Omega-3 Fatty acids: anti-arrhythmic, pro-arrhythmic, or both?

Area of Science:

• Cardiology
• Clinical Trials
• Nutritional Science

Background:

• Omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been investigated for their role in preventing cardiac arrhythmias.
• Previous reviews highlighted the need for further research following initial positive reports on EPA+DHA's effects.

Purpose of the Study:

• To review developments in the prevention of atrial fibrillation (AF) and ventricular arrhythmias after 2008.
• To assess the evidence for EPA+DHA in preventing sudden cardiac death (SCD) and improving outcomes in heart failure and post-myocardial infarction patients.
• To explore the utility of the omega-3 index for future intervention trials.

Main Methods:

• Medline searches and review of the author's personal database for pertinent publications.
• Analysis of data from clinical trials, electrophysiologic studies, and animal experiments.
• Evaluation of epidemiologic studies and the concept of the omega-3 index.

Main Results:

• Evidence suggests EPA+DHA may have a smaller-than-initially-expected effect on preventing postoperative AF, maintaining sinus rhythm, and new-onset AF.
• Trials on preventing ventricular arrhythmias in implantable cardioverter-defibrillator (ICD) carriers yielded unclear results.
• Epidemiologic studies support EPA+DHA's role in preventing SCD, but intervention trials have been inconclusive.
• EPA+DHA reduced mortality and rehospitalizations in heart failure patients but not SCD.
• No pro-arrhythmic effect of EPA+DHA has been observed in intervention studies.

Conclusions:

• Demonstrating the anti-arrhythmic effects of EPA+DHA in intervention trials remains challenging, despite supportive epidemiologic data.
• The omega-3 index offers a promising approach for future trials by identifying populations more likely to benefit from EPA+DHA supplementation.
• Targeting individuals with a low omega-3 index could enhance the effectiveness of intervention studies for endpoints like new-onset AF and SCD.