Fish oils, principally omega-3 fatty acids, have previously been investigated as a potential anti-arrhythmic agent for patients suffering from atrial fibrillation. However, the results of several small trials performed to date have been unclear. Therefore this randomised trial was designed to assess the effect of omega-3 fatty acids on patients with paroxysmal or persisting atrial fibrillation without structural heart disease.

Six hundred and sixty-three patients with atrial fibrillation were recruited over a three year period; all were in sinus rhythm at the time of recruitment but were known to have either paroxysmal (n=542) or persistent (n=121) atrial fibrillation. Patients were randomised to either placebo or omega-3 treatment and followed up for 24 weeks. The primary outcome measure was symptomatic recurrence of atrial fibrillation.

At 4 and 24 weeks, both eicosapentaenoic acid and docosahexaenoic acid levels were raised in the treatment group compared to the control group. However, no difference was noted between treatment groups for recurrence of symptomatic AF in the paroxysmal stratum (HR, 1.15; 95% CI 0.90 to 1.46; p=0.26), in the persistent stratum (HR, 1.64; 95% CI 0.92 to 2.92; p=0.09), or both strata combined (HR, 1.22; 95% CI 0.98 to 1.52; p=0.08).

Conclusions

In this randomised study, treatment with omega-3 did not reduce the incidence of paroxysmal atrial fibrillation over a six-month period. Other larger trials examining the effect of fish oils on atrial fibrillation are ongoing.

▶ Kowey PR, Reiffel JA, Ellenbogen KA, et al. Efficacy and safety of prescription omega-3 fatty acids for the prevention of recurrent symptomatic atrial fibrillation. A randomized controlled trial.JAMA 2010;304:2363–72.