A Randomized, Placebo-Controlled Trial of Omega-3 Fatty Acids for Inhibition of Supraventricular Arrhythmias After Cardiac Surgery: The FISH Trial

Background-Omega-3 polyunsaturated fatty acids (n3-PUFAs) might have antiarrhythmic properties, but data conflict on whether n3-PUFAs reduce rates of atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG). We hypothesized that n3-PUFAs would reduce post-CABG AF, and we tested this hypothesis in a well-powered, randomized, double-blind, placebo-controlled, multicenter clinical trial. Methods and Results-Patients undergoing CABG were randomized to pharmaceutical-grade n3-PUFAs 2 g orally twice daily (minimum of 6 g) or a matched placebo >= 24 hours before surgery. Gas chromatography was used to assess plasma fatty acid composition of samples collected on the day of screening, day of surgery, and postoperative day 4. Treatment continued either until the primary end point, clinically significant AF requiring treatment, occurred or for a maximum of 2 weeks after surgery. Two hundred sixty patients were enrolled and randomized. Before surgery, n3-PUFA dosing increased plasma n3-PUFA levels from 2.9% to 4% and reduced the n6:n3-PUFA ratio from 9.1 to 6.4 (both P<0.001). Similar changes were noted on postoperative day 4. There were no lipid changes in the placebo group. The rate of post-CABG AF was similar in both groups (30% n3-PUFAs versus 33% placebo, P=0.67). The post-CABG AF odds ratio for n3-PUFAs relative to placebo was 0.89 (95% confidence interval 0.52-1.53). There were no differences in any secondary end points. Conclusions-Oral n3-PUFA supplementation begun 2 days before CABG did not reduce AF or other complications after surgery.