EFFECT OF AMIODARONE ON RATES OF POST-OPERATIVE ATRIAL FIBRILLATION IN PATIENTS UNDERGOING CARDIAC SURGERY

Abstract

Despite advancements in medical therapy, post-operative atrial fibrillation (POAF) remains a common complication following cardiac surgery and is associated with increased morbidity and mortality. The purpose of this study was to determine whether routine administration of amiodarone reduced the incidence of POAF in patients undergoing cardiac surgery. All patients undergoing non-emergent, on-pump isolated coronary artery bypass grafting (CABG), isolated valve, or concomitant CABG/valve surgery performed by a single surgeon from January 2010 through September 2013 were identified. Patients with pre-existing atrial fibrillation were excluded. Of the 558 patients who formed the final study population, 321 patients (57.5%) received the standard of care in terms of anti-arrhythmic and heart rate-controlling therapies. The remaining 237 (42.4%) received, in addition to the standard of care, routine amiodarone therapy which included a 300 mg intravenous bolus of amiodarone immediately upon return from the operating room followed by 400 mg orally three times daily for a total of 5 days or up until the date of discharge depending on which came first. Baseline characteristics, intra-operative variables and rates of in-hospital post-operative adverse events were compared between the two groups. Multiple logistic regression modeling was used to determine the risk-adjusted effect of amiodarone use on rates of POAF. Patients who received amiodarone were more likely to have a body mass index ≥ 30 kg/m2 (p = 0.02), to have NYHA IV symptoms (p = 0.01), and to leave the operating room on inotropic support (p = 0.04). While rates of in-hospital post-operative adverse events were generally similar between the two groups, amiodarone therapy was associated with lower rates of atrial fibrillation (Table 1). Following adjustment for potential confounding variables, amiodarone emerged as an independent predictor of reduced rates of POAF (OR 0.59, 95% CI 0.40-0.87, p < 0.01). Patients who received amiodarone therapy possessed an increased burden of co-morbid disease upon presentation for surgery and a higher rate of inotropic support immediately following surgery. Despite this, amiodarone was found to be associated with significantly reduced rates of POAF. The results of this study support the routine use of amiodarone in patients undergoing cardiac surgery.