CORONARY CIRCULATION AND GASEOUS METABOLISM OF HUMAN HEART STUDIED BY CORONARY SINUS CATHETERIZATION

Abstract

Coronary sinus catheterization was performed in 112 human subjects, including thirty-three normal subjects, forty-six patients with cardiac failure, eleven patients with coronary sclerosis, six patients with hypertension, eight patients with anemia, seven patients with hyperthyroidism, and one patient with beri-beri. In these subjects myocardial gaseous metabolism has been investigated, while left ventricular coronary blood flow has been determined in forty-six of them by means of nitrous oxide methode.
1. In normal subjects the average oxygen extraction of left ventricular myocardium was 10.5 volumes per cent. The left ventricular coronary blood flow per 100 grams per minute and the left ventricular oxygen consumption per 100 grams per minute averaged 68.5cc and 7.1cc., respectively, and left ventricular myocardial efficiency averaged 29 per cent. The average myocardial RQ was 0.89.
2. In patients with cardiac failure due to valvular or hypertensive heart disease, the myocardial oxygen extraction were significantly increased. This was marked when failure was moderate or severe. The coronary blood flow was normal or slightly increased, resulting in the elevated myocardial oxygen consumption and low cardiac efficiency. In moderate or severe failure myocardial RQ was significantly reduced.
3. In patients with coronary sclerosis, most of whom had anginal pain on exertion, myocardial oxygen extraction was slightly but significantly increased, while the coronary blood flow was normal at rest, resulting in elevated myocardial oxygen consumption. Myocardial efficiency was slightly decreased but was within normal range.
4. In patients with essential hypertension both myocardial oxygen extraction and myocardial efficiency were normal. Further study is necessary, however, because only a few subjects were studied, including cases with slight hypertension.
5. In patients with anemia myocardial oxygen extraction was decreased but myocardial oxygen extraction coefficient (Cao₂-Cso₂)/Cao₂ was increased. Coronary blood flow was markedly increased, the ratio of coronary flow/cardiac output being higher than normal value. Myocardial efficiency was normal.
5. In patients with hyperthyroidism myocardial oxygen extraction was normal. Coronary blood flow was increased but the ratio of coronary flow/cardiac output was normal. Myocardial efficiency was normal.
7. After the administration of digitalis preparation (lanatoside-C or digicorin) in three patients with congestive failure coronary blood flow reduced about 10 per cent, resulting in the decreased left ventricular oxygen consumption and the elevation of cardiac efficiency.
8. The effect of exercise, hypoxia and hexamethonium bromide on myocardial gaseous metabolism and coronary hemodynamics were also demonstrated in healthy and diseased heart.