Effect of Dronedarone on Cardiovascular Events in Atrial Fibrillation

This brief presentation (roughly 25 minutes)-part of the "Groundbreaking Studies in the Practice of Cardiovascular Medicine: Circulation Editors' Choices" session-featured Stefan H. Hohnloser, MD, who presented the results of a study that were published in the February 12, 2009 issue of the New England Journal of Medicine, on behalf of the ATHENA Investigators.

Hohnloser explained they conducted the study at a time when dronedarone was a new antiarrhythmic drug that was being developed for treating atrial fibrillation. The multicenter trial that was carried about by the ATHENA Investigators sought to evaluate dronedarone use in 4628 atrial fibrillation patients who had additional risk factors for death, by randomly assigning them to dronedaron 400mg twice daily or placebo. First hospitalization due to cardiovascular events of death was the primary outcome, with death from any cause, death from cardiovascular causes, and hospitalization due to cardiovascular events as the secondary outcomes.

During a mean follow-up period of 21 months (plus or minus 5 months), continued Hohnloser, treatment was discontinued, mostly due to adverse events, in 30.2% of those who received dronedarone and 30.8% of those who received placebo. Additionally, in 31.9% of the dronedarone group participants and 39.4% of the placebo group, primary outcome was reached, with a hazard ratio of 0.76 for dronedarone. The speaker noted also that 116 deaths occurred within the dronedarone group and 139 in the placebo group, with 63 of those in the dronedarone group and 90 in the placebo group occurring due to cardiovascular causes, mostly because of a reduction in the rate of death from arrhythmia with dronedarone, explained Hohnloser.

Though higher rates of bradycardia, QT-interval prolongation, nausea, diarrhea, rash, and increased serum creatinine levels were seen in the dronedarone group than in the placebo group, thyroid- and pulmonary-related adverse event rates were not significantly different between the groups. Thus, the ATHENA Investigators concluded that dronedarone was able to reduce hospitalizations that occurred as a result of cardiovascular events, as well as reduce death, in atrial fibrillation patients.