Evaluation of use of left coronary artery inflow and O₂ content of coronary sinus blood as a measure of left ventricular metabolism

¹ Department of Cardiorespiratory Diseases, Walter Reed Army Institute of Research, Washington, D.C.

Experiments reported here show that the coronary sinus blood is derived almost entirely from the left coronary artery inflow and is not significantly contaminated with blood from other myocardial territories. The special cannula used for cannulating the coronary sinus permits drainage of all veins which empty into the coronary sinus. In consequence, the percentage of left coronary artery inflow recovered in the coronary sinus is high (usually 80–90%) and reasonably constant during changes in coronary perfusion pressure, aortic constriction, administration of epinephrine or norepinephrine, hemorrhage and reinfusion, induced ventricular fibrillation, and pulmonary artery constriction. The use of the arteriovenous oxygen difference between the arterial and coronary sinus blood in combination with left coronary artery inflow as a precise measure of left ventricular metabolism is validated under these experimental conditions.