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 (