Intraoperative amiodarone as prophylaxis against atrial fibrillation after coronary operations

Background. New onset of atrial fibrillation is a frequent complication after coronary artery bypass grafting and is a major cause of postoperative morbidity. Preoperative oral treatment with amiodarone hydrochloride has been shown to be efficacious as prophylaxis. The present study investigated whether intraoperative use of intravenous amiodarone has a preventive effect on 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 different 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 on-line monitoring was performed for 10 days. Arrhythmias were analyzed with respect to type, frequency, duration, and clinical relevance. Results. New onset of atrial fibrillation occurred in 24% of patients in group 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, 24%; group III, 32%; p< 0.05, group I versus group III) and appeared significantly 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). Temporary atrial pacing because of bradycardia (<60 beats per minute) was necessary significantly more often in group I (group I, 48%; group II, 40%; group III, 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 (group I, 14%; group II, 20%; group III, 14%), and duration of hospital stay (group I, 14.0 days; group II, 14.4 days; group III, 14.7 days) were not different between groups. Conclusions. Intraoperative prophylactic use of amiodarone does not prevent new onset of atrial fibrillation in patients undergoing coronary artery bypass grafting and had no effect on outcome. Therefore, intraoperative prophylactic treatment with amiodarone at the tested doses does not appear to be justified.