title: (N-3) fatty acids do not affect electrocardiographic characteristics of healthy men and women.
abstract: (n-3) Fatty acids may reduce the risk of sudden death by preventing life-threatening cardiac arrhythmia. A standard electrocardiogram (ECG) may be used to detect clues as to the mechanism by which (n-3) fatty acids affect the electrophysiology of the heart. An earlier study showed that (n-3) fatty acids decreased the duration of the heart-rate corrected QT interval (QTc) in dogs. However, effects of (n-3) fatty acids on the standard ECG of humans have not been reported. Therefore, we investigated the effect of (n-3) fatty acids on QTc, QRS duration, apex-to-end-T duration, T-loop morphology and spatial QRS-T angle in apparently healthy men and women aged 50 to 70 y. Subjects (n = 42/group) received either capsules providing 1.5 g (n-3) fatty acids daily or placebo for 12 wk. ECG were recorded before and after intervention. None of the ECG characteristics were affected by (n-3) fatty acids. The QTc decreased by 0.8 ms or 0.2% (95% confidence interval, -6.1 to 4.4 ms) in subjects that consumed (n-3) fatty acids compared with the placebo group. These results do not support the hypothesis that (n-3) fatty acids prevent arrhythmia through electrophysiologic effects on heart cell membranes. However, an effect on the ECG in more susceptible populations can not be excluded.
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D004311:Double-Blind Method; D004562:Electrocardiography / Q000187:drug effects*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000737:chemistry; D006329:Heart Conduction System / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D010919:Placebos