Abstract
BACKGROUND: Risk stratification for sudden cardiac death (SCD) in patients with nonischemic cardiomyopathy (NICM) remains challenging. OBJECTIVES: This study aimed to investigate the impact of epicardial adipose tissue (EAT) on SCD in NICM patients. METHODS: Our study cohort included 173 consecutive patients (age 53 ± 14 years, 73% men) scheduled for primary prevention implantable cardioverter-defibrillators (ICDs) implantation who underwent preimplant cardiovascular magnetic resonance. EAT volume surrounding both ventricles was manually quantified from cine left ventricular short-axis images by summation of the EAT volume of each slice using the modified Simpson rule. The primary endpoint was appropriate ICD therapy. RESULTS: During the mean follow-up of 3.6 years, 24 patients (14%) experienced an endpoint. An inverse and proportional relationship was evident between EAT and subsequent ICD therapies (P = 0.004). Even after adjusting for left ventricular mass and ejection fraction, EAT was significantly lower in patients with ICD therapy than those without. Low EAT was independently associated with an increased risk of ICD therapy in NICM patients (HR(ad) per 10 mL/m(2) decrease, 1.65; 95% CI: 1.17-2.42; P = 0.007). EAT ≤50 mL/m(2) demonstrated a 3-fold increase in SCD event risk, with an estimated likelihood of 57% at 5 years. When considered with other potential risk factors, EAT provided incremental prognostic value in predicting ICD therapy. CONCLUSIONS: Low ventricular EAT was associated with increased SCD risk in NICM patients receiving primary prevention ICD implantation, even in the presence of other risk markers. These data suggest a potential clinical role of EAT in selecting NICM patients who would benefit most from ICD implantation.