Effect of Coronary Blood Flow on Radioisotope Dilution Curves Measured by Precordial Scintillation Detection

Abstract

Two series of animal experiments are reported. In the first of these, the disappearance rates of intravenously injected radioactive boluses were monitored over the heart and from a peripheral artery. The disappearance rate over the heart was shown to be slower than in the artery. In a second series of experiments in which injection was made into the left ventricle or into a coronary artery while sampling from the right side of the heart, it was shown that the coronary transit time was several times longer than the left ventricular transit time. The prolonged presence of the radioactivity in the coronary vascular bed accounts for the difference in the heart and arterial disappearance slopes. A ratio of these two slopes may provide an index of coronary blood flow.