Pro- and antiarrhythmic properties of a diet rich in fish oil

Increased consumption of fish rich in omega-3 polyunsaturated fatty acids (omega 3-PUFAs) is associated with decreased incidence of sudden cardiac death in post-myocardial infarction patients, but is also related to increased incidence of sudden death and arrhythmias in patients with acute myocardial ischemia. This review discusses the possible pro- and antiarrhythmic mechanisms of omega 3-PUFAs in relation to various cardiac pathologies. Differences between circulating and incorporated omega 3-PUFAs with respect to electrophysiology are emphasized. We conclude that omega 3-PUFAs alter cardiac electrophysiology and thereby may be pro- or antiarrhythmic, dependent on the mechanism of arrhythmia. As omega 3-PUFAs may be antiarrhythmic under conditions that favour triggered activity, they may facilitate re-entrant arrhythmias. This may explain the contradictory outcomes of increased intake of fish oil on sudden death and arrhythmias in clinical trials. Advice to increase intake of omega 3-PUFA supplements or fatty fish should be tailored to individual patients with respect to the arrhythmogenic mechanisms associated with the underlying pathology. (c) 2006 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.