Findings from studies suggest that the antiarrhythmic properties of omega-3 fatty acids may play a role in reducing sudden cardiac death.
This study was a randomized, double-blind, placebo-controlled trial in 200 patients (primarily white males) with an implantable cardioverter defibrillator (ICD), a device used to correct aberrant heart rhythms such as ventricular tachycardia (VT) or ventricular fibrillation (VF).
Patients consumed daily either 1.8 grams of fish oil containing 42 percent eicospentaenoic acid and 30 percent docosahexaenoic acid or an olive oil placebo capsule containing 73 percent oleic acid and 12 percent palmitic acid. They were followed for 20 to 828 days (median 718 days). The primary endpoint for the study was the time to the first episode of VT or VF leading to an ICD response. Patients in the fish oil group had significant increases in omega-3 fatty acids in plasma and in red blood cell membranes compared to the placebo group.
For all time points measured (6, 12, and 24 months), patients randomized to fish oil experienced a non-significantly higher ICD response rate. In a subset of VT patients, the incidence of VT/VF treated by the ICD was higher in the fish oil group. Recurrent VT/VF events were also more common in patients randomized to fish oil. While the potential benefit of fish oil may depend on the underlying etiology of the heart disease, additional studies are in progress to define which ICD patients may be at risk from supplemental fish oil.
Funding: National Heart, Lung, and Blood Institute and General Clinical Research Centers Program NIH; and Hoffman-LaRoche Inc.
MH Raitt, WE Connor, C Morris, J Kron, B Halperin, SS Chugh, J McClelland, J Cook, K MacMurdy, R Swenson, SL Connor, G Gerhard, DF Kraemer, D Oscran, C Marchant, D Calhoun, R Shnider, and J McAnulty. Journal of the American Medical Association (JAMA) 2005 293:2884-2891.