P-OM3: Prescription omega-3 no more effective than placebo for paroxysmal atrial fibrillation treatment

American Heart Association Scientific Sessions 2010

CHICAGO — Researchers of the P-OM3 trial have reported that prescription omega-3 was no more beneficial for patients with paroxysmal atrial fibrillation than placebo for the recurrence of symptomatic atrial fibrillation.

“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 cardiovascular endpoints,” researcher Peter Kowey, MD, with the Jefferson Medical College, Philadelphia, said in a press conference. “There clearly has been equipoise in the area of atrial fibrillation with as many studies producing positive as those producing negative results.”

In the prospective, randomized, double blind, placebo-controlled study, 663 patients (paroxysmal atrial fibrillation, (n=542; persistent atrial fibrillation, n=121) were assigned to either P-OM3 (Lovaza, GlaxoSmithKline) 4 g daily or placebo and treated for 24 weeks. Patients had no substantial structural heart disease and normal sinus rhythm at baseline and were recruited from 96 sites in the United States between November 2006 and July 2009. The primary outcome was the time to first recurrence of symptomatic atrial fibrillation (including flutter) in subjects with paroxysmal atrial fibrillation.

At the final follow-up in January of this year, there were no significant differences between treatment groups for recurrence of symptomatic atrial fibrillation in the following strata: paroxysmal (HR=1.15; 95% CI, 0.90-1.46), persistent (HR=1.64; 95% CI, 0.92-2.92), and paroxysmal and persistent combined (HR=1.22; 95% CI, 0.98-1.52). The secondary endpoints, including time to first onset of symptomatic atrial fibrillation (excluding flutter; P=.21) and first recurrence of symptomatic or asymptomatic atrial fibrillation or flutter (P=.33), also supported the primary outcome.

“I don’t think there is any ambiguity about the results in this trial [when] looking at patients with paroxysmal atrial fibrillation that the use of high doses of omega-3 fatty acids did not appear to have a significant effect on recurrence of atrial fibrillation,” Kowey said in an interview. “This doesn’t apply to other populations or other CV disease, but I think we’ve put this issue to rest in this particular population.”

These are data we needed sorely because there are a lot of patients who have taken these prescription omega-3 fatty acids.
There are still some questions. Are there some types of atrial fibrillation that have a benefit? One of these is postoperative atrial fibrillation because there is a lot of inflammation. Because the benefit could be seen more in older patients or patients with structural heart disease, perhaps omega-3 fatty acid might have benefit there. Also, this wasn’t a test of persistent or chronic atrial fibrillation.
Right now, the take home point is that we really don’t have the evidence that omega-3 fatty acids prevent symptomatic atrial fibrillation in paroxysmal patients. I do think there is a role for further large scale randomized trials which are ongoing and will happen in the future.

– Christine M. Albert, MD

Department of Medicine,
Brigham and Women’s Hospital, Boston

For more information:

Kowey P. LBCT II: Abstract 21811. Presented at: American Heart Association Scientific Sessions 2010; Nov. 13-17, 2010; Chicago.

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