Retaining the aortic fat pad during cardiac surgery decreases postoperative atrial fibrillation

Background: Atrial arrhythmias are a common and serious complication of car diac surgical procedures. Reports describing pericardiac neurogenic tissue led us to hypothesize that removal of the aortic fat pad could cause an aut onomic imbalance and contribute to atrial arrhythmias following cardiac sur gery. Methods: Patients (n = 131) underwent either conventional cardiopulmonary b ypass surgery (CPB) or off-pump coronary artery bypass (OPCAB) surgery. The aortic fat pad was either left intact or removed. The incidence of de novo atrial arrhythmias during the patient's hospital stay was tabulated. Patie nts with peri-operative myocardial infarction or pre-existing atrial or sup raventricular arrhythmias were excluded. Results: Demographics, preoperative medications, ASA and NYHA classificatio ns, and complication rates (other than for atrial arrhythmias) did not diff er among the groups. The STS-predicted mortality was higher in the CPB/Fat- Pad-Removed group (2.23 +/- 1.89) than in either the OPCAB/Fat-Pad-Intact ( 1.09 +/- 0.80) or OPCAB/Fat-Pad-Removed (1.02 +/- 0.62) groups (p < 0.05). Atrial arrhythmias were present in 19 of 131 patients (14.5%). Logistic reg ression demonstrated a significantly elevated atrial arrhythmia rate when t he fat pad was removed (odds ratio = 3.49, 95% bounds 1.09 to 11.18, p = 0. 035). Neither the pump status nor the cross product of pump status by fat p ad status were significant in this pilot study. Conclusions: Retaining the aortic fat pad during coronary artery bypass sur gery is correlated with a decreased incidence of postoperative atrial arrhy thmias.