An editorial in the June 3 issue of Circulation calls attention to the clinical implications of research related to n-3 polyunsaturated fatty acids (PUFAs), myocardial vulnerability, and sudden cardiac death. Studies using a variety of research paradigms now suggest that a modest intake of the n-3 polyunsaturated fatty acids from fatty fish may reduce mortality from sudden cardiac death.
The editorial writers are from the UWs Cardiovascular Health Research Unit and the Veterans Affairs Puget Sound Health Care System. They are David Siscovick, professor of medicine and of epidemiology, Rozenn Lemaitre, research scientist in the Division of General Internal Medicine, and Dariush Mozaffarian, a senior fellow in the Department of Medicine.
The writers outlined a new diet-heart hypothesis: Dietary n-3 polyunsaturated fatty acid intake increases cell membrane and free fatty acid n-3 polyunsaturated fatty acid levels. The higher n-3 PUFA levels alter cardiac ion channel function. The altered ion channel function modifies cardiac action potential, and thereby reduces the hearts vulnerability to ventricular fibrillation, the life-threatening arrhythmia that results in sudden cardiac death.
Few drug therapies have been shown to reduce the risk of sudden cardiac death. The editorial authors note that, for the public, a dietary intake of modest amounts of n-3 polyunsaturated fatty acids from seafood (the equivalent of one fatty fish meal a week), and,for patients with a prior myocardial infarction, a low dose n-3 PUFA supplement (850 mg per day of EPA/DHA) are low-cost, low-risk interventions that are likely to reduce the risk of sudden cardiac death.