Background: The purpose of this study was to evaluate the safety and efficacy of amiodarone in the treatment of newonset atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery.

Methods: The study included 20 patients (15 males, 5 females; mean age 64±9 years; range 43 to 79 years) who underwent CABG surgery for ischemic heart disease and received amiodarone treatment for AF that developed in the early postoperative period. Amiodarone was administered with an initial infusion of 150 mg/10 min, followed by infusions of 1 mg/ min (first 0-6 hours) and 0.5 mg/min (6-24 hours). Following completion of 1,000-1,200 mg intravenous infusions, oral administration was continued with 400 mg (2x200 mg).

Results: The mean time to AF development was 21.0±23.2 hours; the onset of AF was within the first eight hours in 10 patients, and between 13 to 70 hours in the remaining patients. Eight patients (40%) converted to sinus rhythm with amiodarone treatment within a mean of 25.4±22.0 hours, while 12 patients (60%) had persistent AF. Of these, three patients (15%) underwent electrical cardioversion on the seventh day of amiodarone treatment, and three patients were discharged with AF. Mortality occurred in seven patients (35%), of whom six had persistent AF. Following the development of AF, seven patients (35%) required inotropic support, and two patients (10%) required intraaortic balloon pump insertion. Bradycardia was seen in four patients (20%) following initiation of amiodarone. Patients with persistent AF showed significantly high rates of postoperative support (p<0.05) and, albeit not significant, higher rates of bradycardia (p=0.06) and mortality (p=0.08), and longer intubation time, intensive care unit stay, and hospital stay.

Conclusion: Our findings showed that amiodarone was not effective in the treatment of new-onset AF following CABG surgery and unresponsive AF was associated with increased inotropic support and mortality.

Keywords : Amiodarone/therapeutic use/adverse effects; anti-arrhythmia agents; atrial fibrillation/prevention & control; cardiopulmonary bypass; postoperative complications