Fish Oil Supplementation and Risk of Ventricular Tachycardia and Ventricular Fibrillation in Patients With Implantable Defibrillators

Abstract

INCE THE ORIGINAL OBSERVAtions that Greenland Eskimos eating a diet high in omega-3 polyunsaturated fats (PUFAs) from sea mammals and fish had an unexpectedly low risk of cardiac death, 1,2 multiple lines of evidence have suggested that omega-3 PUFAs have antiarrhythmic properties. Four randomized clinical trials 3-6 have shown that dietary changes or supplements to increase omega-3 PUFA intake result in a reduced risk of sudden death without a consistent change in risk of myocardial infarction. To test the hy

The Mediterranean-style diet for the prevention of cardiovascular diseases

“…Finally, in a recent trial conducted in patients with implantable cardiac defibrillator, Leaf reported a 40% reduction of recurrent ventricular arrhythmias following fish oil capsules in a double blinded trial 30 . It is noteworthy, however, that in another recent publication reporting fish oil supplementation in the same type of patients, the results were negative 31 . Beside major technical limitations (too small sample size resulting in randomised groups not well balanced for some baseline risk factors and under-powered statistical analyses) especially in one trial with only 200 patients 31 , there is no clear explanation for that discrepancy between trials.…”

“…It is noteworthy, however, that in another recent publication reporting fish oil supplementation in the same type of patients, the results were negative 31 . Beside major technical limitations (too small sample size resulting in randomised groups not well balanced for some baseline risk factors and under-powered statistical analyses) especially in one trial with only 200 patients 31 , there is no clear explanation for that discrepancy between trials. Obviously, some major dietary confounders (background marine and plant omega-3 fatty acid intake, omega-6 fatty acid intake, trans fatty acid intake, saturated fatty acid intake), which could greatly interfere with the omega-3 fatty acids given with the capsules, were curiously not measured in these trials and not included (for minimal adjustments) in the calculations of the risks.…”

n-3 Fatty acids and cardiovascular disease: Actions and molecular mechanisms

“…However contrasting results have been reported in patients with implantable cardioverter defibrillators [24][25][26] and it is possible that n-3 FA increase risk of re-entrant tachycardia in a small and specific subset of individuals with a slow re-entrant arrhythmic loop around a region of scarred myocardium [23].…”

Omega-3 Fatty Acids and Cardiovascular Disease

“…However, in Kowey et al's trial [37] of 663 AF patients, omega-3 supplementation did not reduce the recurrence of AF in the 6 month study period. Others have described trends towards reduction in malignant ventricular arrhythmias with omega-3 supplementation [10, [38][39][40]. Although omega-3 fatty acids appear to be effective for reducing SCD in the setting of CHD with reduced left ventricular systolic function [41], 3 trials using omega-3 fatty acids in implantable cardioverter defibrillator patients have shown mixed results [38][39][40].…”

“…Others have described trends towards reduction in malignant ventricular arrhythmias with omega-3 supplementation [10, [38][39][40]. Although omega-3 fatty acids appear to be effective for reducing SCD in the setting of CHD with reduced left ventricular systolic function [41], 3 trials using omega-3 fatty acids in implantable cardioverter defibrillator patients have shown mixed results [38][39][40]. The most recent trial evaluating major arrhythmic events was a substudy of the GISSI Heart Failure (HF) trial that showed fewer events in the omega-3 arm, but this finding was not statistically significant [42].…”