右室心筋酸素代謝に関する実験的検討:左室心筋酸素代謝との比較

A comparison of blood flow and myocardial oxygen consumption (MVO2) in the right and left ventricles was made in 24 open-chest dogs. Simultaneous measurements were made of the left anterior descending (LAD) and right coronary arterial (RC) blood flow, and of O(2) saturation in the coronary sinus and in from one to four anterior cardiac veins. Blood flow was greater in the LAD than in the RC, 87.4±36.0 and 46±22.0 ml/min/100g, respectively. The O(2) extraction was 51.3±11.0 in the anterior cardiac veins and 60.0±6.3% in the coronary sinus. The mean MVO(2) was greater for the left than for the right ventricles, 8.6±3.3 vs. 4.0±2.1 ml/min/100g. An increase in LAD flow without an increase in O(2) extraction accounted for the enhancement of MVO(2) of the left ventricle induced by pacing, isoproterenol or methoxamine. In contrast, pacing, isoproterenol or constriction of the pulmonary artery increased MVO(2) of the right ventricle with an increase in both O(2) extraction and right coronary blood flow. These results indicate that the right coronary arterial blood flow is lower per unit weight of tissue and is less dependent on MVO(2) than is LAD blood flow.