Even though previous research has shown that fatty acids from fish oil reduce the risk of sudden cardiac death, patients with implantable defibrillators who took fish oil supplements did not see a reduction in serious heart rhythm abnormalities, according to a study in the June 15 issue of JAMA: The Journal of the American Medical Association.
Since the original observations that Greenland Eskimos eating a diet high in omega-3 polyunsaturated fats (PUFAs) from sea mammals and fish had an unexpectedly low risk of cardiac death, multiple lines of evidence have suggested that omega-3 PUFAs have antiarrhythmic properties, according to background information in the article. Several clinical trials have shown that dietary changes or supplements to increase omega-3 PUFA intake result in a reduced risk of sudden death without a consistent change in risk of heart attack.
Merritt H. Raitt, M.D., of Oregon Health and Science University and the Portland VA Medical Center, Portland, Ore., and colleagues conducted a study to determine if fish oil supplements would have antiarrhythmic properties in patients with a recent episode of sustained ventricular arrhythmia. The double-blind, placebo-controlled trial was performed at 6 U.S. medical centers with enrollment from February 1999 until January 2003. The study included 200 patients with an implantable cardioverter defibrillator (ICD) and a recent episode of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Patients were randomly assigned to receive fish oil, 1.8 g/d, 72 percent omega-3 PUFAs, or placebo and were followed up for a median of 718 days.