Myocardial lipid metabolism in man during exercise (with special reference to coronary artery diseases)

Abstract

The exercise is useful both for the diagnosis and the treatment of coronary heart disease. In recent years, there are many articles treated with myocardial carbohydrate metabolism, but rarely with lipid metabolism during exercise. This paper reports a study of myocardial lipid metabolism during exercise in clinical cases. Materials and Methods Coronary sinus catheterization was performed by Bing's method in 19 clinical cases including 8 cases of coronary heart disease, 5 of hypertension, 4 of neurocirculatory asthenia and 2 others, after fasting for 6-18 hr. Patients were exercised for 15 minutes in the supine position on a bicycle ergometer with which 50 watts were loaded. Sampling both from coronary sinus and brachial artery was done at rest and during the 10th minutes of the period of exercise. Samples were analyzed in non-esterified fatty acid (NEFA) by Dole's method, in ketone bodies by Green-berg-Lester's modification, in triglyceride (TG) by Van Handel Zilversmidt's method. The catheter was kept patent by the slow infusion of the fluid which 1, 000 units heparine was added to 100 ml normal saline. The data of coronary blood flow, myocardial oxygen consumption, carbohydrate metabolism and left ventricular work, which obtained simultaneously by coraboraters, were used to the consideration of myocardial metabolism during exercise. Results and Comments 1. Arterial concentration and myocardial extraction of lipids ' a) NEFA; The arterial NEFA level showed a tendency to rise by influence of heparine infusion, but almost constant after two hours. At that time the exercise was performed. The arterial level showed decrease in 16 of 19 cases. Significant correlations were found between the arterial level and the myocardial extraction both at rest (r=0.05, n=19, p<0.02) and during exercise (r.67, n=19, p<0.01). The mean value of myocardial extraction was decreased, but of the usage was not so changed by exercise. b) Ketone bodies; There was a significant correlation (r=0.52, n=38, p<0.001) between the myocardial extraction and the arterial level through rest and exercise.