Fish Oil and Arrhythmias, Cardiac Arrest

ADELAIDE, AUSTRALIA. There is ample evidence that a high fish consumption and oral supplementation with fish oils (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) are highly protective against cardiac arrest (sudden cardiac death – SCD), a condition responsible for about 50% of all cardiac-related deaths. It is generally believed that the protective effect of fish oils is due to their ability to prevent fatal ventricular tachycardias. Cardiologists at the Royal Adelaide Hospital now provide further proof that the SCD-preventive effects of fish oils are indeed related to their antiarrhythmic effect in patients with ischemic heart disease.

Fish Oils and Heart Disease

Their clinical trial included 26 patients with coronary artery disease, which is one of the most common forms of heart disease, undergoing defibrillator implantation. All patients had demonstrated in a baseline electrophysiologic study that monomorphic ventricular tachycardia (VT) could be induced by pacing at the right ventricular apex. Twelve of the patients were assigned to supplement with 3 grams/day of fish oil providing 540 mg/day of EPA and 360 mg/day of DHA. The remaining 14 patients served as a control group. Following a 6-week supplementation period a repeat electrophysiologic study was performed. In this study VT could no longer be induced in 42% of those in the fish oil group versus 7% of those in the control group; another 42% in the fish oil group required more aggressive stimulation to produce VT, and 8% required less stimulation. Corresponding percentages in the control group were 36% and 21%.

The Antiarrhythmic Effect of Fish Oils

The researchers conclude that fish oil supplementation significantly reduces the inducibility of VT, thus suggesting that fish oils do indeed have an antiarrhythmic effect in patients with ischemic heart disease.
Metcalf, RG, et al. Effect of dietary n-3 polyunsaturated fatty acids on the inducibility of ventricular tachycardia in patients with ischemic cardiomyopathy. American Journal of Cardiology, Vol. 101, 2008, pp. 758-61

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