Omega-3 fatty acid supplements don't cut back on recurrences of atrial fibrillation, a type of irregular heartbeat that can cause stroke, new research suggests. "We now have definitive data that they don't work for most patients with AF," said Dr. Peter R. Kowey, lead author of a study appearing in the Dec. 1 issue of the Journal of the American Medical Association that is also scheduled to be presented Monday at the American Heart Association's annual meeting in Chicago. "Although we can't exclude the possibility of efficacy in sicker AF patients, it would be hard to believe that it would work in that population and not in healthier patients. So for practical purposes, yes, the end of the line in AF."
This study, the largest of its kind, looked at patients with AF who were otherwise healthy. "We cannot say there is any convincing evidence of a role for omega-3 in the prevention of atrial fibrillation," added Dr. Ranjit Suri, director of the Electrophysiology Service and Cardiac Arrhythmia Center at Lenox Hill Hospital in New York City, who was not involved with the trial. The study was funded by GlaxoSmithKline. Omega-3 fatty acids, which are found in fatty fish such as salmon and albacore tuna, had showed some promise in preventing heart disease in earlier trials. Of the total 663 outpatient participants, 542 had paroxysmal atrial fibrillation, which appears suddenly and resolves on its own, and 121 had persistent atrial fibrillation, which needs treatment.
Participants were randomized to receive either a placebo or 8 grams of omega-3 supplements daily for the first week, followed by 4 grams a day for the remaining 23 weeks of the trial. The doses used in the study are available only by prescription and are "higher than doses previously published in studies," said Dr. Robert Block, a cardiologist and assistant professor of community and preventive medicine at the University of Rochester Medical Center. At the end of six months, 46 percent of those in the placebo group and 52 percent of those taking omega-3 supplements experienced recurrences. The numbers of paroxysmal AF patients in the placebo and treatment groups who had AF recurrences were about equal, the investigators found.