Fish oil supplements failed to reduce the risk of abnormal heart rhythm in patients with implantable defibrillators, according to a study in this week's Journal of the American Medical Association.
Patients given fish oil and those in the placebo group didn't show a significant difference in the number of episodes of abnormal heart rhythm after two years, in the 200-patient study. Evidence suggests the number of heart-rhythm disturbances may have climbed in patients taking fish oil who had a previous history of too-rapid heart rhythm, the researchers said.
The overwhelming number of sudden deaths from coronary disease, which is estimated at about 335,000 a year, is thought to be caused by an irregular heartbeat disorder called ventricular fibrillation, according to a report on the American Heart Association Web site. Investigators were trying to determine whether fish oil supplements would help reduce both kinds of abnormal heart rhythm in patients with defibrillators.
"The fact that we were not able to demonstrate an antiarrhythmic effect of fish oil does not call into question the potential benefits of fish oil or dietary fish intake in patients who have had a [heart attack]," wrote the study's author Merritt H. Raitt, an associate professor of medicine at the Oregon Health and Science University.