An increase in epicardial adipose tissue (EAT) volume is associated with the development of atrial fibrillation (AF) and coronary artery disease (CAD), but little is known about differences in its distribution.

We included 50 patients with paroxysmal AF (PAF), 50 patients with CAD, and 50 control patients. Using multidetector computed tomography, EAT volumes surrounding the whole heart (total EAT), the atrium (atrial-EAT), and the ventricle (ventricular-EAT) were measured. EAT atrial/ventricular (A/V) ratio was calculated by dividing atrial- by ventricular-EAT volume. The total EAT volume indexes in the PAF and CAD groups were significantly larger than those in the control group. The atrial-EAT volume index in the PAF group was significantly larger than that in the CAD and control groups, whereas the ventricular-EAT volume index in the CAD group was significantly larger than that in the PAF and control groups. Thus, EAT A/V ratio was smaller in the CAD and control group than that in the PAF group (0.28 ± 0.12 vs. 0.38 ± 0.13 vs. 0.54 ± 0.33, P < .001). Univariate and multivariate linear regression analysis showed EAT A/V ratio to be independently associated with cardiovascular disease type (PAF vs. CAD; P < .001, β = .463).

Atrial- and ventricular-dominant distribution of EAT was observed in the PAF and CAD groups, respectively. Uneven distribution of EAT may imply the direct contribution of EAT-related inflammation to the pathogenesis of AF or CAD.