Prevention of atrial fibrillation after cardiac surgery: the significance of postoperative oral amiodarone.

Study Objectives: Atrial fibrillation (AF) is a common occurrence after cardiac surgery (10 to 53%) that contributes to increased length of stay and hospital cost. Recent evidence suggests that treatment with amiodarone may provide safe and effective prophylaxis against AF in many patients undergoing cardiac operations. This study sought to investigate whether oral amiodarone administered postoperatively would reduce the incidence of postoperative AF.

Design: Prospective nonrandomized cohort study.

Patients And Participants: In this prospective study, 1,196 consecutive patients who underwent various open-heart procedures with cardiopulmonary bypass between July 1999 and February 2000 received oral amiodarone, 400 mg bid, from the transfer to the cardiovascular recovery room until the day of hospital discharge, or up to 7 days postoperatively. The incidence of AF in this group of patients was compared with a group of 1,246 patients who underwent cardiac surgery with cardiopulmonary bypass in the preceding 8-month period (November 1998 to June 1999) at the same institution without receiving amiodarone postoperatively.

Setting: Tertiary health-care center.

Measurement And Results: AF developed in 294 patients (25%) in amiodarone-treated group and in 385 patients (31%) in the control group (p = 0.001). In multivariate logistic regression analysis, oral amiodarone treatment emerged as an independent predictor of lower risk of AF (odds ratio, 0.7; 95%; 95% confidence interval, 0.6 to 0.9; p = 0.002) and shorter hospital length of stay (odds ratio, 0.8; 95% confidence interval, 0.5 to 0.9; p = 0.006).

Conclusions: Postoperative oral amiodarone treatment is a safe and effective regimen associated with a reduced incidence of new-onset AF and decreased length of hospital stay. Prospective randomized trials are needed to evaluate the benefits of amiodarone treatment relative to its side effect profiles.