Effect of Omega-3 Fatty Acids on Heart Rate Variability in Depressed Patients With Coronary Heart Disease

Objective: To determine whether omega-3 fatty acid (FA) increases the natural log of very low frequency (lnVLF) power, an index of heart rate variability (HRV), and reduces 24-hour heart rate (HR) in depressed patients with coronary heart disease (CHD). Low intake of omega-3 FAs is associated with depression and with low HRV, and all three are associated with an increased risk of death in patients with CHD. Methods: Thirty-six depressed patients with CHD randomized to receive 50 mg of sertraline and 2 g of omega-3/day, and 36 randomized to sertraline and a placebo, had 24-hour HRV measured at baseline and after 10 weeks of treatment. Results: There was a significant treatment × time interaction for covariate adjusted lnVLF (p = .009), for mean 24-hour HR (p = .03), and for 1-minute resting HR (p = .02). The interaction was not significant for three other measures of HRV. LnVLF did not change over time in the omega-3 arm but decreased in the placebo arm (p = .002), suggesting that omega-3 may have prevented or slowed deterioration in cardiac autonomic function. Conclusions: The effects of omega-3 FAs on lnVLF and HR, although modest, were detected after only 10 weeks of treatment with 2 g per day of omega-3. Whether a longer course of treatment or a higher dose of omega-3 would further decrease HR, improve other indices of HRV, or reduce mortality in depressed CHD patients should be investigated. CHD = coronary heart disease; FAs = fatty acids; EPA = eicosapentaenoic acid; DHA = docosahexaenoic acid; HRV = heart rate variability; VLF = very low frequency; BDI-II = Beck Depression Inventory; RBC = red blood cell; HR = heart rate; ULF = ultra low frequency; ECG = electrocardiogram; bpm = beats per minute; MI = myocardial infarction.