Esmolol versus diltiazem in atrial fibrillation following coronary artery bypass graft surgery

Purpose: Atrial fibrillation (AF) is the most common arrhythmic complication following coronary artery bypass graft surgery (CABG). The efficacy and safety of esmolol and diltiazem were compared in patients with post-CABG AF. Methods: This study was a retrospective medical record review of consecutive patients with post-CABG AF ≥15 min in duration with a ventricular rate ≥110 b.p.m. who received either i.v. esmolol (n = 59) or i.v. diltiazem (n = 48) with or without concomitant digoxin therapy at a single university-affiliated teaching hospital. Treatment success was defined as either cardioversion to sinus rhythm or a reduction in the ventricular rate to ≤90 b.p.m. at 24h after the start of therapy. Time to treatment success and the occurrence of adverse effects were considered secondary outcomes. Results: A total of 107 patients with post-CABG AF were treated with i.v. esmolol (n = 59) or i.v. diltiazem (n = 48). The mean maximum dose of esmolol and diltiazem were 115 ± 38 μg/kg/min and 11.2 ± 3.5 mg/h, respectively. The average duration of the esmolol and diltiazem infusions were 19.3 ± 8.5 h and 20.1 ± 11.3 h, respectively. Based on the combined efficacy endpoint of cardioversion or ventricular rate control, esmolol was significantly more effective than diltiazem (90% vs 77%; p = 0.038). Time to treatment success was significantly better for esmolol than diltiazem at all time points (1, 2, 4, 6, 12, and 24 h post-treatment). The overall incidence of adverse effects was 44% with esmolol and 60% with diltiazem (p = 0.04). Rates of drug discontinuance for adverse effects were significantly less for esmolol (20%) compared with diltiazem (38%) (p = 0.04). Conclusions: Esmolol is significantly more effective than diltiazem in the management of post-CABG AF. More patients converted to sinus rhythm with esmolol as compared to diltiazem. Esmolol was associated with fewer adverse effects than diltiazem, including adverse effects leading to drug discontinuance. Due to study design limitations (retrospective data collection), an adequately powered randomised, controlled trial is needed to confirm these preliminary findings.