Dronedarone is a multi-channel-blocking drug for the treatment of patients with atrial
fibrillation (AF) or atrial flutter (AFL) with rate- and rhythm-controlling properties. A
Placebo-Controlled, Double-Blind, Parallel Arm Trial to Assess the Efficacy of Dronedarone
400 mg b.i.d. for the Prevention of Cardiovascular Hospitalization or Death from Any
Cause in Patients With Atrial Fibrillation/Atrial Flutter (ATHENA) demonstrated that
dronedarone reduced the risk for first cardiovascular hospitalization or death from any
cause. The aim of this post hoc analysis was to evaluate the rhythm- and rate-controlling
properties of dronedarone in the ATHENA trial. Patients were randomized to dronedarone
400 mg twice daily (n 2,301) or placebo (n 2,327). Electrocardiographic tracings were
classified for AF or AFL or sinus rhythm. Patients with AF or AFL on every postbaseline
electrocardiogram were classified as having permanent AF or AFL. All electrical cardioversions
were documented. The use of rate-controlling medications was equally distributed
in the 2 treatment groups. The median time to first AF or AFL recurrence of patients in sinus
rhythm at baseline was 498 days in placebo patients and 737 days in dronedarone patients
(hazard ratio 0.749, 95% confidence interval 0.681 to 0.824, p <0.001). In the dronedarone
group, 339 patients (15%) had >1 electrical cardioversion, compared to 481 (21%) in the
placebo group (hazard ratio 0.684, 95% confidence interval 0.596 to 0.786, p <0.001). The
likelihood of permanent AF or AFL was lower with dronedarone (178 patients [7.6%])
compared to placebo (295 patients [12.8%]) (p <0.001). At the time of first AF or AFL
recurrence, the mean heart rates were 85.3 and 95.5 beats/min in the dronedarone and
placebo groups, respectively (p <0.001). In conclusion, dronedarone demonstrated both
rhythm- and rate-controlling properties in ATHENA. These effects are likely to contribute
to the reduction of important clinical outcomes observed in this trial.