WEDNESDAY, May 4, 2005 (HealthDay News) -- New guidance about the best use of two drugs widely prescribed for atrial fibrillation, a type of abnormal heartbeat, has arrived in a major nationwide study.
The drugs, amiodarone (Cordarone) and sotalol (Betapace) help restore a normal heartbeat for people with atrial fibrillation, in which the two upper chambers of the heart lose their regular rhythm, sometimes fluttering uselessly rather than pumping blood.
The study found that both drugs work equally well in controlling cardiac rhythm, although amiodarone may have an edge when it comes to treating patients with a specific type of heart disease.
The American Heart Association estimates that 2.2 million Americans, many of them elderly, have atrial fibrillation. They are at higher risk of strokes caused by the clots that can form when blood pools in the atria. Clot-preventing drugs are often prescribed, but many patients get one of the two rhythm-restoring drugs, as well.
The study included 665 atrial fibrillation patients treated at Department of Veterans Affairs medical centers from California to Rhode Island. All were already taking clot-preventing drugs because of persistent atrial fibrillation. Of the group, 267 received amiodarone, 261 were given sotalol and 137 received a placebo. All were monitored for as long as 4.5 years, with researchers measuring the time it took for their atrial fibrillation to recur after normal heartbeat was restored.
The study, reported in the May 5 issue of the New England Journal of Medicine, found benefits from both drugs when compared to placebo. But there was a difference in results between patients with ischemic heart disease, in which coronary arteries are partially blocked, versus those with clear coronary arteries.
Restoring normal heartbeat "significantly improved the quality of life and exercise capacity" of the participants, the researchers reported. Both drugs had about the same success in restoring normal heartbeat -- 27.1 percent of those receiving amiodarone and 24.2 percent of those getting sotalol got back into a more regular rhythm compared to just 0.8 percent of those receiving a placebo.
But amiodarone worked better for people with ischemic heart disease, keeping heartbeat normal for an average of 569 days, compared to 428 days for heart patients without this condition.
"This study is telling me that both medications are equally effective in the overall group, but that amiodarone is better for patients with ischemic heart disease," said Dr. Walid Sliba, a cardiologist at the Cleveland Clinic who specializes in arrhythmia. "Without ischemic heart disease, maybe sotalol is better."
Previous, smaller studies have reported similar results, Sliba said, but the new one "adds more sound evidence based on a larger trial."
The findings are one piece of a very large picture, Sliba added. "The problem is that when it comes to treatment of atrial fibrillation, you have a long laundry list of medications you can use," he said.
That assessment was confirmed by Dr. David A. Meyerson, a cardiologist at Johns Hopkins University and a spokesman for the American Heart Association.
"While previous studies have shown that patients with atrial fibrillation can be safely managed with rate control and anticoagulation [clot prevention], certain patients remain better served by restoring normal rhythm," Meyerson said. "This study confirms our long-held clinical belief that amiodarone is somewhat better than sotalol in preventing the recurrence of atrial fibrillation."
But since "a medicine that works well for some may not be suitable for all, both medications retain significant utility in clinical practice," he said.
Atrial fibrillation and its various treatments are described by the American Heart Association.