Effects of free fatty acids on experimentally infarcted myocardium.

The effects of serum free fatty acid (FFA) on the experimentally infarcted heart were studied from the standpoints of cardiac dynamics, infarct size and mitochondrial function in comparison with the effects of glucose. The left anterior descending coronary artery of the dog was ligated for 60min. Before and during coronary ligation, palmitic acid, oleic acid, saline, or glucose was infused intravenously for 30min. According to the degree of elevation of epicardial ST-segment, the left ventricular myocardium was divided into "infarcted", "peri-infarcted", and "non-infarcted" areas. After 60min of coronary ligation mitochondria were isolated from each area, and their respiration was measured polarographically. In FFA treated dogs, cardiac contractility (indicated by isometric time tension index) and respiratory control index of the infarcted area were deteriorated. The changes of cardiac contractility and mitochondria) function were more remarkable in oleic acid infusion than in palmitic acid infusion. However, FFA infusion did not affect the extent of injured area. In summary, it is considered that high level of serum FFA especially oleic acid had unfavorable effects on the ischemic heart in contrast with glucose treated dogs in which distribution of oxidative phosphorylation and impairment of contractility were mild but the extention of the infarct size was not prevented.