Epicardial adipose tissue is associated with impaired outcomes in genotype-positive hypertrophic cardiomyopathy.

BACKGROUND AND AIMS: Hypertrophic cardiomyopathy (HCM) is characterized by increased risk of malignant ventricular arrhythmias (MVA) and heart failure (HF). There is increasing awareness that epicardial adipose tissue (EAT) is associated with an adverse prognosis in cardiovascular disease, but its role in genotype-positive HCM patients is unknown.

METHODS

EAT volume was quantified by cardiovascular magnetic resonance in a retrospective genotype-positive HCM cohort. Patients were split into high and low EAT groups by the median. Multivariable Cox regression was used to examine the association between EAT volume and (1) MVA (sustained ventricular tachycardia, ventricular fibrillation, appropriate implantable cardioverter defibrillator shock, sudden cardiac death (SCD), or death of unknown cause), and (2) HF events (HF hospitalization, heart transplantation, or HF-related mortality).

RESULTS

We included 282 patients (48±14 years, 64.5% male). The high EAT group had greater maximal wall thickness (25.0±6.4 vs 20.8±4.9mm, p<0.001), more extensive late gadolinium enhancement (6.1% [0.0-14.0] vs 1.0% [0.0-6.2], p<0.001), and more frequent left ventricular outflow tract obstruction (42.6% vs 15.6%, p<0.001) compared with the low EAT group. During 62 [32-96] months of follow-up, EAT volume was independently associated with the incidence of MVA (HR 1.04 [95%CI 1.02-1.06], p<0.001) and HF events (HR 1.05 [95%CI 1.03-1.08], p<0.001). EAT volume showed good discriminative ability for both MVA (C-statistic 0.79, p<0.001) and HF events (C-statistic 0.79, p<0.001), and appeared to perform better than the HCM SCD risk score for MVA (C-statistic comparison p=0.011).

CONCLUSION

EAT accumulation is associated with phenotype severity and independently associated with the incidence of MVA and HF events in genotype-positive HCM patients.These findings suggest that EAT should be considered a novel factor in HCM risk assessment.