Purpose: Epicardial adipose tissue (EAT) is associated with atrial fibrillation. We investigated the effect of EAT on postoperative atrial fibrillation (POAF) after cardiac surgery.

Methods: In all, 77 patients underwent scheduled cardiac surgery. Before the operation, we measured total epicardial adipose tissue (Total EAT) and left atrial (LA) EAT by three-dimensional computed tomography (CT). During surgery, we obtained samples of the right atrial appendage, aortic fat, and epicardial fat. The primary endpoint was occurrence of POAF within 1 week after surgery.

Results: POAF occurred in 21 patients (27%). Assessment of preoperative characteristics revealed significant differences of age and the use of aldosterone blockers and loop diuretics between the patients with and without POAF. In univariate analysis, the LA EAT/Total EAT ratio, age, use of aldosterone blockers and loop diuretics, P wave duration, cardioplegia volume, and central venous pressure (CVP) were all higher in POAF group. However, logistic regression analysis with propensity score matching found no significant differences of these factors although the LA EAT/Total EAT ratio was higher in POAF group.

Conclusion: The use of loop diuretics showed the strongest association with POAF. Logistic regression analysis suggested that a high LA EAT/Total EAT ratio had the second strongest association with POAF.