Atrial fibrillation patients who took high dose Omega-3 fatty acid supplements did not have a lower risk of recurrence, researchers from the Lankenau Institute for Medical Research, USA, wrote in JAMA (Journal of the American Medical Association). The authors explain that some previous studies had suggested a possible link between Omega-3 oil intake and better atrial fibrillation outcomes. Their randomized trial, involving 600 participants found no reduction in atrial fibrillation recurrence among those taking high dose oils for six months. The study was also presented at the American Heart Association’s Annual Scientific Meeting 2010, Chicago.
The authors explain:
- “Atrial fibrillation (AF) is a highly prevalent disease that is responsible for reduced quality of life, costly hospitalizations, heart failure, stroke, and death. No current therapy, drug, device, or ablation [removal of tissue or cells] is uniformly effective, and several available therapies have the potential to cause harm. Consequently, useful alternatives are being sought. Limited data from small trials suggest omega-3 polyunsaturated fatty acids may provide a safe, effective treatment option for AF participants.”
The most common sources of Omega-3 fatty acids are oily fish, such as salmon, herring, mackerel, anchovies and sardines. Tuna is also a source, but in lesser amounts. Non animal sources include flaxseed, butternuts, hempseed, walnuts, pecan nuts, hazel nuts, Peter R. Kowey, M.D., and team carried out a randomized trial to find out how beneficial prescription omega-3 might be for patients with atrial fibrillation. They decided to give patients much higher doses than those used in previous studies. The primary outcome (main aim) was atrial fibrillation recurrence, and included 663 American outpatients, 542 of whom had been confirmed with sudden attacks (symptomatic paroxysmal) and 121 with persistent atrial fibrillation, but no substantial heart disease. They were enrolled from 2006 to July 2009 and followed-up until January 2010. They were given either 8-grams daily of prescription omega-3 or a placebo for the first week, then 4grams per day or a placebo from then on for 24 weeks.
At the end of 24-week period, the researchers found that:
- There were 129 cases of AF or abnormal rapid heartbeat (flutter) in the paroxysmal group on a placebo
- There were 135 cases of AF or flutter in the paroxysmal group on the omega-3
- There were 18 symptomatic AF or flutter events among the persistent AF patients on the placebo
- There were 32 symptomatic AF or flutter events among the persistent AF patients on the omega-3
- There were a total (both groups) of 147 events in the placebo group compared to 167 in the omega-3 groups
No statistical difference was found between first recurrence of atrial fibrillation or flutter in the persistent group and both groups combined, the authors wrote. Adverse events caused 12 omega-3 patients and 16 placebo patients to discontinue treatment.
The authors wrote:
- “In this population of patients with symptomatic paroxysmal AF or persistent AF, and no evidence of substantial structural heart disease, prescription omega-3 did not show evidence of reducing the recurrence of symptomatic atrial fibrillation.”
When commenting on what factors might have impacted on previous study findings, the authors wrote:
- “Either the positive results reported in some trials represent a chance effect of small sample sizes or the differences are real. If the latter, there are several possibilities, including differences in the study populations, in population-specific AF mechanisms, in dosing regimens and product formulations, or in concomitant therapies. In our study, nearly half the events occurred during the first 2 weeks of follow-up, suggesting that fish oil may not have rapid effects, even with high-loading doses.”
JAMA. Published online November 15, 2010. doi:10.1001/jama.2010.1735
Written by Christian Nordqvist