Effect of Amiodarone on atrial fibrillation after coronary artery bypass surgery

OBJECTIVE: Atrial fibrillation occurs in 10%–40% of patients undergoing coronary artery bypass grafting. This study investigates whether prophylactic Amiodarone use reduces the rate of atrial fibrillation post myocardial revascularisation.

METHODS: In a prospective study conducted at the Cardiothoracic Center over a 6 month period, 192 patients were randomized to either Amiodarone or placebo. The Amiodarone group received Amiodarone infusion followed by oral Amiodarone on a decreasing dose for a total period of 6 weeks. The placebo group were started on an infusion of dextrose 5% solution and then maintained on a matched regimen of placebo tablets for a corresponding period of time.

RESULTS: Of the 100 patients recruited for the Amiodarone arm of the study, 12 were excluded for a variety of reasons detailed in the discussion with atrial fibrillation occurring in 28 (a rate of 32%). Of the 92 controls, 32 developed atrial fibrillation (a rate of 35%). There were no significant differences between the groups. The maximum ventricular rate during atrial fibrillation however, was significantly slower in the Amiodarone group (108±18) compared to (136±22) P<0.05. Moreover, there were no significant differences in the mortality rates between the 2 groups; a rate of 3% (3 of 88) in the Amiodarone group as opposed to 3% (3 of 92) in the controls.

CONCLUSION: In this study prophylactic Amiodarone did not reduce the rate of atrial fibrillation post coronary artery bypass surgery. However, it reduced the maximum ventricular rate. Amiodarone had no effect on mortality post coronary artery bypass.