The composite of all-cause mortality, non-fatal stroke, non-fatal AMI, systemic embolism, heart failure development or severe bleeding occurred in 20 (6.7 percent) and 16 (5.5 percent) patients randomized to placebo or n-3 PUFA, respectively (HR 0.86; 0.44-1.66; p=0.65).

OPERA, which looked at 1,516 patients, had similar results. Data showed that the primary endpoint of occurrence of postoperative AFib lasting longer than 30 seconds occurred in 233 (30.7 percent) of patients assigned to placebo and 227 (30 percent) of patients assigned to n-3 PUFAs (odds ratio, 0.96 [95 percent CI, 0.77-1.20]; P=.74). In addition, none of the secondary endpoints of postoperative AFib lasting longer than one hour, resulting in symptoms, or treated with cardioversion, were significantly different between the placebo and fist oil groups, including post-operative AFib that was sustained, symptomatic or treated (231 [30.5 percent] vs. 224 [29.6 percent], P=.70) or number of postoperative AFib episodes per patient (one episode: 156 [20.6 percent] vs. 157 [20.7 percent]; two episodes: 59 [7.8 percent] vs. 49 [6.5 percent]; ≥three episodes: 18 [2.4 percent] vs. 21 [2.8 percent], P=.73).

The authors note that previous smaller trials found mixed effects of perioperative n-3 PUFAs on postoperative AFib, but that the OPERA trial comprised of more patients and AFib events than all of the prior trials combines. "Our findings and those of prior studies highlight the need for meticulous investigation of the underlying physiological, structural, and molecular underpinning of postoperative AFib to allow novel targeted preventive and therapeutic interventions," they said. FORWARD investigators had a similar conclusion, noting that their results and those from other previous studies continue to indicate there is no role of n-3 PUFA for the secondary prevention of AFib.