Optimal β-blocker for prevention of atrial fibrillation after on-pump coronary artery bypass graft surgery: Carvedilol versus metoprolol

Background: Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass graft (CABG) surgery. It has been shown that prophylactic oral β-blocker administration reduces the incidence of post-CABG AF. However, the optimal β-blocker has not been identified. Objective: This study sought to determine whether oral carvedilol (with its unique anti-inflammatory and antioxidant properties) is more effective than oral metoprolol for prevention of AF after CABG surgery. Methods: Between April 2006 and December 2006, 120 patients (63 men, mean age 61 ± 9.4 years) who were scheduled to undergo their first on-pump CABG were enrolled in this study. The patients were randomized in a prospective 1:1 manner to receive either oral carvedilol (n = 60) or oral metoprolol (n = 60). The end point of the study was the occurrence of the new-onset AF during the first 5 days aftere CABG. Results: AF occurred in 29 of 120 patients (24.0). The incidence of postoperative AF was 15.0 (9 of 60) in the carvedilol group and 33 (20 of 60) in the metoprolol group (P = .022). The carvedilol group was treated with mean daily dose of 46 ± 9 mg and metoprolol group with mean daily dose of 93 ± 11 mg. There were no differences between the study groups regarding any known preoperative, perioperative, or postoperative characteristics (all values were P >.05). No significant adverse effect was observed in either group. Conclusion: This prospective study suggested that oral carvedilol is more effective than oral metoprolol in the prevention of AF after on-pump CABG. It is well tolerated when started before and continued after the surgery. However, further prospective studies are needed to clarify this issue. © 2007 Heart Rhythm Society