Simple Amiodarone Protocol Reduces Postoperative Atrial Fibrillation

BACKGROUND: : Incorporating amiodarone into an existing postoperative atrial fibrillation (AF) prevention pathway may reduce postoperative AF and length of stay (LOS). METHODS: : From July 2002 through December 2002, 476 consecutive cardiac surgical patients were managed with an AF prevention protocol using aggressive potassium replacement, intraoperative/postoperative magnesium supplementation, and postoperative resumption of β-blockers. From January 2003 through June 2003, 592 additional patients were subjected to the same protocol except amiodarone was initiated intraoperatively (150 mg intravenously) and continued postoperatively until discharge (200 mg orally three times daily). Incidence of AF, postoperative LOS, and AF risk factors were collected prospectively and compared using regression models with propensity scores to adjust for dissimilarities between groups. RESULTS: : Incorporating amiodarone into an existing AF protocol resulted in a 45% reduction in postoperative AF (29% [136/476] versus 16% [94/592], P < 0.0001). After adjustment for covariates and propensity score, the relative risk reduction with amiodarone in this protocol remained significant (P = 0.001, RR 0.65, 95% CI 0.5-0.8). Multivariate risks for postoperative AF included no amiodarone (P = 0.0001), age (P < 0.0001), ejection fraction <40% (P = 0.0005), ventilator support >24 hours (P = 0.002), no postoperative β-blocker (P = 0.002), and mitral valve procedure (P = 0.03). When postoperative AF did occur, risk adjusted LOS was less in patients on the amiodarone protocol (mean 9.4 days versus 13.1 days, P = 0.06). Readmission after discharge for any reason (10% [49/476] versus 8% [45/592], P = 0.1) or for AF (1.1% [5/476] versus 0.7% [4/592], P = 0.5) was similar between groups. CONCLUSION: : Amiodarone initiated intraoperatively followed by oral dosing significantly reduces postoperative AF and tends to reduce LOS if AF occurs.