Impact of Epicardial Anterior Fat Pad Retention on Postcardiothoracic Surgery Atrial Fibrillation Incidence : The AFIST-III Study

ObjectivesWe conducted a randomized, blinded, controlled study evaluating the impact of anterior fat pad (AFP) maintenance on postoperative atrial fibrillation (POAF) incidence.BackgroundDrugs with antiadrenergic effects reduce POAF. Because the epicardial AFP is parasympathetically innervated, its routine excision during coronary artery bypass grafting (CABG) might precipitate autonomic imbalance and induce POAF.MethodsPatients (n = 180, mean age = 66 ± 10 years, 80% men, 5% with previous atrial fibrillation) undergoing CABG surgery were randomized to either AFP maintenance or AFP removal. Routine prophylaxis against POAF with beta-blockers (85%) and amiodarone (28%) was allowed on the basis of caregivers’ discretion. The development of POAF, total hospital costs, and heart rate variability was compared between groups.ResultsAnterior fat pad maintenance did not reduce POAF incidence (34.8% vs. 35.2%, p = 0.950) or total hospital costs (data as medians with 25%, 75% percentiles: $22,940 [$17,629, $29,274] vs. $23,866 [$18,602, $30,370], p = 0.647) but was associated with higher heart rate variability (SD of normal-to-normal RR intervals [SDNN]: 31.7 ± 24.6 vs. 22.7 ± 8.3, p = 0.05 and SD of all 5-min mean RR intervals [SDANN 5]: 17.1 ± 11.9 vs. 10.1 ± 5.5, p = 0.003) than AFP removal.ConclusionsMaintaining the AFP prevents attenuation of parasympathetic tone after CABG but does not reduce POAF or total hospital costs in any appreciable way.