Effect of fish oil on ventricular tachyarrhythmia in three studies in patients with implantable cardioverter defibrillators

To determine the effects of omega-3 polyunsaturated fatty acids (omega-3 PUFAs) from fish on the incidence of recurrent ventricular arrhythmia in implantable cardioverter defibrillator (ICD) patients by combining results from published trials. We searched in the Medline, EMBASE, and Cochrane databases and performed a meta-analysis on all three available trials on fish oil and ventricular arrhythmia. Furthermore, we pooled individual data of two of these randomized, double-blind, placebo-controlled trials (Raitt et al. Fish oil supplementation and risk of ventricular tachycardia and ventricular fibrillation in patients with implantable defibrillators: a randomized controlled trial. JAMA 2005;293:2884-2891 and Brouwer et al. Effect of fish oil on ventricular tachyarrhythmia and death in patients with implantable cardioverter defibrillators: the Study on Omega-3 Fatty Acids and Ventricular Arrhythmia (SOFA) randomized trial. JAMA 2006;295:2613-2619). The main outcome was time to first confirmed ventricular fibrillation (VF) or ventricular tachycardia (VT) combined with death for the meta-analysis, and time to first spontaneous confirmed VF or VT for the pooled analysis. The meta-analysis (n = 1148) showed no convincing protective effect of fish oil (RR 0.90; 95% CI 0.67-1.22). The hazard ratio for the subgroup of patients with coronary artery disease at baseline (0.79; 0.60-1.06) tended towards a protective effect. The pooled analysis (n = 722) showed that time to appropriate ICD intervention was similar for fish oil and placebo treatment (log-rank P = 0.79). These findings do not support a protective effect of omega-3 PUFAs from fish oil on cardiac arrhythmia in all patients with an ICD. Current data neither prove nor disprove a beneficial or a detrimental effect for subgroups of patients with specific underlying pathologies.