A Cochrane review on antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation included 59 studies with a total of 21 305 subjects. Dronedarone was included in 4 of the studies with a total of 6 568 subjects.
Compared to placebo dronedarone reduced atrial fibrillation recurrence (Peto OR 0.59, 95% CI 0.46 to 0.75; 2 studies, n=1 443). Dronedarone showed no significant difference in mortality compared with placebo (Peto OR 0.85, 95% CI 0.67 to 1.09; 3 studies, n=6 071) and dronedarone increased withdrawals due to adverse effects (OR 1.64, 95% CI 1.38 to 1.94; 3 studies, n=6 071).
In direct comparisons between antiarrhythmics amiodarone reduced recurrences of atrial fibrillation significantly more than dronedarone (OR 0.45, 95% CI 0.31 to 0.63; 1 study, n=504).
Pooled recurrence rates of atrial fibrillation at 1 year were high: 69% to 84% in controls not receiving antiarrhythmic treatment, reduced to 43% to 67% in patients treated with antiarrhythmics. The corresponding average NNT for 1 year, to avoid 1 recurrence of atrial fibrillation, were 3 with amiodarone, 4 with flecainide, 5 with dofetilide and propafenone, 8 with quinidine and sotalol and 9 with dronedarone and metoprolol and 17 with azimilide (the 95% CI varied between 2 and 60).