Abstract
Comparative coronary sinus flow rates and oxygen AV difference were studied in dogs undergoing left heart bypass with left atrial or left ventricular drainage at similar maximum obtainable flow rates. Left atrial bypass decreased the coronary sinus flow rates and oxygen consumption when compared with control values. These values were further decreased when left ventricular bypass was used. The oxygen consumption data were highly significant and give further evidence of increased effectiveness of complete bypass of the left ventricle in myocardial support systems.