A comparison between oral antiarrhythmic drugs in the prevention of atrial fibrillation after cardiac surgery: the pilot study of prevention of postoperative atrial fibrillation (SPPAF), a randomized, placebo-controlled trial

Background Atrial fibrillation (AF) frequently occurs after cardiac surgical procedures, and β-blockers, sotalol, and amiodarone may reduce the frequency of AF after open heart surgery. This pilot trial was designed to test whether each of the active oral drug regimens is superior to placebo for prevention of postoperative AF and whether there are differences in favor of 1 of the preventive strategies. Methods and results We conducted a randomized, double-blinded, placebo-controlled trial in which patients undergoing cardiac surgery in the absence of heart failure and without significant left ventricular dysfunction (n = 253; average age, 65 ± 11 years) received oral amiodarone plus metoprolol (n = 63), metoprolol alone (n = 62), sotalol (n = 63), or placebo (n = 65). Patients receiving combination therapy (amiodarone plus metoprolol) and those receiving sotalol had a significantly lower frequency of AF (30.2% and 31.7%; absolute difference, 23.6% and 22.1%; odds ratios [OR], 0.37 [95% CI, 0.18 to 0.77, P < .01 vs placebo] and 0.40 [0.19 to 0.82, P = .01 vs placebo]) compared with patients receiving placebo (53.8%). Treatment with metoprolol was associated with a 13.5% absolute reduction of AF (P = .16; OR, 0.58 [0.29 to 1.17]. Treatment effects did not differ significantly between active drug groups. Adverse events including cerebrovascular accident, postoperative ventricular tachycardia, nausea, and dyspepsia, in hospital death, postoperative infections, and hypotension, were similar among the groups. Bradycardia necessitating dose reduction or drug withdrawal occurred in 3.1% (placebo), 3.2% (combined amiodarone and metoprolol; P = .65 vs placebo), 12.7% (sotalol; P < .05 vs placebo), and 16.1% (metoprolol; P < .05 vs placebo). Patients in the placebo group had a nonsignificantly longer length of hospital stay as compared with the active treatment groups (13.1 ± 8.9 days vs 11.3 ± 7; P = .10), with no significant difference between the active treatment groups. Conclusions Oral active prophylaxis with either sotalol or amiodarone plus metoprolol may reduce the rate of AF after cardiac surgery in a population at high risk for postoperative AF. Treatment with metoprolol alone resulted in a trend to a lower risk for postoperative AF.