We sought to ascertain whether myocardial scarring occurs in living unselected patients
with hypertrophic cardiomyopathy (HCM).
Myocardial scarring is known to occur in select HCM patients, who were highly symptomatic
prior to death or who died suddenly. The majority of HCM patients, however, are minimally
symptomatic and have not suffered sudden death.
Cine and gadolinium-enhanced magnetic resonance imaging was performed in 21 HCM patients
who were predominantly asymptomatic. Gadolinium hyperenhancement was assumed to represent
myocardial scar, and the extent of scar was compared to left ventricular (LV) morphology
and function.
Scarring was present in 17 patients (81%). Scarring occurred only in hypertrophied
regions (> or =10 mm), was patchy with multiple foci, and predominantly involved the
middle third of the ventricular wall. All 17 patients had scarring at the junction
of the interventricular septum and the right ventricular (RV) free wall. On a regional
basis, the extent of scarring correlated positively with wall thickness (r = 0.36,
p < 0.0001), and inversely with wall thickening (r = -0.21, p < 0.0001). On a per
patient basis, the extent of scarring (mean, 8 +/- 9% of LV mass) was minimally related
to maximum wall thickness (r = 0.40, p = 0.07) and LV mass (r = 0.33, p = 0.15), and
correlated inversely with ejection fraction (r = -0.46, p = 0.04).
Myocardial scarring is common in asymptomatic or mildly symptomatic HCM patients who
have not suffered sudden death. When present, scarring occurs in hypertrophied regions,
is consistently localized to the junctions of the septum and RV free wall, and correlates
positively with regional hypertrophy and inversely with regional contraction.