Findings from a new study show, compared to placebo, treatment with high-dose prescription omega-3 fatty acids did not reduce the recurrence of symptomatic Atrial Fibrillation (AF) among patients with symptomatic paroxysmal AF or persistent AF who have no evidence of substantial structural heart disease.

This was a six-month, multi-centre, randomized double-blind, placebo-controlled, parallel-group trial sponsored and funded by GlaxoSmithKline. It examined the efficacy and safety of prescription omega-3 fatty acids (Lovaza, omega-3-acid ethyl esters) for the prevention of recurrent symptomatic atrial fibrillation.

Lovaza is a prescription medication made from omega-3 fish oil indicated as an adjunct to diet, to reduce triglyceride levels in adult patients with severe (= 500 mg/dL) hypertriglyceridemia. The effect of Lovaza on cardiovascular mortality and morbidity in patients with elevated triglycerides has not been determined. It is not indicated for the treatment or prevention of recurrent symptomatic AF. GSK has full commercial rights for Lovaza in the US.

The study showed no benefit in reducing the recurrence of symptomatic AF in patient groups treated with high-dose, prescription omega-3 fatty acids and placebo. In both the pre-specified original analysis and the analysis of an independent statistician, the rate of recurrence to AF or flutter was higher in the Lovaza arm compared to placebo. The incidence of treatment-emergent adverse events was similar between the two treatment groups. Five per cent of patients on placebo and 4% of patients taking prescription omega-3 discontinued the study medication due to adverse events.

Previous clinical trials of omega-3 fish oils used in AF have yielded mixed results. The study authors reviewed several factors which might contribute to the differences between their findings and those of other studies, such as differences in study populations, dosing regimens, product formulations or use of concomitant therapies.

“Based on its size and scientific rigour, this study adds significantly to the body of knowledge of the role and potential effects of high-dose prescription omega-3 fatty acids in AF,” said Dr. Murray Stewart, clinical vice president of cardiovascular and metabolic medicines development at GSK. “We will continue to review the data from this study in the context of other AF studies with Lovaza and other omega-3 fatty acids; however, in this patient population there was clearly no benefit from Lovaza.”

Atrial fibrillation is the most common type of arrhythmia, a problem with the rate or rhythm of the heartbeat. This leads to poor blood flow. AF is characterized by an irregular and often rapid heart rate. People with AF may or may not feel symptoms, which include heart palpitations, shortness of breath and weakness. It may occur rarely or occasionally, or it may become persistent.

According to the American Heart Association, AF is a disorder found in about 2.2 million Americans. AF is related to age and the risk increases the older people get. Men and women are equally susceptible to the disease. Other risk factors include heart disease, high blood pressure, other chronic conditions such as thyroid disease, drinking alcohol and family history.