Oral amiodarone for prevention of atrial fibrillation after open heart surgery, the Atrial Fibrillation Suppression Trial (AFIST): a randomised placebo-controlled trial

Background β-blockers and amiodarone reduce the frequency of atrial fibrillation after open-heart surgery but the effectiveness of oral amiodarone in older patients already receiving β-blockers is unknown. We have assessed the efficacy of oral amiodarone in preventing atrial fibrillation in patients aged 60 years or older undergoing open-heart surgery. Methods We did a randomised, double-blind placebocontrolled trial in which patients undergoing open-heart surgery (n=220, average age 73 years) received amiodarone (n=120) or placebo (n=100). Patients enrolled less than 5 days before surgery received 6 g of amiodarone or placebo over 6 days beginning on preoperative day 1. Patients enrolled at least 5 days before surgery received 7 g over 10 days beginning on preoperative day 5. Findings Patients on amiodarone had a lower frequency of any atrial fibrillation (22·5% vs 38·0%; p=0·01; absolute difference 15·5% [95% CI 3·4–27·6%]), and there were significant differences in favour of the active drug for symptomatic atrial fibrillation (4·2% vs 18·0%, p=0·001), cerebrovascular accident (1·7% vs 7·0%, p=0·04), and postoperative ventricular tachycardia (1·7% vs 7·0%, p=0·04). β-blocker use (87·5% amiodarone vs 91·0% placebo), nausea (26·7% vs 16·0%), 30-day mortality (3·3% vs 4·0%), symptomatic bradycardia (7·5% vs 7·0%), and hypotension (14·2% vs 10·0%) were similar. Interpretation Oral amiodarone prophylaxis in combination with β-blockers prevents atrial fibrillation and symptomatic fibrillation and reduces the risk of cerebrovascular accidents and ventricular tachycardia.