Figure 1.

Effect of omega-3 polyunsaturated fatty acids (n− 3 PUFAs) on the heart rate and heart rate variability response to acute myocardial ischemia (2 min left circumflex coronary artery occlusion) in dogs susceptible to ventricular fibrillation. Dietary n−3 PUFA, but not the placebo, produced a significant downward shift of the heart rate (HR) response that was accompanied by an upward shift in the high frequency (HF) component of the R–R interval variability (vagal tone index 0.24–1.04 Hz; i.e., significant pre–post-treatment effect: HR, P < 0.02; HF, P < 0.03). Despite the shifts in the curves, the absolute change in these variables induced by the coronary artery occlusion was not altered before or after the treatment (i.e., there were no significant pre–post-treatment × coronary occlusion interactions: HR P = 0.57; HF, P = 0.47). Placebo (n = 9) or n−3 PUFA (1–4 g/day, n = 22), pre = before treatment began, post = after 3 months of treatment.