Fish Oil Supplementation Does Not Prevent Irregular Heart Rhythm after Surgery

According to late-breaking clinical trial results presented at the American Heart Association 2012 Scientific Sessions, short-term fish oil supplementation does not decrease atrial fibrillation in patients that have had heart surgery.

Recent studies have recommended that eating fish or supplementing your daily diet with fish oil may lower atrial fibrillation risk. Atrial fibrillation occurs in nearly one-third of patients who have had heart surgery, and can cause a stroke.

Results from the OPERA study were published in JAMA in an article titled, “Fish Oil and Postoperative Atrial Fibrillation: The Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrilliation (OPERA) Randomized trial.” OPERA is a randomized, double-blind, placebo-controlled clinical trial that investigated the effects of fish oil supplementation on risk of post-operative atrial fibrillation.

In the study, researchers in the United States, Argentina, and Italy studied 1,516 patients (mean age 64 years old) who were undergoing heart surgery between August 2010 and June 2012. Seventy-two percent of the patients were male, 41% were undergoing bypass surgery alone, 52% had valve surgery, with or without coronary bypass, and 7% underwent other cardiac surgery.

The patients received either a placebo supplement or supplements containing 10 grams of n-3-polyunsaturated fatty acids (PUFAs) 3-5 days before surgery, or 8 grams over two days, and 2 grams daily for 10 days post-surgery or until they were discharged from the hospital.

The primary endpoint (occurrence of post-operative atrial fibrillation of at least 30 seconds’ duration and documented by rhythm strip or 12-lead ECG) occurred in 233 patients (30.7%) in the placebo group and 227 (30.0%) in the group that received n-3-PUFAs.

The study revealed that most cases of post-operative atrial fibrillation occurred between one and four days after surgery. Researchers reported no difference between either group in the number of post-operative heart attacks or stroke, There was also no difference in the number of patients who died within 30 days post-surgery, and no difference in the number of days in the ICU post-surgery. The use of fish oil supplements did not cause any increased bleeding risks.

“Omega-3 polyunsaturated fatty acids may offer a number of protective effects to prevent cardiovasular disease, but if you look at this particular population of surgical patients and their short-term use, fish oil does not help avoid atrial fibrillation,” said Dariush Mozaffarian, MD, DrPH, associate professor of medicine at the Harvard Medical School.

“Further research should examine whether long-term fish oil consumption helps prevent atrial fibrillation in elderly adults with high blood pressure, said Roberto Marchioli, MD, MPH, the study’s co-author, and head of the Laboratory of Clinical Epidemiology of Cardiovascular Disease, Consorzio Mario Negri Sud in Santa Maria Imbaro, Italy.