Increased Epicardial Adipose Tissue Volume Correlates With Cardiac Sympathetic Denervation in Patients With Heart Failure

RATIONALE:: It has been reported that epicardial adipose tissue (EAT) may affect myocardial autonomic function. OBJECTIVE:: The aim of this study was to explore the relationship between EAT and cardiac sympathetic nerve activity in heart failure (HF) patients. METHODS AND RESULTS:: In 110 patients with systolic HF, we evaluated the correlation between echocardiographic EAT thickness and cardiac adrenergic nerve activity assessed by I-metaiodobenzylguanidine (I-MIBG). The predictive value of EAT thickness on cardiac sympathetic denervation [I-MIBG early and late heart to mediastinum ratio (H/M) and SPECT total defect score (TDS)] was tested in a multivariate analysis. Furthermore, catecholamine levels, catecholamine biosynthetic enzymes and sympathetic nerve fibers were measured in EAT and subcutaneous adipose tissue (SCAT) biopsies obtained from HF patients who underwent cardiac surgery. EAT thickness correlated with I-MIBG early and late H/M and SPECT TDS, but not with left ventricular ejection fraction (LVEF). Moreover, EAT resulted as an independent predictor of I-MIBG early and late H/M and SPECT TDS, and showed a significant additive predictive value on I-MIBG planar and SPECT results over demographic and clinical data. Although no differences were found in sympathetic innervation between EAT and SCAT, EAT showed an enhanced adrenergic activity demonstrated by the increased catecholamine levels and expression of catecholamine biosynthetic enzymes. CONCLUSIONS:: This study provides the first evidence of a direct correlation between increased EAT thickness and cardiac sympathetic denervation in HF.