Atrial fibrillation (AF) is the most common complication after cardiac surgery. We aimed to evaluate, by meta-analysis, all randomized trials testing interventions for preventing AF.
Ninety-four trials of prevention of post-operative AF were identified, by standard search methods, and analysed by standard meta-analysis techniques. All five commonly tested interventions, beta-blockers (BBs), sotalol, amiodarone, magnesium, and atrial pacing, were effective in preventing AF. The odds ratio (OR) for the effect of BB on the incidence of AF was 0.36 (95% CI 0.28-0.47, P<0.001), but after trials confounded by post-operative non-study BB withdrawal were excluded was 0.69 (95% CI 0.54-0.87, P=0.002). Sotalol reduced AF, compared with placebo (OR 0.34, 95% CI 0.26-0.45, P<0.001) and compared with conventional BB (OR 0.42, 95% CI 0.26-0.65, P<0.001). Amiodarone reduced AF (OR 0.48, 95% CI 0.40-0.57, P<0.001). Magnesium (Mg) also had an effect (OR 0.57 95% CI 0.42-0.77) but there was significant heterogeneity (P<0.001), partly explained by concomitant BB. The effect of Mg with BB was less (OR 0.83, 95% CI 0.60-1.16). Pacing reduced AF (OR 0.60, 95% CI 0.47-0.77, P<0.001), despite wide variations in techniques. Only amiodarone and pacing significantly reduced length of stay, average -0.60 days (95% CI -0.92 to -0.29) and -1.3 days (95% CI -2.55 to -0.08), respectively. Collectively, all treatments analysed together reduced stroke (OR 0.63, 95% CI 0.41-0.98). Amiodarone was the only intervention that alone significantly reduced stroke rate (OR 0.54, 95% CI 0.30-0.95).
All five interventions reduced the incidence of AF, though the effect of BBs is less than previously thought. The significant reductions in length of stay and stroke in meta-analysis suggest that there are worthwhile benefits from aggressive prevention. Larger studies to confirm these clinical benefits and evaluate their cost-effectiveness would be worthwhile.