Title

 

Authors

E. Cerbai^1,2, A. Mugelli^1,2,

1Center of Molecular Medicine (C.I.M.M.B.A.) and 2Department of Pharmacology, University of Firenze, Italy

 

Abstract

The role of sarcolemma fatty acid composition on cardiac excitability has received increasing attention in the last years. This is largely due to literature showing that high consumption of fish oil fatty acids can decrease the mortality from sudden cardiac death, although the mechanism(s) of such a protective effect remain elusive. Namely, these studies refer to n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (20:5n-3, EPA) or docosahexaenoic acid (C22:6n-3, DHA), also in comparison with  n-6 PUFAs such as linoleic acid (18:2n-6, LA) and arachidonic acid (C20:4n-6, AA). However, the beneficial effects of n-3 PUFAs on cardiac sudden death is controversial: indeed, increased consumption of fish rich in n-3 polyunsaturated fatty acids has been associated with decreased incidence of sudden cardiac death in post-myocardial infarction patients, but increased incidence of sudden death and arrhythmias in patients with acute myocardial ischemia. Some uncertainties also derive from poor understanding of the effects of n-3 PUFAs on cell excitability and excitation-contraction coupling mechanisms. The presentation will review the possible pro- and antiarrhythmic mechanisms of omega3-PUFAs in cardiac diseases, and differences between circulating and incorporated n3-PUFAs with respect to cardiac cell electrophysiology. Contradictory outcomes of increased intake of fish oil on sudden death and arrhythmias in clinical trials may derive from coexisting pro- or antiarrhythmic effects, possibly related to differences in arrhythmogenic mechanisms such as triggered activity versus re-entrant arrhythmias. In this view, therefore, effects of n3-PUFA supplements or fatty fish may resemble risks and benefits of antiarrhythmic drugs, and increased intake of omega should be tailored to individual patients.