Fish Oil for the Reduction of Atrial Fibrillation Recurrence, Inflammation, and Oxidative Stress

Study Questions:

Does high-dose fish oil supplementation improve inflammation and oxidative stress, and reduce atrial fibrillation (AFib) occurrence?


Data from the Multi-center Study to Evaluate the Effect of N-3 Fatty Acids (OMEGA-3) on Arrhythmia Recurrence in Atrial Fibrillation (AFFORD) were used for the present analysis. This was a double-blind, randomized, placebo-controlled, parallel-arm study, which enrolled patients with AFib. AFib had to be symptomatic paroxysmal or persistent AFib occurring within 6 months of enrollment. Participants were randomized to fish oil (4 g/day) or placebo and followed, on average, for 271 ± 129 days. The primary outcome of interest was time to first symptomatic or asymptomatic AFib recurrence lasting >30 seconds. Secondary outcomes included markers of inflammation and oxidative stress (high-sensitivity C-reactive protein and myeloperoxidase).


A total of 337 patients were enrolled in AFFORD, of which 297 (88%) completed the study. No differences in dropout rates were noted between the study arms. Baseline characteristics were similar between the two groups. The primary endpoint occurred in 64.1% of patients in the fish oil arm and 63.2% of patients in the placebo arm (hazard ratio, 1.10; 95% confidence interval, 0.84-1.45; p = 0.48). High-sensitivity C-reactive protein and myeloperoxidase were within normal limits at baseline and decreased to a similar degree at 6 months (p value for interaction = nonsignificant).


The authors concluded that high-dose fish oil does not reduce AFib recurrence in patients with a history of AFib not receiving conventional antiarrhythmic therapy. Furthermore, fish oil does not reduce inflammation or oxidative stress markers in this population, which may explain its lack of efficacy.


These data suggest that omega-3 fatty acids do little to reduce the burden of AFib. Further research in other therapies which have potential to reduce AFib is warranted, given the projected increase in AFib over the next several decades.

Clinical Topics: Arrhythmias and Clinical EP, Dyslipidemia, Prevention, Atrial Fibrillation/Supraventricular Arrhythmias, Lipid Metabolism, Nonstatins, Diet, Stress

Keywords: Inflammation, Recurrence, Fish Oils, Dietary Supplements, Fatty Acids, Omega-3, Peroxidase, Oxidative Stress, Atrial Fibrillation

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