Omega-3 fatty acids and prevention of ventricular fibrillation

Interest in the potential cardiovascular benefits of omega-3 long chain polyunsaturated fatty acids has been largely focused on possible antiatherothrombotic effects. In addition, however, definitive antiarrhythmic effects of these dietary omega-3 fatty acids have been reported by Charnock & McLennan. Our studies commenced with the observation that two of these fatty acids, eicosapentaenoic (C20:5n-3, EPA) and docosahexaenoic acid (C22:6n-3, DHA) prevented contracture and fibrillation of isolated neonatal cardiac myocytes when exposed to toxic levels of ouabain (0.1 mM). This protection was associated with prevention of excessively high intracellular calcium concentrations in the myocyte. Further, it was shown that these fatty acids modulate calcium currents through L-type calcium channels and that the effect occurs within a few minutes of adding EPA or DHA to the medium perfusing the cultured cardiac myocytes. Infusing an emulsion of the omega-3 fatty acids intravenously just prior to compression of a coronary artery in a conscious, prepared dog will prevent the expected subsequent ischemia-induced ventricular fibrillation.