Abstract
Recent many investigations have been demonstrated the changes of coronary circulation, general hemodynamics and myocardial metabolism during exercise and the relation between ECG changes. This report is one of these studies, but in which the bicycle loading is so intensive that the ischemic ECG changes appear in the patients with coronary diseases, and the balance of myocardial oxygen utilization to cardiac performance is studied at the same time. Methods and Subjects The systemic hemodynamic parameters were determined by right heart catheterization with direct Fick's method and coronary circulation was measured by coronary sinus catheterization with N20 desaturation technique and blood gas analyzing were made with Van Slyke-Neill method before and during exercise. Exercise was performed in the supine position with a bicycle ergometer for 15 minutes at a level of 50 watts. Thirty-three patients with circulatory diseases were subjected, consisting of 5 with neurocirculatory asthenia (NCA), 8 with hypertension (HT), 6 with hypertensive coronary failure (HTC), 7 with coronary heart disease (CHD) and 6 with than heart disease (HD). All subjects were divided also into 3 groups according to the electrocardiographic changes before and after the exercise test, namely, 16 cases of group 1 whose ECG has never shown ischemic finding before and after the Master's double two step test or ergometer, 14 cases of group 2 whose ECG has shown ischemic changes after the exercise tests or before exercise also and 3 cases of group 3 whose ECG has normalized partly in ischemic changes after exercise. Results Continuous measurement of oxygen and carbon dioxide in expired air of 17 patients with Metabolar made in Fukuda and Co. demonstrated that the bicycle ergometry at a rate of 50 watts demanded 4.4 Cal./min. and it takes about 66 calories for for 15 minutes, which is about 2.5 times of calories demanded for Master's double two step test. In spite of the observation, in 31 cases out of 33 patients, the electrocardiographic changes after bicycle ergometer evaluated by Master's criteria were quite same with the result of Master's double two step test which was done as the pretest. Characteristic findings of various circulatory diseases Heart rate increased in all groups equally during exercise. The cardiac index and stroke index were the lowest in CHD at rest, however the rate of increase during exercise was the highest. Systemic vascular resistance was the highest in CHD at rest. During exercise systemic vascular resistance decreased in all groups and the rate of decrease in CHD was significantly greater than that of NCA. Mean blood pressure increased slightly in HT and HTC during exercise. Left ventricular work was the highest in HT at rest and increased in all groups. Myocardial tension was the highest in HT and the lowest in CHD at rest and increased significantly in all groups during exercise. Coronary blood flow showed no significant difference among the diseases at rest.
