Abstract
Many authors have reported the changes of myocardial lactate metabolism during angina or coronary insufficiency induced by exercise or atrial pacing. However, a precise correlation of myocardial carbohydrate metabolism with electrocardiographic changes during exercise has not been studied for various circulatory diseases. The purpose of this paper is to clearify the aspect of myocardial carbohydrate metabolism and its role for the myocardial energy source under the condition in which the exercise load is so intensive that the appearance of ischemic ECG changes can detect the coronary insufficiency. Methods and Subjects: The arterial blood taken from brachial artery and coronary sinus sampled by coronary sinus catheter was analised. The sampling was carried out three times, immediately after the insertion of coronary sinus catheter, after keeping rest before exercise and ten minutes after starting exercise. Blood glucose was determined by glucose oxidase method, lactate by hydroxybiphenyl method according to Barker and Summerson and pyruvate by dinitrophenylhydrazine method according to Friedemann and Haugen. Coronary blood flow was measured by the nitrous oxide method. Exercise was performed in the supine position at a level of fifty watts for fifteen minutes with bicycle ergometer. Thirty six patients with circulatory diseaes who were fasting for six to eighteen hours were studied, consisting of 5 with neurocirculatory asthenia (NCA), 8 with hypertension without coronary insufficiency (HT), 7 with hypertensive coronary failure (HTC), 7 with normotensive coronary heart disease (CHD) and 9 with the other heart diseases (HD) such as valvular disease etc. All subjects were also classified into 3 groups according to the electrocardiographic changes before and after the exercise test, namely, 17 cases of the negative test group before and after Master's double two-step test or bicycle ergometry, 16 cases of the positive test group whose ECG showed ischemic changes after the exercise tests or also before exercise and 3 cases of the improved group whose ischemic ECG changes were partly normalized after exercise.
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