Effect of a peripheral arteriovenous fistula on coronary blood flow and cardiac oxygen metabolism

In anesthetized open-chest dogs, the mean blood pressure, cardiac output and coronary sinus flow were measured before and after opening of a unilateral or bilateral femoral arteriovenous fistulae. The opening of an A-V fistula was accompanied by a decrease in mean blood pressure and an increase in cardiac output and coronary sinus flow. Approximately 20 seconds after the fistula was opened, the coronary sinus flow established itself at a level independent of the per cent change in mean blood pressure and cardiac output. Opening of an arteriovenous fistula was also followed by a significant increase in myocardial oxygen consumption, work, and in most experiments by an increase in cardiac efficiency. During periods of opened-fistula the augmented myocardial oxygen consumption was accompanied by a spread of the arterial-coronary sinus oxygen difference.