Intraoperative amiodarone as prophylaxis against atrial fibrillation aftercoronary operations

Background. New onset of atrial fibrillation is a frequent complication aft er coronary artery bypass grafting and is a major cause of postoperative mo rbidity. Preoperative oral treatment with amiodarone hydrochloride has been shown to be efficacious as prophylaxis. The present study investigated whe ther intraoperative use of intravenous amiodarone has a preventive effect o n the incidence of atrial fibrillation after coronary revascularization. Methods. In a prospective study, 150 consecutive patients (mean age, 63 +/- 8 years; 132 men and 18 women) undergoing coronary artery bypass grafting were randomly assigned to one of three groups. Two groups received differen t doses of intravenous amiodarone (group I, 300-mg bolus and 20 mg . kg(-1) . day(-1) for 3 days; group II, 150-mg bolus and 10 mg . kg(-1) . day(-1) for 3 days) after aortic cross-clamping and one group, placebo (group III). Continuous electrocardiographic online monitoring was performed for 10 day s. Arrhythmias were analyzed with respect to type, frequency, duration, and clinical relevance. Results. New onset of atrial fibrillation occurred in 24% of patients in gr oup I, 28% in group II, and 34% in group III (p = not significant). Atrial fibrillation with a rapid ventricular response (>120 beats per minute) was significantly more frequent in the control group (group I, 14%; group II, 2 4%; group III, 32%; p < 0.05, group I versus group III) and appeared signif icantly earlier (group I, day 4.3 +/- 2.5; group II, day 4.8 +/- 2.9; group III, day 2.6 +/- 1.3; p < 0.05, group III versus groups I and II). Tempora ry atrial pacing because of bradycardia (<60 beats per minute) was necessar y significantly more often in group I(group I, 48%; group II, 40%; group II I, 28%; p < 0.05, group I versus group III). Early mortality rate (group I, 4%; group II, 2%; group III, 4%), rate of perioperative complications (gro up I, 14%; group II, 20%; group III, 14%), and duration of hospital stay (g roup I, 14.0 days; group II, 14.4 days; group III, 14.7 days) were not diff erent between groups. Conclusions. Intraoperative prophylactic use of amiodarone does not prevent new onset of atrial fibrillation in patients undergoing coronary artery by pass grafting and had no effect on outcome. Therefore, intraoperative proph ylactic treatment with amiodarone at the tested doses does not appear to be justified. (C) 2000 by The Society of Thoracic Surgeons.