AHA 2010: Prescription Omega-3 Useless in Atrial Fibrillation

Atrial fibrillation (AF) is common and usually requires therapy, yet current treatments have limited efficacy and untoward side effects. Data from several small trials have suggested that antiarrhythmic benefits of omega-3 polyunsaturated fatty acids may be safe and effective in this patient population. However, study results presented at the AHA scientific Sessions 2010 demonstrate that prescription omega-3 has little preventive benefit in patients with atrial fibrillation.

Researchers led by Peter Kowey, MD, Main Line Health Heart Center Lankenau Hospital, Wynnewood, PA, conducted “Efficacy and Safety of Prescription Omega-3 Acid Ethyl Esters (P-OM3) for the Prevention of Recurrent Symptomatic Atrial Fibrillation,” a prospective, randomized double-blind study to evaluate the safety and efficacy of P-OM3 in patients with confirmed symptomatic paroxysmal or persistent AF.

“The rationale for this study was that many of our patients do use fish oil products in various doses and preparations in the hope of preventing several CV endpoints,” Kowey said in a press conference in Chicago for the American Heart Association Scientific Sessions 2010. “There clearly has been equipoise in the area of AF with as many studies producing positive results as those producing negative results.” The study found no benefit of P-OM3 for the prevention of recurrent AF in subjects without significant structural heart disease.

Subjects with symptomatic AF without significant structural heart disease were eligible for the study. Concomitant antiarrhythmic drugs were not allowed. A total of 663 patients with paroxysmal or persistent AF were randomly assigned to P-OM3 4g/d or placebo and treated for 24 weeks. The treatment groups and strata were well-matched with regard to demographics and baseline characteristics and had a mean age of 61 years, was 56% male, with 67% concomitant beta blocker use, 45% statin use, and 39% ACE/ARB use. Sixty-two percent had hypertension, 17% had coronary artery disease and 3% had clinically significant abnormal baseline ECHO.

There was no difference between treatment groups in the time to first recurrence of symptomatic AF in the paroxysmal stratum and both groups combined. P-OM3 was safe and well-tolerated; 5% of placebo and 4% of P-OM3-treated patients discontinued due to adverse events.

Kowey said the basis for the study was that the researchers thought there were problems with previous studies -- that they were somewhat underpowered and didn’t deliver enough of the drug. “We went out of our way to deliver a large dose of prescription grade fatty acid esters and wanted to see if it would work for people with common garden-variety atrial fibrillation,” Kowey said. “We were successful in delivering the drug; there was great compliance with the drug. The long and the short of it was it didn’t work. So we think it’s unlikely this will become a mainstream therapy for atrial fibrillation.”

Eating fish rich in omega-3 fatty acids benefits patients with some types of heart problems, including heart failure and heart attack. As part of a heart healthy diet, it is associated with reduced risk of sudden death and death from coronary artery disease in adults.

The findings of this study don’t relate to omega-3 ingested from fish, Kowey said. “This was not a dietary study; this was a product manufactured from fish oil.” Some 2.66 million Americans currently have one of three forms of atrial fibrillation -- paroxysmal, persistent and permanent -- that increase the risk of fatal coronary heart disease, heart failure and stroke.