Introduction
Patients with incessant ventricular tachycardia (VT), sustained VT despite treatment
with antiarrhythmic drugs, or shocks from implantable defibrillators are candidates
for catheter ablation (CA).1, 2, 3 Although ablation can be efficacious, mortality
is higher in patients with structural heart disease owing to hemodynamic instability
from anesthesia and arrhythmia induction.
1
,
3
,
4
The PAINESD risk score helps to identify patients at risk of acute hemodynamic decompensation,
permitting selection of those likely to benefit from intraprocedural mechanical circulatory
support (MCS).
5
In patients at high risk, temporary MCS, including percutaneous left ventricular (LV)
assist devices (pLVADs) and venoarterial extracorporeal membrane oxygenation (VA ECMO)
facilitates CA while reducing end-organ hypoperfusion, hemodynamic collapse, and worsening
heart failure.
6
,
7
As mapping patients in VT may not be tolerated for extended duration, substrate-based
ablation methods have been developed as a complement or alternative to activation
and entrainment mapping.
8
High-density mapping catheters, such as the HD Grid (Abbott, St Paul, MN) and the
Optrell (Biosense Webster, Irvine, CA), facilitate high-density mapping and assessment
of real-time wavefront propagation. Here, we present a first report of entanglement
of an Optrell catheter with an Impella CP (Abiomed, Danvers, MA), suggesting alternative
strategies should be taken in patients requiring mechanical support during VT ablation
when using grid mapping catheters.
Key Teaching Points
•
The Optrell catheter (Biosense Webster, Irvine, CA) is a novel grid catheter developed
for the mapping of atrial and ventricular arrhythmias, which includes 48 microelectrodes
distributed over 6 splines to facilitate high-density mapping and real-time assessment
of propagation vectors.
•
Use of the Optrell mapping catheter presents a hazard in patients requiring Impella-based
mechanical circulatory support (MCS), given risk of entanglement of the mapping catheter
with the Impella pigtail.
•
In patients requiring Impella-based MCS for ventricular tachycardia ablation, an alternative
high-density mapping catheter (Octaray; Biosense Webster, Irvine, CA) or non-pigtail
Impella (Impella 5.5; Abiomed, Irvine, CA) should be used.
Case report
A 50-year-old male patient with no significant past medical history presented to the
hospital with new heart failure with reduced ejection fraction. Transthoracic echocardiogram
demonstrated global hypokinesis, LV cavity dilatation, apical aneurysm, and LV ejection
fraction of 10%. Coronary angiography demonstrated multivessel coronary artery disease,
after which he was deemed not a candidate for coronary artery bypass surgery owing
to diffuse coronary disease with poor revascularization targets. Cardiac magnetic
resonance imaging showed focal, partial-thickness LV subendocardial late gadolinium
enhancement in multiple territories, consistent with prior myocardial infarction (Figure 1A).
During the hospitalization, he had frequent premature ventricular contractions with
right bundle, left superior axis as well as runs of polymorphic VT. He underwent placement
of a single-chamber implantable cardiac defibrillator and was started on goal-directed
medical therapy for heart failure.
Figure 1
A: Induction of clinical ventricular tachycardia (VT) with right bundle, right superior
axis, which was localized to the anterior and inferior septum. B: Cardiac magnetic
resonance imaging demonstrates severe global left ventricular systolic dysfunction
with focal partial-thickness subendocardial late gadolinium enhancement in the anterior,
anteroseptal, and anterolateral waves, corresponding to region where critical isthmus
was mapping in VT, along with fractioned potentials and deceleration zone with right
ventricular pacing wavefront.
After discharge, he had multiple episodes of monomorphic VT, which terminated with
antitachycardia pacing. He was started on amiodarone, but developed VT storm treated
with multiple shocks from his implantable cardiac defibrillator. He was started on
a lidocaine drip and admitted to the cardiac intensive care unit. Given incessant
VT, he was intubated, sedated, and underwent stellate ganglion block in preparation
for VT ablation. PAINESD score was 18, suggesting high risk for acute hemodynamic
decompensation.
5
Plans were made in consultation with interventional cardiology and the advanced heart
failure team for temporary MCS during VT ablation. Based on right-heart catheterization
with preserved cardiac output and right ventricular function (right atrium 6 mmHg,
right ventricle 30/8 mmHg, pulmonary artery 30/12 mmHg, pulmonary capillary wedge
12 mmHg, cardiac output [Fick] 5.17 L/min, cardiac index 2.7 L/min/m2), an Impella
CP (Abiomed, Danvers, MA) was selected for MCS during the case. The Impella CP can
provide up to 4.3 L/min of support via percutaneous axillary or femoral access (Figure 2D).
Figure 2
A: Fluoroscopy showing entanglement of the Optrell mapping catheter (Biosense Webster,
Irvine, CA) and Impella CP (Abiomed, Danvers, MA). The catheter was carefully disentangled
under fluoroscopic guidance. B: Recreation of catheter entanglement outside the body.
C: Impella CP (top) along with Optrell mapping catheter (bottom). D: The Impella 5.5
(top) can provide up to 5.5 L of mechanical support through axillary cutdown access
and does not use a pigtail, compared to the Impella CP (bottom). The Impella CP pigtail
poses a risk for entanglement with the Optrell mapping catheter.
On the day of the procedure, the patient was brought to the electrophysiology laboratory.
General anesthesia was administrated by a cardiac anesthesiologist with a radial arterial
line for continuous blood pressure monitoring. An Impella CP was placed via the left
femoral artery. The device was positioned across the aortic valve annulus, with approximately
3.5 cm from the annulus to mid-inlet, and an additional 5.5 cm from mid-inlet to tip
of the pigtail catheter.
9
Transseptal puncture was performed and the LV endocardium was mapped using the Optrell
grid catheter and electroanatomic mapping system (CARTO 3, Version 7; Biosense Webster,
Irvine, CA).
10
Given the patient’s tenuous clinical status, a substrate-based ablation approach using
isochronal latest activation mapping was planned. While mapping the LV endocardium,
the Optrell catheter became difficult to manipulate and was noted to have been entangled
in the Impella CP pigtail (Figure 2A and 2B). After several attempts at careful manipulation
of the Optrell catheter while holding the Impella fixed, the Optrell catheter was
freed from the pigtail and removed from the body without complication (Supplemental
Video 1).
The remainder of the LV endocardium was then mapped using an Octaray mapping catheter
(Biosense Webster, Irvine, CA) without incident. There was diffusely abnormal bipolar
voltage with local abnormal ventricular activity and late potentials along the anterior
septum and inferior septum with multiple potential deceleration zones. Given multiple
potential conduction channels, the clinical VT (right bundle, right superior axis
with cycle length 425 ms) (Figure 1B) was induced, mapped, and successfully ablated.
Additional areas were targeted for ablation guided by isochronal latest activation
mapping. The patient was noninducible at the end of the procedure.
Discussion
This is the first reported case of entanglement of Impella and Optrell mapping catheters
during VT ablation. Although the mapping catheter was extracted after careful manipulation,
this case demonstrates the hazards of using this catheter (and likely other grid-based
mapping catheters) with a pigtail-based Impella. A number of studies have shown benefit
in supporting patients at high risk for hemodynamic decompensation with MCS during
VT ablation.
1
,
6
,
7
,
11
,
12
The Impella CP is frequently used given ease of placement from the femoral artery
and up to 4.3 L/min of support. Other options for percutaneous support include the
TandemHeart (Cardiac Assist, Inc, Pittsburg, PA), which is inserted through a 21F
venous cannula placed transseptally in the left atrium with 17F arterial return cannula
as well as VA ECMO. Use of the TandemHeart carries higher risk of vascular complication
than the Impella and requires a retrograde approach for mapping and ablation.
13
Although VA ECMO can provide complete circulatory support, it has a higher risk of
vascular complications, it can increase LV afterload, thereby worsening LV function,
and is resource intensive.
1
The Impella CP is placed across the aortic valve annulus as described above and includes
a pigtail catheter that sits in the LV.
9
There is risk of a grid-based mapping catheter becoming entangled with the Impella
pigtail, given the spacing of the splines in the paddle design. Notably, there are
no reports of similar issues with the similarly designed Advisor HD Grid (Abbott,
Abbott Park, IL) mapping catheter, although there are reports of entanglement of this
catheter with other diagnostic catheters.
14
The risk of entanglement with the Impella can be avoided by using the Impella 5.5
(Abiomed, Danvers, MA) (Figure 2D), which does not have a pigtail. The Impella 5.5
can provide an additional support over the Impella CP (up to 5.5 L/min), but requires
a surgical axillary artery cutdown or transcaval approach.
9
Mapping catheters that are not grid/paddle based (such as the Octaray or PentaRay),
or a linear ablation catheter, can be used with the Impella CP without risk of entanglement.
In cases where entanglement between a grid catheter and the Impella CP pigtail does
occur, holding the Impella stable and then rotating the catheter while adjusting the
flex can free the catheters.
Conclusion
This is the first reported case of Impella CP and Optrell mapping catheter entanglement
during VT ablation with MCS. When an Impella CP is used, non-grid-based mapping catheters
should be used. If MCS is needed and the electrophysiologist has reasons to use a
grid-based mapping catheter such as the Optrell or HD Grid, MCS without a pigtail
catheter such as the Impella 5.5, TandemHeart, or ECMO avoids the risk of entanglement,
but may increase hospital length of stay and vascular access risk.