in up to 40% of individuals with a clear phenotype.
188
Risk factors for arrhythmias
are also not known. Treatment for this condition is still controversial: in
patients with a KCNH2 gene mutation, quinidine has been shown to prolong
refractoriness and suppress the induction of arrhythmias during an
electrophysiological study,
189
although for other mutations its usefulness has not been
established. The disease appears to be highly lethal, but there may be a
diagnostic bias toward severe cases. Although the use of ICD may be considered,
inappropriate shocks may occur due to the double-counting phenomenon (QRS
complexes and T-waves).
190
,
191
Regarding exercise recommendations, participation in competitive sports may be
considered for short QT patients as long as they are asymptomatic, have been
under treatment for 3 months and precautionary measures are taken (automatic
external defibrillator).
Recommendation grade: IIa.
Evidence level: C.
5.4. Brugada Syndrome
This syndrome is characterized by the occurrence of syncope or SD caused by
polymorphic ventricular tachycardia in structurally normal hearts. Its diagnosis
may be based on a specific EGC pattern, defined as an ST-segment elevation
≥ 2mm (0.2 mV) in the right precordial leads. However, this diagnosis may
be unstable.
192
Its most
peculiar aspect is J-spot elevation in the right precordial leads (V1 to V3),
although this phenomenon has also been described in lower leads.
193
-
195
However, the ECG results may
be unimpressive, requiring the use of sodium channel blockers to unmask the
condition. The tracking and proper identification of these patients are
essential, since SD is rarely the first symptom.
192
This syndrome is highly influenced by gender, since 90% of cases occur in men. To
date, only functional loss mutations in SCN5A, present in about 20% of those
affected, have been identified. Currently, a total of 23 genes have been
implicated in Brugada syndrome (BrS1-BrS23), and the vast majority of them are
very rare.
196
Clinically, the
disease manifests with syncope or SD, predominantly in the third or fourth
decade of life, with fever as a trigger for arrhythmias.
In risk stratification, individuals with spontaneous J-point elevation have a
worse prognosis than those in whom the typical pattern was observed only after
infusion of flecainide, procainamide or ajmaline. The occurrence of syncope,
associated with spontaneous J-point elevation, increases the risk of SD by up to
6 times. Neither a family history of SD nor detecting a mutation in the SCN5A
gene proved useful for risk stratification.
197
,
198
Sports have not been described as a SD risk factor in Brugada syndrome. However,
since there is a greater risk of events related to parasympathetic activity in
this syndrome, arrhythmias can occur after exercise/training, a point in which
there is vagal recovery and sympathetic withdrawal. In addition, significant
elevations in body temperature due to intense physical activity in unfavorable
environments may also trigger SD.
Defibrillators are recommended for:
Aborted SD patients.
Recommendation grade: I.
Evidence level: B.
Patients with spontaneous J-point elevation and syncope, or with previously
documented ventricular tachycardia.
Recommendation grade: IIa.
Evidence level: B.
Exercise and competitive sports may be considered for Brugada patients, provided
they are asymptomatic and have been undergoing treatment for 3 months.
Recommendation grade: IIa.
Evidence level: C.
5.5. Catecholaminergic Polymorphic Ventricular Tachycardia
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is triggered by
physical exertion or emotional stress in children and young adults with
structurally normal hearts.
199
,
200
The patient's resting ECG will appear normal, except
for relative bradycardia for age and frequent U-waves. The disease manifests
clinically as syncope.
199
At least four mutations have been described in several genes (RyR2, CASQ2, TRDN,
CALM1) that potentially cause CPVT. The most common cause is functional gain
mutation in RyR2 (about 60% to 75% of cases), the gene that encodes type 2
ryanodine receptor, which is the protein responsible for releasing calcium from
the sarcoplasmic reticulum. Anomalies in the CASQ2, the gene that encodes
cardiac calsequestrin, which is a calcium-binding protein in the sarcoplasmic
reticulum, account for up to 5% of CPVT cases. The CALM1 gene encodes
calmodulin, a protein that binds to calcium and stabilizes the RyR2 channel, and
accounts for less than 1% of the cases. Finally, there is also the TRDN gene
(identified in two families with CPVT), which encodes triadin, a protein that
binds RyR2 and calsequestrin to the sarcoplasmic reticulum.
201
-
203
Genetic analysis does not
contribute to risk stratification, but it is important for identifying mutation
carriers that have not yet manifested symptoms. The initial presentation of
about 30% of patients is SD, and up to half of the patients suffer cardiac
arrest between the ages of 20 and 30 years.
204
CPVT is a penetrating disease, and the prevalence of
"silent" cases could be up to 20%.
205
However, cardiac events may occur even in this
subgroup of individuals, who should be treated according to current guidelines.
In these cases, genetic analysis plays a central role.
206
,
207
Arrhythmias during exercise are the typical manifestation, frequently 120 to 130
beats per minute, beginning with isolated ventricular extrasystoles and
progressing to episodes of unsustained and sustained ventricular tachycardia if
effort is continued, usually with 180° rotation in the front plane
(bidirectional). Atrial arrhythmias, atrial fibrillation and supraventricular
tachycardia are also common in the syndrome. Beta-blockers, the main therapeutic
pillar for CPVT,
208
,
209
are very effective and are recommended for:
Patients with clinical manifestations.
Recommendation grade: I.
Evidence level: B.
Asymptomatic mutation carriers.
Recommendation grade: IIa.
Evidence level: B.
An ICD is recommended for individuals with aborted SD.
Recommendation grade: I.
Evidence level: B.
Individuals with sustained syncope or ventricular tachycardia despite the use of
beta-blockers.
Recommendation grade: IIa.
Evidence level: B.
Recommendations about competitive sports in this disease are quite restrictive:
athletes with symptomatic or asymptomatic CPVT should not participate in
competitive sports (except class IA).
Recommendation grade: III.
Evidence level: C.
6. Athletes with Valvular Heart Disease
6.1. Introduction
The assessment and follow-up of physically active individuals with valve disease
are important pillars of sports cardiology. For athletes with valvular heart
disease, eligibility criteria are based on cohort studies and expert consensus.
However, randomized clinical trials with prospective data are scarce.
Athletes with intermediate degrees of valve disease are the most challenging
group. Serial evaluation and stratification of disease severity are fundamental.
As new symptoms develop, they should be treated promptly.
To qualify for competition, athletes must initially be classified according to
symptoms, degree of valvular damage and left ventricular dysfunction.
Stage A: Asymptomatic athletes at risk of developing stenosis or significant
valve regurgitation, e.g., mitral valve prolapse or BAV, as well as individuals
whose physical examination is consistent with the underlying pathology (mitral,
aortic ejection), but not classic valve dysfunction.
Stage B: Asymptomatic athletes with mild-to-moderate valve disease with preserved
LV function.
Stage C: Asymptomatic athletes with severe valve disease with preserved LV
systolic function (C1) or LV systolic dysfunction (C2).
Stage D: Symptomatic athletes with severe valve disease (with or without LV
dysfunction).
6.2. Aortic Valve Disease
Aortic impairment is usually degenerative and is a result of aortic stenosis in
middle-aged/elderly athletes and BAV in younger athletes. In Brazil, rheumatic
etiology should be considered. Primary aortic diseases are common causes of
aortic regurgitation, although there are also rheumatic and congenital causes
(e.g., BAV).
210
,
211
6.2.1. Aortic Stenosis
Aortic stenosis is considered a progressive disease and survival during the
asymptomatic phase has been found similar to that of age-matched
controls.
212
In
2010, approximately 40 million people worldwide aged 65 or older had aortic
stenosis, and this number is expected to reach 72 million by 2030.
213
Lower exercise
tolerance, effort dyspnea, and angina in athletes with systolic murmur are
suggestive of clinically important aortic stenosis. Dyspnea is due to
increased LV filling pressure or an inability to increase cardiac output
with exercise.
Aortic stenosis is also recognized as responsible for SD in young athletes,
although the prevalence of less than 4%.
214
It is important to point out that almost
70% of SD episodes in subjects with severe aortic stenosis were not preceded
by any of the classic symptoms of the disease.
212
Echocardiography with Doppler color flow mapping is the method of choice for
diagnosis, classification and evaluation of aortic stenosis
215
(Table 11).
Table 11
Aortic stenosis severity rating
Impairment (degree)
Jet velocity (m/s)
Medium gradient (mmHg)
Aortic valve area (cm2)
Mild
< 3
< 25
> 1.5
Moderate
3-4
25-40
1.0-1.5
Severe
> 4
> 40
< 1.0 (< 0.6
cm2/m2)
Transthoracic echocardiography provides evidence of aortic valve anatomy
(e.g., the number of cusps and the extent of calcification), as well as
valve hemodynamics (to confirm severity) and their consequences on LV
function. Pulmonary hypertension, concomitant valvular disease and aortic
root dilation can also be evaluated.
216
Cardiac MRI is useful for patients with an unfavorable transthoracic window
and/or when there is disagreement between two-dimensional echocardiographic
parameters.
217
Computed tomography of the heart can be used to quantify valve
calcification. A calcium score of less than 700 Agatston units excludes
severe aortic stenosis and has a high negative predictive value. On the
other hand, scores over 2,000 Agatston units suggest severe aortic
stenosis.
213
Due to potential progressive aortic valve narrowing, athletes with mild or
moderate (stage B) aortic stenosis should be assessed annually.
In asymptomatic or oligosymptomatic patients, exercise testing (exercise
stress testing or CPET) could reveal those with low functional capacity,
intraoperative hypotension and/or electrocardiographic changes during
exercise. Such findings will conflict with the recommendations about sports
participation. Recently, Saeed et al.
218
analyzed almost 800 exercise tests and found that
patients with moderate-to-severe asymptomatic aortic stenosis can perform
the test safely and with good tolerability. In addition, event-free survival
at 1 year was almost 90% in asymptomatic patients, but less than 70% in
those who reported symptoms during exercise.
BAV patients without stenosis (stage A) should have an annual physical
examination to detect new heart murmurs. Athletes with mild-to-moderate
aortic stenosis (stage B) should undergo anamnesis, a physical examination,
echocardiography (to evaluate disease progression), and exercise testing to
ensure that their exercise tolerance is compatible with their physical
activity, that no episodes of hypotension occur during exercise, and that
there is no electrocardiographic evidence of complex
ischemia/arrhythmia.
6.2.1.1. Recommendations and Evidence Level
Athletes with aortic stenosis should be evaluated annually to continue
participating in sports.
Recommendation grade: I.
Evidence level: C.
Athletes with discrete aortic stenosis (stage B) and an appropriate
physiological response to a maximal exercise testing may participate in
any sport.
Recommendation grade: IIa.
Evidence level: C.
Athletes with moderate aortic stenosis (stage B) can participate in
competitive sports with low-to-moderate static and dynamic components
(classes IA, IB and IIA) if the exercise testing results are sufficient
for the activity level required in competition, with clinical,
hemodynamic and ECG responses to exercise and without ventricular
tachyarrhythmias.
Recommendation grade: IIa.
Evidence level: C.
Asymptomatic athletes with severe aortic stenosis (stage C) should not
participate in competitive sports, except for those with low static and
dynamic components (class IA).
Symptomatic athletes with aortic stenosis (stage D) should not
participate in competitive sports.
Recommendation grade: III.
Evidence level: C.
6.2.2. Aortic Regurgitation
The prevalence of aortic regurgitation increases with age, although it is
very low (1%) in individuals less than 70 years of age. After that age, its
prevalence increases to over 2%.
219
In the native valve, aortic regurgitation may be
the result of abnormalities of the valve leaflets, the aortic root or both.
The main causes of aortic regurgitation are diseases that affect the aortic
ring or root without directly involving the aortic valve: BAV, connective
tissue genetic disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes),
inflammatory diseases (in particular syphilitic aortitis, Takayasu arteritis
and giant cell arteritis), rheumatic heart disease and hypertensive
dilation. In fact, so-called "idiopathic" aneurysms of the ascending aorta
have a genetic diagnosis in at least 30% of the cases.
210
,
219
Aortic regurgitation is
invariably well tolerated and asymptomatic for years; however, eccentric
hypertrophy progressively develops and LV systolic and diastolic volumes
increase, which could lead to LV systolic dysfunction.
Aortic regurgitation is diagnosed in asymptomatic athletes when physical
examination reveals wide arterial pulse pressure, a diastolic murmur in the
aortic area or Erb's point, or a systolic murmur related to increased
systolic volume. An echocardiogram is definitive for diagnostic confirmation
and classifying aortic regurgitation. With color Doppler echocardiography,
the size of the regurgitant jet and the flow convergence can be determined,
allowing the regurgitant orifice area to be calculated.
210
,
220
CMRI may be used as a complement to echocardiography when quantifying aortic
regurgitation. In fact, it has been reported that quantitative volume and
regurgitant fraction can be calculated with better reproducibility through
CRMI than echocardiography.
221
,
222
Because the pathophysiology of aortic regurgitation leads to LV dilation in
elite athletes, it must be differentiated from the physiological alterations
in athlete's heart syndrome. Therefore, when evaluating increased LV volume
in elite athletes with suspected or diagnosed aortic regurgitation, only LV
volumes that exceed normal physiological response to sports training should
be considered.
Although up to 45% of male athletes have a LV end-diastolic diameter (LVDD)
> 55 mm, only 14% of elite male athletes have a LVDD > 60 mm, and LVDD
rarely exceeds 70 mm. A LVDD > 55 mm occurs in < 10% of elite female
athletes, while only 1% have a LVDD > 60 mm.
223
-
225
The same is true for LV end-systolic
diameter (LVSD): in elite athletes, the upper limit for LVSD is 49 mm for
males and 38 mm for females. Only index data on body surface area and height
are available regarding LVDD, which indicate upper limits of 35.3
mm/m2 and 40.8 mm/m2 for male female athletes,
respectively.
223
-
226
A normal LV ejection fraction response to exercise is observed in aortic
regurgitation patients until there is significant LV dilation. When
evaluating the progressive effects of severe aortic impairment in athletes
with normal LV ejection fraction, serial analysis of LVSD is of great value.
The American Heart Association/American College of Cardiology define
preserved systolic function (stage C1) in patients with significant aortic
impairment as a LV ejection fraction ≥ 50% and LVSD ≤ 50 mm or
index LVSD ≤ 25 mL/m2.
210
,
227
Thus, in athletes with significant
aortic impairment and a LVDD that exceeds the above-mentioned reference
values. There is a higher probability that severe aortic impairment
contributes to LV dilation. Such athletes require a more careful evaluation
to verify that no ventricular increase has occurred and whether signs and/or
symptoms occur during exercise, such as dyspnea on exertion or reduced
functional capacity.
6.2.2.1. Recommendations and Evidence Level
Athletes with aortic regurgitation should be evaluated annually to
continue participating in sports.
To confirm that athletes with aortic regurgitation are truly
asymptomatic, they should undergo an exercise testing involving at least
the activity level achieved during training and competition and have a
physiological hemodynamic response.
Athletes with mild-to-moderate aortic impairment (stage B), a
physiological response to a maximal exercise testing, normal or
discretely dilated LV and a normal ejection fraction may participate in
any sport (with frequent reassessment).
Recommendation grade: I.
Evidence level: C.
Athletes with mild to moderate aortic regurgitation (stage B), a
physiological response to a maximal exercise testing, a moderately
dilated LV (LVSD < 50 mm [men], < 40 mm [women] or < 25
mm/m2 [both sexes]) and a normal ejection fraction may
participate in any sport (with frequent reassessment).
Recommendation grade: IIa.
Evidence level: C.
Athletes with severe aortic regurgitation (stage C1), a physiological
response to a maximal exercise testing, a moderately dilated LV (LVSD
< 50 mm [men], < 40 mm [women] or < 25 mm/m2 [both
sexes]), a normal ejection fraction and no progression of aortic
impairment or LV regurgitation according to echocardiography may
participate in any sport (with frequent reassessment).
Athletes with aortic regurgitation whose aortic diameters are 41 to 45 mm
may participate in sports in which there is no risk of collision (with
frequent reassessment).
Recommendation grade: IIb.
Evidence level: C.
Symptomatic athletes with significant aortic regurgitation (stage D), LV
systolic dysfunction with an ejection fraction < 50% (stage C2), LVSD
> 50 mm or > 25 mm/m2 (stage C2) or a significant
increase in LVDD (> 70 mm or ≥ 35.3 mm/m2 [men],
> 65 mm or ≥ 40.8 mm/m2 [women]) should not
participate in competitive sports.
Recommendation grade: III.
Evidence level: C.
6.2.3. Bicuspid Aortic Valve
BAV is the most common congenital heart disease, affecting 1.3% of the
population.
228
There is already consensus that an association exists between BAV and
changes in vascular connective tissue, and that dilation of the aortic root
can occur, including a risk of dissection, even in the absence of
hemodynamically significant aortic stenosis or aortic
regurgitation.
229
,
230
6.2.3.1. Recommendations
Athletes with BAV but not aortic root dilation (less than 40 mm, or
equivalent in children and adolescents according to body surface area),
significant aortic stenosis, or aortic regurgitation may participate in
any competitive sport.
Athletes with BAV and aortic root measurements between 40 and 45 mm may
participate in competitive sports with a low-to-moderate static
component or a low-to-moderate dynamic component (classes IA, IB, IIA
and IIB) but should avoid sports that involve a risk of collision or
trauma.
Athletes with BAV and aortic root dilation greater than 45 mm may
participate only in competitive sports with low static and dynamic
components (class IA).
6.3. Mitral Valve Disease
6.3.1. Mitral Stenosis
A mitral valve area of 4 to 6 cm2 is considered normal. Mitral
stenosis affects women twice as frequently as men.
231
As mitral stenosis progresses,
particularly when the area becomes smaller than 2 cm2, a
diastolic pressure gradient develops between the left atrium (LA) and the
LV, causing elevation in LA pressures and decreased flow towards the
LV.
232
Frequently
of rheumatic origin, mitral stenosis rarely causes SD. However, exercise may
lead to a marked increase in pulmonary and pulmonary capillary pressure,
sometimes culminating in acute pulmonary edema.
233
Athletes with mitral stenosis are more
likely to develop atrial fibrillation as a result of strenuous exercise in
an already enlarged atrium. Systemic embolization is the main complication,
but there is no evidence that strenuous exercise increases risk. When atrial
fibrillation occurs in an athlete with mitral stenosis, anticoagulant
therapy should be applied.
As in other valvular heart diseases, the evaluation of athletes with mitral
stenosis requires a well-documented anamnesis, as well as an echocardiogram
(Table 12).
215
This disease is
considered severe when there is a resting mean transmitral gradient of 5 to
10 mmHg, which is dependent on transvalvular flow and the diastolic filling
phase, factors that vary widely with increased heart rate during
exercise.
210
Table 12
Echocardiographic features of severe mitral stenosis
Mitral valve area < 1.5 cm2
Mean left atrial/left ventricular diastolic
gradient ≥ 10 mmHg
Pulmonary artery systolic pressure ≥ 50
mmHg at rest
Pulmonary artery systolic pressure ≥ 60
mmHg on effort
Athletes with mitral stenosis, whether asymptomatic or with minimal symptoms,
should perform an exercise testing involving at least the activity level
achieved during training/competition, especially if the disease severity is
uncertain. The intensity of physical activity should depend on the size of
the left atrium and the severity of the defect. Pulmonary artery systolic
pressure during exercise can be estimated noninvasively with an
echocardiogram, which can be of great value in quantitative analysis of the
safe training range for mitral stenosis patients.
210
6.3.1.1. Recommendations and Evidence Level
Athletes with mitral stenosis should undergo an annual evaluation to
continue participating in sports.
An exercise testing should be performed involving at least the activity
level achieved during training/competition with a hemodynamic response
to confirm the symptom status.
Recommendation grade: I.
Evidence level: C.
Athletes with mild mitral stenosis (mitral valve area > 2.0
cm2, mean gradient < 10 mmHg at rest) in normal sinus
rhythm may participate in any competitive sport.
Recommendation grade: IIa.
Evidence level: C.
Athletes with significant mitral stenosis should not participate in
competitive sports, with the possible exception of sports with low
static and dynamic components (class IA).
Athletes with any degree of mitral stenosis and atrial fibrillation or
who have a history of atrial fibrillation on anticoagulant therapy
should not participate in competitive sports involving collision/trauma
risk.
Recommendation grade: III.
Evidence level: C.
6.3.2. Mitral Regurgitation
The prevalence of mitral regurgitation is age dependent, with a frequency
> 6% in adults over 65 years of age.
234
The pathogenesis varies from mitral-valve prolapse
(sometimes with myxomatous degeneration) to rheumatic causes, connective
tissue diseases (e.g., Marfan syndrome) and infective endocarditis, to
secondary causes such as coronary artery disease and dilated cardiomyopathy.
Diagnostic suspicion arises from auscultating a systolic murmur at the apex,
which is confirmed and quantified by echocardiography.
220
Generally, athletes with
mild or moderate mitral regurgitation are asymptomatic (Stage B).
The severity of mitral regurgitation is related to LV regurgitant volume into
the left atrium, with increased atrial pressure, increased ventricular
diastolic volume and posterior LV dilation.
235
Due to overestimation of the LV ejection
fraction, LV systolic dysfunction in athletes with mitral insufficiency is
defined as a LV ejection fraction < 60% or LVSD > 40 mm. As in aortic
regurgitation, it is difficult to distinguish LV dilation due to exercise
from that caused by major mitral regurgitation when LVDD is < 60 mm (or
< 40 mm/m2). However, LVDD > 60 mm strongly suggests
significant mitral regurgitation, thus justifying subsequent
investigation.
210
Dynamic exercise generally decreases the regurgitant fraction due to reduced
systemic vascular resistance. On the other hand, static exercise with
increased systemic BP, HR and systemic vascular resistance increase
regurgitant volume, which increases the pressure in pulmonary capillaries.
The assessment of athletes with mitral regurgitation, which should occur at
least annually, should include complete anamnesis and an echocardiogram.
This test can noninvasively estimate pulmonary artery systolic pressure
during exercise and is useful for decision making about the intensity of
safe physical activity, especially in those with more severe mitral
regurgitation.
210
The recommendations listed below should be considered in patients with
secondary causes of mitral regurgitation (e.g., infective endocarditis,
rupture of the mitral valve chordae) due to a marked increase in LV systolic
pressure, which could further damage valve tissue.
6.3.2.1. Recommendations and Evidence Level
Athletes with mitral regurgitation should be evaluated annually to
continue participation in sports.
Athletes with mitral regurgitation should undergo an exercise stress
testing or CPET involving at least the activity level achieved in during
training and competition, with a hemodynamic response to confirm symptom
status.
Athletes with mild-to-moderate mitral regurgitation, normal sinus rhythm,
normal LV diameter and function, and normal pulmonary arterial pressures
(stage B) may participate in any competitive sport.
Recommendation grade: I.
Evidence level: C.
Athletes with moderate mitral regurgitation (stage B), normal sinus
rhythm, normal LV ejection fraction, and moderate LV dilation
(compatible with that resulting exclusively from exercise [LVDD < 60
mm or < 35 mm/m2 in men or < 40 mm/m2 in
women) may participate in any sport.
Recommendation grade: IIa.
Evidence level: C.
Athletes with significant mitral regurgitation, normal sinus rhythm, a
normal LV ejection fraction at rest, and mild LV dilation (compatible
with that which can only result from exercise [LVDD < 60 mm or <
35.3 mm/m2 in men or < 40 mm/m2 in women])
(stage C1) may participate in sports with a low-to-moderate static
component and a low dynamic component, as well as in sports with a low
static component and a moderate dynamic component (classes IA, IIA and
IB ).
Recommendation grade: IIb.
Evidence level: C.
Athletes with mitral regurgitation and significant LV dilation (LVDD
≥ 65 mm or ≥ 35.3 mm/m
2
[men] or ≥ 40 mm/m
2
[women]), pulmonary
hypertension and LV ejection fraction < 60% or LVSD > 40 mm should
not participate in any competitive sport, with the possible exception of
low static and dynamic component sports (class IA).
Athletes with mitral regurgitation and a history of atrial fibrillation
and long-term anticoagulation therapy should not participate in sports
that involve a risk of collision/trauma.
Recommendation grade: III.
Evidence level: C.
6.3.3. Mitral-Valve Prolapse
This pathology, which has an estimated prevalence of 2% to 4% in the general
population, appears to be more common in women. Diagnosed with
echocardiography, it is defined as systolic displacement of one or both
mitral leaflets ≥ 2 mm into the left atrium, as well as by the mitral
annular plane in the parasternal cross-section of the long axis.
235
,
236
It occurs in two forms:
the classical form, with diffusely thickened leaflets (≥ 5 mm) with
bileaflet prolapse; or the non-classical form, in which there is limited
(< 5 mm) or absent thickening and segmental prolapse. Classical prolapse
can be further subdivided into symmetrical (when the leaflets meet at a
common ring point) and asymmetrical (when one leaflet is moved further
towards the atrium).
237
A
mitral valve leaflet thickness > 5 mm in the echocardiogram has been
associated with an increased risk of SD, stroke and endocarditis in patients
with classic prolapse.
236
The etiology can be primary (degenerative disease) or secondary (Marfan
syndrome, Ehlers-Danlos syndromes, pseudoxanthoma elasticum). These patients
can be identified through auscultation by the presence of a
meso-telesystolic click and/or a mitral regurgitation murmur, as well as by
chest pain, dyspnea, exercise intolerance, syncope and/or dizziness.
The major risks related to mitral-valve prolapse include severe progressive
mitral regurgitation requiring valve surgery, infective endocarditis,
embolic events, atrial and ventricular tachyarrhythmias and SD (which
appears to be associated with structural abnormalities of the mitral valve,
as in the classical form), with diffuse thickening, stretching and
redundancy, and, in some cases, rupture of chordae tendineae.
The prognosis for mitral-valve prolapse is controversial. For example, the
Framingham Heart Study
238
described mitral-valve prolapse as a benign entity, but other studies
indicate that a subgroup of patients may be at a greater risk of cardiac
arrest, which is the most devastating consequence. Thus, the risk for
serious adverse events secondary to mitral-valve prolapse remains
uncertain.
239
,
240
SD associated with isolated mitral-valve prolapse is rare among young people,
particularly with respect to exercise, and is also rare among professional
athletes: its frequency in these groups is no greater than that of the
general population. It predominantly occurs in patients over 50 years of age
with severe mitral regurgitation and/or systolic dysfunction. However, Basso
et al.
241
have shown a
growing interest in mitral-valve prolapse, highlighting this entity as a
neglected cardiac abnormality that could be associated with severe cardiac
events, including SD in youth and adults. Caselli et al.
242
evaluated a large cohort
of competitive athletes from 2000 to 2010, finding that mitral-valve
prolapse was a relatively common finding, although predominantly benign. In
addition, they recommend that detecting moderate-to-severe mitral
regurgitation, as well as ventricular arrhythmias, may be useful for
identifying athletes with mitral-valve prolapse who are at greater risk.
Some individuals with mitral-valve prolapse present a phenotype described as
MASS (mitral valve, aorta, skeleton, and skin), which involves connective
tissue changes, long limbs, deformity of the thoracic cage, and joint
hypermobility). In such patients the risk of progression to aortic
dilation/dissection or SD is greater. The MASS phenotype only applies if the
aortic diameter z-score is < 2, the systemic score is ≥ 5 and the
patient is at least 20 years old.
243
-
246
6.3.3.1. Recommendations
Athletes with mitral-valve prolapse but no prior syncope (especially if
of arrhythmogenic origin), sustained supraventricular or unsustained
tachycardia or complex ventricular tachycardia according to 24 h Holter
monitoring, severe mitral regurgitation according to an echocardiogram,
LV systolic dysfunction (LV ejection fraction < 50%), previous
embolic event or family history of SD related to mitral-valve prolapse
may participate in any competitive sport.
Athletes with mitral-valve prolapse who exhibit any of the above
characteristics may participate in competitive sports with low static
and dynamic components (class IA).
Recommendations for athletes with mitral-valve prolapse and hemodynamic
overload secondary to moderate-to-severe mitral regurgitation should be
guided by the mitral regurgitation.
6.3.4. Tricuspid Stenosis
In isolation, tricuspid stenosis is rare. It is mainly caused by rheumatic
disease and is usually associated with mitral stenosis. Although less
common, tricuspid stenosis may result from congenital/genetic abnormalities,
such as Ebstein's anomaly, Fabry disease, Whipple disease, or active
infective endocarditis.
247
In summary, tricuspid stenosis patients should be
considered according to degree of severity (Table 13).
215
Table 13
Echocardiographic features of severe tricuspid stenosis
Tricuspid valve area ≤ 1.0
cm2
Mean diastolic gradient right atrium/right
ventricle ≥ 5 mmHg
Isolated right atrial enlargement
Tricuspid pressure half-time ≥ 190 ms
6.3.4.1. Recommendations
Asymptomatic athletes may participate in any competitive sport. An
exercise testing involving at least the activity level achieved during
training and competition should be performed.
6.3.5. Tricuspid Regurgitation
Tricuspid regurgitation is reported as the most common heart valve disease,
affecting up to 85% of the population.
248
It is divided into two categories: primary (or
organic) and secondary tricuspid regurgitation, which is the most common
form. Namely, only 8% to 10% of tricuspid regurgitation cases are
primary,
246
being
associated with rheumatic heart disease, pacemaker electrode and
defibrillator leads (iatrogenic complications) myxomatous degeneration,
myocardial degeneration, tricuspid valve prolapse, infectious diseases
(e.g., endocarditis) and congenital heart diseases (e.g., Ebstein's
anomaly). It may also be related to postoperative complications. Physical
examination and chest X-ray may help estimate tricuspid regurgitation, but
echocardiogram is the gold standard for assessing the mechanism and severity
of the condition. Three-dimensional echocardiography is even more sensitive,
allowing a simultaneous view of all the leaflets.
249
If RV function cannot be adequately
evaluated with this method, CMRI, due to its capacity to quantify RV volumes
and ejection fraction, is an important introductory step.
248
If these measures cannot
be estimated/determined non-invasively, right cardiac catheterization is
used for such evaluation.
"Physiological" tricuspid regurgitation can be detected by echocardiography
in approximately 80% of healthy athletes and does not imply any structural
valve abnormality.
231
6.3.5.1. Recommendations
Athletes with primary tricuspid regurgitation, regardless of severity,
and normal RV function, in the absence of right atrial pressure > 20
mmHg or elevated RV systolic pressure, may participate in any
competitive sport.
6.3.6. Multivalvular Heart Disease
Multivalvular heart disease, a combination of stenotic and/or regurgitant
lesions of two or more heart valves, is a highly prevalent clinical
condition among patients with valvular heart disease. It occurrence is
mainly due to rheumatic heart disease, although the incidence of this
etiological factor has decreased dramatically in the last five
decades.
250
Myxomatous valvulopathy and infective endocarditis are also associated with
multivalvular disease. Diagnosis is through physical examination,
echocardiogram (the main imaging mode for diagnosis and follow-up), and
sometimes cardiac/coronary angiography.
6.3.6.1. Recommendations
The cumulative effects of multiple significant valve lesions on an
individual's physiological response to exercise may be difficult to
predict, and multiple moderate lesions may also have physiological
effects on the somatosensory system. Generally speaking, athletes with
moderate-to-severe multivalvular disease should not participate in
competitive sports.
6.4. Sports after Valve Surgery
Although much progress has been made in cardiac surgery, mortality after valve
replacement is still higher than that of the general population of the same age
group.
Mechanical heart valve prosthesis requires anticoagulant therapy and
transvalvular gradients of varying degrees, which could be exacerbated by
exercise. Thus, for athletes who have had a valve replacement, such factors
determine their adequacy for competitive sports.
251
An exercise stress testing or CPET involving at least at the activity level
achieved during training and competition is of great value for analyzing the
functional capacity of the athletes who have undergone valve
replacement/repair.
6.4.1. Recommendations and Evidence Level
Athletes with an aortic or mitral bioprosthesis who are not on anticoagulant
therapy and have normal LV ejection fraction and valvular function may
participate in competitive sports (class IA, IB, IC and IIA).
Athletes with an aortic or mitral mechanical heart valve prosthesis who are
undergoing anticoagulant therapy and have normal LV ejection fraction and
valvar function may participate in competitive sports (class IA, IB and IIA)
if there is no risk of collision/trauma.
Athletes who have undergone successful mitral balloon valvuloplasty or
surgical commissurotomy may participate in competitive sports based on the
severity of their residual mitral regurgitation or aortic stenosis and their
pulmonary arterial pressure during rest and exercise.
Athletes who have undergone mitral valve surgery to correct mitral
regurgitation or aortic valve repair, having no residual or moderate mitral
regurgitation and having normal LV ejection fraction, may participate in
sports (class IA, IB and IIA), but only at the discretion of the attending
physician and if there is no risk of collision/trauma.
Recommendation grade: IIa.
Evidence level: C.
6.4.2. Transcatheter Aortic Valve Implantation
Transcatheter aortic valve implantation is a minimally invasive percutaneous
procedure that was performed for the first time in 2002. It is considered
the gold standard for patients with aortic stenosis who are at high surgical
risk, especially older adults.
252
Since these patients often have low functional
capacity, therapeutic exercise intervention can improve their physical
integrity and performance in activities of daily living.
Several recent studies have confirmed the benefits of exercise in patients
who have undergone transcatheter aortic valve implantation. They are
unanimous in reporting improved functional capacity (as measured by CPET or
the 6-minute walk test).
253
-
256
Altisent et al.,
257
in a 4-year follow-up, found that an
increase < 20% in the 6-minute walk test 6 months after the procedure
correlates with an all-cause mortality of 65%. Therefore, exercise increases
the functional capacity of these individuals, improving prognosis and
quality of life. It should be pointed out that we are not aware of any
studies on athletes who have undergone transcatheter aortic valve
implantation.
7. Athlete's Heart Syndrome in Women
7.1. Introduction
Since the passage of Title IX in 1972, women's participation in sports has
increased dramatically. During the 2014-2015 school year, approximately 8
million United State. high school students participated in sports, over 40% of
whom were girls.
258
Female
athletes have been historically underrepresented in research that has guided
exercise and sports cardiology. However, in the last three decades there has
been an exponential increase in the number of women participating in competitive
sports. Thus, female gender should be considered an important biological
variable in this context.
As in men, the body of female athletes also undergoes physiological adaptations
to physical training and may present structural and electrical changes
compatible with athlete's heart syndrome. Such adaptations can occur in all
athletes, but their magnitude depends on several factors, including gender.
There are anthropometric, physiological and biochemical differences between men
and women, including smaller stature, lower body mass, smaller LV diameter, less
testosterone and a different physical work capacity.
259
In hemodynamic terms, higher resting HR have
been observed, although maximum levels during exercise are reached in a manner
similar to men. Systolic BP and systolic volume increase less on effort, and
maximal O2 consumption (VO2max) is lower. Nevertheless,
female cardiac output is 5% to 10% higher than that of males at any level of
submaximal oxygen consumption.
260
In absolute values, female work capacity is lower, but
when assessed at the same intensity percentage, the cardiovascular performance
of men and women are similar.
Since physical training can result in a series of cardiovascular system
modifications and adaptations, knowing how to differentiate physiological
responses due to regular exercise from pathological ones can be a challenge when
performing detailed clinical evaluations of athletes.
7.2. Complementary Exams
7.2.1. Twelve-Lead Electrocardiogram
7.2.1.1. Electrocardiogram: Physiological Changes vs. Changes
Suggestive of Heart Disease
Both physiological and pathological adaptations may differ between female
and male athletes in ECG. However, data on specific ECG differences
between genders are limited. Using the criteria of Pelliccia et al.
(2000),
261
women had a higher prevalence of normal ECG than men (78% vs. 55%) in a
cohort of European Olympic athletes. On the other hand, according to the
latest Seattle criteria,
262
no significant differences were observed between
genders (96% of males and 97% of females had normal ECG). This contrast
could be justified by the fact that the Seattle Criteria are much more
rigorous, which increases specificity without sensitivity loss.
Female athletes appear to have a lower prevalence of physiological
changes in ECG, especially regarding isolated increases in QRS complex
amplitude (in about 10% of women), incomplete RBBB and early
repolarization (four times less than men).
263
,
264
However, female
athletes had a higher frequency of QT interval increase, as well as
inverted T-wave in the V1-V2 leads (1% vs. 0.2% in male
athletes),
265
such findings are considered non-pathological adaptations. Inverted
T-waves in the inferior and/or lateral walls are more prevalent in male
athletes, being more commonly associated with underlying structural
heart disease.
266
On
the other hand, anterior precordial T wave inversion is more common in
women and, when limited to V1-V3 leads, does not appear to be related to
structural heart disease.
267
,
268
However, ventricular repolarization
changes in lateral leads are less common and should always serve as a
warning for a possible pathology.
269
One important point to consider is that the international guidelines for
interpreting ECG in athletes do not differ according to gender, but are
unanimous in stipulating a higher QTc interval cut-off point for women
than men, since women, regardless of cardiac remodeling, have longer QTc
intervals than men (≥ 480 ms vs. ≥ 470 ms,
respectively).
101
,
270
7.3. Echocardiogram
The echocardiogram is one tool available for PPS and determining sports
eligibility. In a study of 600 female athletes who participated in different
sports, it was found that the LV cavity is rarely greater than 54 mm (a
threshold value for normality in women) and never above 66 mm. The thickness of
the LV wall rarely measures over 11 mm, reaching a maximum of 13 mm, usually in
blacks.
225
,
271
Finocchiaro et al.
264
confirmed these findings: none of the women
in their sample had an LV wall thickness > 12 mm, and only 7% had a LV
end-diastolic diameter > 54 mm. In fact, these results are clinically
relevant, since a LV cavity < 54 mm can distinguish, for example, an
"athlete's heart" from HCM with excellent sensitivity and specificity.
272
It has long been known that one adaptation to regular physical training is
increased LV mass, observed mainly in endurance athletes. However, when LV wall
thickness is accompanied by a reduction in cavity size, a pathological process
such as HCM should be suspected. LV wall thickness > 12 mm in men or > 10
mm in women is considered abnormal in white athletes, and further investigation
is necessary.
273
In black
athletes, an LV wall thickness of 11 mm can be observed, which can reach up to
12 or even 13 mm in exceptional situations.
271
Since none of the athletes Finocchiaro et al.'s sample
had a LV wall ≥ 13 mm, it would be reasonable to infer that an LV wall
thickness of 13 mm probably represents the upper physiological limit of LV
hypertrophy in black and asymptomatic athletes where there is no family history
of HCM.
Recent experiments have demonstrated that women with "athlete's heart" have
eccentric LV hypertrophy. Initially, there is an increase in the cavity which,
although smaller (5%) than that of a man, is larger when indexed to body
surface. LV wall thickness and LV mass do not increase proportionally, being
smaller than those of male athletes (23% and 31%, respectively). It is suggested
that a relative LV wall thickness > 0.48 is a marker of pathology.
269
D'Ascenzi et al.
274
investigated the morphology and function of the left and right atria in
competitive volleyball athletes, observing a biatrial increase with normal
filling pressures and low complacency. In women, these characteristics are
typical of athlete's heart and should be thus interpreted as a physiological
adaptation to intense physical training.
7.4. Exercise Testing
Prior to this decade, the exercise stress testing was considered less accurate
when diagnosing CAD in women. However, more recent studies have vindicated its
effectiveness, especially for variables besides ST-segment. Women are more
likely to have baseline ST-segment and T-wave changes, as well as ST-segment
depression, during exercise. This is believed to be a consequence of a
"digoxin-like" estrogen effect, since the changes seem to vary according to
menstrual cycle and postmenopausal hormone replacement.
275
Unlike men, ST-segment
change in asymptomatic women does not correlate with mortality. In many
circumstances, due to the relatively higher prevalence of false-positive traits
in women, those with ST-segment depression generally receive non-cardiac
diagnoses, with no additional exams or subsequent cardiac treatment.
276
In men and women, a chronotropic index < 0.8 and HR recovery < 12 bpm after
the first minute correlate with increased mortality and are valuable measures
for prognostic evaluation.
Functional capacity, obtained though the exercise stress testing, is especially
useful for athletes, besides being an independent predictor of CAD and
mortality. For accurate evaluation of exercise capacity, as well as for training
adjustments, an association of exercise ECG and expired gas measurements (CPET)
is recommended.
259
Recommendation
Recommendation grade
Evidence level
Exercise stress testing in initial assessment for
competition or a series of tests for training load
adjustment
IIb
B
CPET (previous item)
IIa
B
CPET: cardiopulmonary exercise testing.
7.5. Sudden Death
Curiously, the occurrence of SD differs between male and female athletes. Several
types of evidence indicate that SD is overwhelmingly more prevalent in male
athletes.
277
-
280
This disproportional occurrence would seem to suggest
that women have some "protective factor" against heart disease, in whom SD is
less likely than men under similar conditions. However, little is known about
other factors that could be decisive in this outcome. Moreover, it has been
shown that 92% of young athletes with SD were men, and that only 53% of women
had some structural change.
281
The proportion of women among master athletes (> 40 years of age) has grown.
There has been much discussion about whether intense exercise over a period of
many years has deleterious effects. Myocardial fibrosis, atherosclerotic
plaques, and a higher incidence of atrial fibrillation have been found in some
groups of athletes.
282
However, whether the additional risk from very intense exercise applies equally
to men and women has also been questioned. A recent meta-analysis involving more
than 149,000 women
283
found
that moderate exercise reduces the chance of developing atrial fibrillation,
especially in comparison to sedentary women, and that women who exercised
intensely on a regular basis had a 28% lower risk of atrial fibrillation. In
contrast, a prospective study suggested that the risk of atrial fibrillation in
women followed the same pattern as in men.
284
According to this study, the risk in more active women
was higher than in moderately active women and similar to that of sedentary
women. Thus, further investigation is necessary to better understand the
relationship between exercise and atrial fibrillation in women.
8. Basic Life Support for Athletes
8.1. Sudden Death among Athletes
Although rare, SD at a sporting event causes a public commotion, especially when
involving elite athletes. Statistics show that in the general population the
incidence of SD during exercise is approximately 0.46 cases per 100,000
person-years.
285
In
young athletes this incidence is also low: (a) 0.5 for every 100,000
person-years among athletes in Minnesota; (b) 2.3 per 100,000 person-years among
competitive athletes in northern Italy;
7
(c) 1 to 3 for every 100,000 person-years in
professional American football players.
286
However, the true incidence of cardiac SD in athletes
still requires further investigation. More recently, Emery and Kovacs
144
pointed out that the studies
estimating these events vary methodologically, diverging between the number of
athletes who suffered SD (numerator) and the number of athletes at risk
(denominator). In addition, some included only events that resulted in death,
while others also included those who survived cardiorespiratory arrest.
Several structural and non-structural changes (channelopathies) are responsible
for most cases of cardiac arrest among athletes. Studies conducted in the 1990s
pointed to HCM as the main cause of SD,
287
,
288
and data from another experiment conclusively showed
that HCM is the main cause of SD in young athletes, accounting for 26% of
cases.
289
Nevertheless, a meta-analysis of retrospective cohort studies, registries, and
autopsy series by Ullal et al.
290
challenged these conclusions: in more than 4,000 young SD
victims, structurally normal hearts were the most common findings (26.7%).
Interestingly, the proportion of HCM was much lower among their sample (10.3%).
Irrespective of these controversies, however, vigorous exercise, when associated
with heart disease, appears to trigger malignant events.
PPS generally consists of a detailed history, a physical examination and resting
12-lead ECG, although whether ECG should be mandatory has been debated in the
international scientific community.
5
An important Italian study showed that mandatory ECG use
reduced the annual incidence of cardiac SD by 90%.
291
The American Heart Association/American
College of Cardiology question the cost-effectiveness of this strategy, the high
rate of false-positive results, and the availability of qualified personnel to
interpret the results.
292
On
the other hand, the European Society of Cardiology recommends ECG for
PPS.
35
Regardless of
this controversy, PPS cannot eliminate SD among athletes. Thus, a second pillar
must be further developed: basic life support.
8.2. Initial Care for Athletes
The basic emergency care strategy can be summarized as a set of actions taken in
the first few minutes following a sudden cardiac event: (1) the organization and
planning of an emergency response team at the activity site; (2) training first
responders in cardiopulmonary resuscitation and AED use. Places where sports
activities occur (e.g., training centers, schools, colleges, gymnasiums, etc.)
must have a well-organized emergency care plan, including personnel trained in
basic life support and fast and effective communication with emergency services
who can perform advanced cardiac life support.
Effective treatment for an athlete who has suffered sudden cardiorespiratory
arrest depends on a sequence of interdependent actions that, when linked
together, form a chain reaction that increases the victim's chance of survival.
The American Heart Association calls this a "chain of survival" that consists of
the following links: rapid access, early cardiopulmonary resuscitation, early
defibrillation and early advanced cardiac life support .
Most sudden cardiorespiratory arrest in athletes is due to tachyarrhythmia
(ventricular fibrillation),
293
and can be treated with immediate defibrillation and
cardiopulmonary resuscitation (CPR). Reducing mortality among athletes who have
suffered sudden cardiorespiratory arrest requires CPR training programs and AED
use, as well as personnel who can recognize emergencies, activate the emergency
system, provide quality CPR, and use an AED. Current guidelines for sports
facilities require the installation of strategically placed defibrillators in
those with more than 2,500 patrons or those that host activities for individuals
in certain at-risk groups (e.g., heart disease patients or older
adults).
294
,
295
It is a well-established fact that for each minute without CPR, the
cardiorespiratory arrest victim's chance of survival decreases from 7% to 10%.
However, regarding structural diseases, ventricular arrhythmias appear to be
more susceptible to minor delays in defibrillation than structurally sound
hearts,
296
which
might explain why the survival rate of athletes declines more significantly when
AED use is delayed. This highlights the extreme importance of early
defibrillation, the third link in the chain.
Numerous studies have documented increased survival rates due to programs
promoting public access to defibrillation, including locations such as
casinos,
297
airports
298
and
airplanes.
299
If
resuscitation is delayed until the arrival of emergency services, survival rates
are very low, around 1 to 2%.
300
The use of AED in public places has led to survival rates
of up to 74% for out-of-hospital cardiac arrests.
301
However, due to the rarity of such events
among athletes, little is known about this initiative's specific impact on
them.
An important risk marker, PPS should be mandatory, since it can detect
cardiovascular changes that predispose an athlete to SD. Despite differing
international recommendations, there is consensus that the assessment of every
athlete should include clinical history, a physical examination and 12-lead ECG,
being complemented with other exams according to the degree of suspicion.
Athletes who experience SD require immediate high-quality cardiopulmonary
resuscitation to provide vital blood flow to the brain and heart. Defibrillation
should be performed, ideally, 3 to 5 minutes after collapse to increase the
chance of success. If, as in most cases, the post-shock rhythm cannot achieve
effective perfusion, CPR should be restarted immediately.
Finally, periodic medical evaluation, an effective local emergency protocol, and
personnel trained in basic life support can ensure high-quality CPR and early
defibrillation. This, plus quick access to centers with advanced cardiac life
support are fundamental for decreasing the number of SD cases in athletes and
increasing their chance of survival.
8.3. Special Aspects in Preventing Exercise/Sports-Related Sudden
Death
8.3.1. Doping: Illicit Substances in Sports
Some substances used for doping can have deleterious repercussions especially
on the cardiovascular system, including SD. Among the most commonly used
substances, we highlight anabolic steroids, ephedrine and amphetamines.
Among recreational drugs, we will address the use of cocaine and 3,
4-methylenedioxymethamphetamine, also known as ecstasy.
8.3.1.1. Anabolic Steroids
Anabolic steroids cause a number of side effects, including undesirable
cardiovascular effects. Anabolic steroids can induce secondary
hypertension and nephrosclerosis. Testosterone may increase the vascular
response to norepinephrine and, as a consequence, promote fluid
retention and elevated peripheral vascular resistance, leading to
increased blood pressure.
Tagarakis et al.
302
were the first to describe another important effect of steroids at the
microscopic level: the adaptation of cardiac capillaries and myocytes to
concomitant steroid use and physical training, which leads to a
disproportionate increase of in myocardial mass in relation to the
cardiac capillaries. The results of this study suggest that anabolic
steroids could cause an imbalance between oxygen supply and consumption,
especially during exercise. Recently, it has been shown that the
long-term administration of nandrolone decanoate to rats affects the
physiology of the cardiac autonomic system, resulting in a greater
predisposition to cardiovascular risk and SD. In addition, discontinued
usage did not result in an immediate return to normality.
303
In humans, anabolic
steroids may be associated with a shortened QT interval, thus negatively
impacting cardiac electrical activity.
304
In addition, indiscriminate use of
anabolic steroids seems to be an independent risk factor for morbidity
and premature death.
305
8.3.1.2. Ephedrine
In general, stimulants lead to tachycardia and increased myocardial
oxygen consumption, which may lead to arrhythmias and acute myocardial
infarction in susceptible individuals. Ephedrine may cause symptomatic
ventricular tachycardia, frequent ventricular extrasystoles, atrial
fibrillation, and SD. It is important to point out that many products
called "natural" or "herbal" contain ephedrine-like substances that go
unmentioned in the product description.
8.3.1.3. Amphetamines
Amphetamines are the prototype central nervous system stimulants. They
come in a great variety of formulas and presentations, with the most
commonly used being dextroamphetamine sulfate. This substance directly
stimulates adrenergic receptors at the cortical level and the ascending
reticular activating system, and its indirect action includes displacing
endogenous catecholamines from their sites in nerve endings. Its most
pronounced general side effects are insomnia, dizziness, profuse
sweating, tremors and euphoria; the cardiovascular effects are
palpitations, tachycardia and precordial discomfort; cerebral hemorrhage
is the neurological effect.
8.3.1.4. Cocaine
Cocaine causes generalized vasoconstriction, with the main consequence
being hypertension. Although cocaine use causes more intense
vasoconstriction in the central nervous system, it can also affect other
organs such as the kidneys, resulting in glomerular, tubular, vascular
and interstitial changes that lead to renal damage.
306
,
307
Cocaine may also cause acute
myocardial infarction, cardiac arrhythmias, congestive cardiomyopathy,
myocarditis, subarachnoid hemorrhage, aortic rupture, rhabdomyolysis,
arterial hypertension, spontaneous or exercise-induced myocardial
ischemia, and cardiac SD.
8.3.1.5. Ecstasy
Ecstasy is a hallucinogen similar to amphetamine. Due to its low cost and
availability in tablet form, its popularity and consumption have
increased significantly. Ecstasy increases the release of serotonin,
dopamine and norepinephrine by presynaptic neurons. It also prevents the
metabolism of these neurotransmitters by inhibiting monoamine oxidase.
Its main cardiovascular effects are hypertension, tachycardia and
arrhythmias, which can lead to SD.
308
-
310
8.4. Evaluating Athletes and the Organization and Planning of Emergency
Care
Sports-related SD is a dramatic event, and some measures can (and should) be
taken by doctors to try to prevent this rare but tragic complication of
sports/exercise.
8.4.1. Aspects Related to the Athlete
8.4.1.1. Pre-participation Screening
Considering that, in most cases, sports-related SD is caused by known or
undiagnosed heart disease, everyone who intends to participate in sports
should undergo PPS, regardless of age. This clinical examination should
be preceded by a thorough anamnesis with particular attention paid to
family history of cardiovascular disease and SD.
PPS, in attempting to detect these pathologies, is the most efficient way
to prevent a fatal cardiovascular event.
311
In 2009, the International Olympic
Committee published a paper on the importance of periodic medical
evaluation in elite athletes.
312
,
313
Although isolated clinical examination may fail to detect all forms of
heart disease with the potential to cause SD, this procedure, whose
emphasis on examining the cardiovascular system is preceded by a
thorough anamnesis and previous pathological history (including family
history), is nevertheless the first step in proper evaluation of the
athlete.
The clinical examination should ideally include a resting 12-lead ECG.
Although there is disagreement between U.S. (who recommend only
anamnesis and physical examination) and European authorities (who
recommend adding 12-lead ECG to anamnesis and clinical
examination),
314
the Brazilian Society of Cardiology considers
12-lead ECG as mandatory at the first cardiological
examination.
315
Resting ECG can diagnose numerous heart diseases
that can lead to SD, including long QT syndrome,
316
Brugada
syndrome,
193
Wolf-Parkinson-White syndrome
317
and HCM.
318
The European protocol, which includes
anamnesis, physical examination and ECG, is currently used by the
International Olympic Committee, the Italian Olympic Committee, FIFA and
the Union of European Football Associations.
292
,
319
,
320
The clinical examination should
include family and personal history and specific screening for Marfan
syndrome.
312
A more detailed approach to PPS is available in another section of this
Guideline.
8.4.1.2. Regarding the Athlete's Preparation
Follow-up for athletes must be thorough. To prevent clinical and
cardiovascular events, basic preventive measures, such as adequate
nutrition and hydration are also important, respecting rest periods and
avoiding training and competition during the hottest periods of the day.
Athletes in training and competition must be monitored and observed by
qualified medical staff, preferably who have experience in sports
medicine and first aid in case of emergency.
8.4.2. Aspects Related to Training Venues and Competition
8.4.2.1. Emergency Care and Medical Contingency Planning
In addition to procuring the necessary equipment for cases of
cardiorespiratory arrest, training and competition venues should develop
a medical contingency plan that includes personnel trained in
cardiorespiratory resuscitation and optimized transport to a hospital
with advanced cardiac life support when applicable.
286
,
321
8.4.2.2. Automatic External Defibrillators
The AED is a computerized device that can identify the occurrence of
ventricular fibrillation and tachycardia, the cardiac abnormalities that
respond to shock. These devices should be available for use in less than
5 minutes at training venues and competitions, clubs, arenas, stadiums,
gyms and cardiovascular rehabilitation clinics, which should also have a
team trained in cardiopulmonary resuscitation.
145
,
322
Among young athletes, CPR arrest usually occurs after intense training
sessions or during a competition. Although the occurrence of these
events is rare (corresponding to 1% of those occurring in middle-aged or
older adults), prompt care and successful resuscitation increase
long-term survival.
323
,
324
Related collections
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