Effect of Dronedarone on Cardiovascular Events in Atrial Fibrillation

Background Dronedarone is a new antiarrhythmic drug that is being developed for the treatment of patients with atrial fibrillation. Methods We conducted a multicenter trial to evaluate the use of dronedarone in 4628 patients with atrial fibrillation who had additional risk factors for death. Patients were randomly assigned to receive dronedarone, 400 mg twice a day, or placebo. The primary outcome was the first hospitalization due to cardiovascular events or death. Secondary outcomes were death from any cause, death from cardiovascular causes, and hospitalization due to cardiovascular events. Results The mean follow- up period was 21 +/- 5 months, with the study drug discontinued prematurely in 696 of the 2301 patients ( 30.2%) receiving dronedarone and in 716 of the 2327 patients ( 30.8%) receiving placebo, mostly because of adverse events. The primary outcome occurred in 734 patients ( 31.9%) in the dronedarone group and in 917 patients ( 39.4%) in the placebo group, with a hazard ratio for dronedarone of 0.76 ( 95% confidence interval [ CI], 0.69 to 0.84; P< 0.001). There were 116 deaths ( 5.0%) in the dronedarone group and 139 ( 6.0%) in the placebo group ( hazard ratio, 0.84; 95% CI, 0.66 to 1.08; P = 0.18). There were 63 deaths from cardiovascular causes ( 2.7%) in the dronedarone group and 90 ( 3.9%) in the placebo group ( hazard ratio, 0.71; 95% CI, 0.51 to 0.98; P = 0.03), largely due to a reduction in the rate of death from arrhythmia with dronedarone. The dronedarone group had higher rates of bradycardia, QT- interval prolongation, nausea, diarrhea, rash, and an increased serum creatinine level than the placebo group. Rates of thyroid- and pulmonary- related adverse events were not significantly different between the two groups. Conclusion Dronedarone reduced the incidence of hospitalization due to cardiovascular events or death in patients with atrial fibrillation. (ClinicalTrials. gov number, NCT00174785.).