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

Abstract

Increased consumption of fish rich in omega-3 polyunsaturated fatty acids (omega3-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 omega3-PUFAs in relation to various cardiac pathologies. Differences between circulating and incorporated omega3-PUFAs with respect to electrophysiology are emphasized. We conclude that omega3-PUFAs alter cardiac electrophysiology and thereby may be pro- or antiarrhythmic, dependent on the mechanism of arrhythmia. As omega3-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 omega3-PUFA supplements or fatty fish should be tailored to individual patients with respect to the arrhythmogenic mechanisms associated with the underlying pathology.

Ultrafast sodium channel block by dietary fish oil prevents dofetilide-induced ventricular arrhythmias in rabbit hearts

“…However, contrary to reports of the beneficial effects of 3FA consumption or supplements on cardiac deaths in some populations (14), other trials have suggested a neutral effect in patients with implanted cardioverter defibrillators (7,35) and even a deleterious effect in men with angina (8). It is unclear whether these contradictory observations on the effects of 3FA supplementation can be accounted for by different population characteristics (e.g., angina vs. post-myocardial infarction or heart failure), possible toxic effects of mercury exposure associated with fish intake, background fish consumption in the control population, or the type of arrhythmogenic mechanism (e.g., triggered activity vs. reentry arrhythmias) (12).…”

Omega-3 Polyunsaturated Fatty Acids Prevent Atrial Fibrillation Associated With Heart Failure but Not Atrial Tachycardia Remodeling

“…Acutely administered PUFAs have a number of effects on cardiac ion channels and transporters, which may differ in important ways from chronically administered PUFAs that are gradually incorporated into the cell membrane. 11 PUFAs may have complex effects that are proarrhythmic, antiarrhythmic, or neutral, depending on the mode of administration and arrhythmia mechanism. 11,12 Acutely administered PUFAs have been reported to reduce stretch-induced susceptibility to AF in isolated rabbit hearts 13 and to suppress short-term (several-hour) atrial tachycardia remodeling in dogs.…”

“…11 PUFAs may have complex effects that are proarrhythmic, antiarrhythmic, or neutral, depending on the mode of administration and arrhythmia mechanism. 11,12 Acutely administered PUFAs have been reported to reduce stretch-induced susceptibility to AF in isolated rabbit hearts 13 and to suppress short-term (several-hour) atrial tachycardia remodeling in dogs. 14 However, no published information is available on sustained oral PUFA administration, as occurs with dietary fish oil, on animal models of clinically relevant AF substrates like those induced by longer-term atrial tachypacing (ATP) and ventricular tachypacing (VTP)-induced congestive heart failure (CHF).…”

Response to Letter Regarding Article “Acute Administration of Fish Oil Inhibits Triggered Activity in Isolated Myocytes From Rabbits and Patients With Heart Failure”

“…2 We cannot exclude I Na,P in human myocytes, although similarity of the response to 3-polyunsaturated fatty acids makes species differences less probable. In addition, reductions in [Ca 2ϩ ] i levels after application of 3-polyunsaturated fatty acids have been observed in isolated myocytes from both healthy and diseased hearts 1,3,4 and are therefore likely independent of I Na,P .…”

“…[3][4][5] Therefore, we excluded the possibility that the antiarrhythmic mechanism of 3-polyunsaturated fatty acids is related to inhibition of I Na,P , at least in the rabbit model of heart failure.…”