Heart Disease Health Center

Fish Oil Prevents Deadly Irregular Heartbeats

April 30, 2004 -- A fish oil infusion may help prevent a potentially deadly quickening of the heart (arrhythmia) in people at risk for sudden cardiac death, a new study shows.

Although more studies will be needed to confirm these results, researchers say these early findings may help explain how fish oil appears to reduce the risk of sudden cardiac death in certain people.

Several studies have shown that a diet rich in fatty fish or use of fish oil supplements containing omega-3 fatty acids can reduce the risk of sudden cardiac death. But until now researchers have been unable to provide direct evidence of how fish oils may work to prevent the irregular heartbeats, known as arrhythmias, often responsible for triggering sudden cardiac death.

Fish Oil Protects Heart

In the study, published in this week's issue of The Lancet, researchers examined the effects of fish oil in 10 people at high risk for sudden cardiac death. The patients all had implanted defibrillators (to shock their hearts out of a dangerous arrhythmia if needed) and a history of ventricular tachycardia, or a dangerous quickening of the heartbeat.

In the study, researchers injected the patients with an infusion of omega-3 fatty acids and then tried to induce an episode of ventricular tachycardia. At the start of the study, researchers were able to induce this irregular heartbeat in seven out of 10 of the participants.

After the fish oil infusion was delivered, researchers were only able to induce the arrhythmia in two of the patients, and the second was only after a more aggressive attempt. In the remaining five, the fish oil appeared to prevent the irregularity.

Although researchers say this was a small study designed to look at the safety of using fish oil infusions in protecting against ventricular arrhythmias, the results show that fish oil may have anti-arrhythmic effects.

In a commentary that accompanies the study, Christine Albert, MD, of Brigham and Women's Hospital in Boston, says these results are only preliminary. But combined with previous research, they provide a possible mechanism that explains the selective benefits of fish oil in reducing sudden cardiac death found in other studies.

"If these and other trials confirm the anti-arrhythmic properties of these [omega-3 acids], fish oil may become a less toxic and more appetizing alternative to traditional anti-arrhythmic," writes Albert.