[Coronary reserve of the right ventricle evaluated by double dose T1-201 scintigraphy]

Thallium-201 double dose scintigraphy was applied to exercise to estimate the coronary blood flow reserve of the left and right ventricles and this was compared with the degree of coronary artery stenosis. As an index of coronary reserve we measured the rate of change of blood flow distribution (delta F) calculated from the change in myocardial radioactivity following thallium-201 injections, once at rest and once during exercise. With submaximal exercise the increases in delta F of the left ventricle were less in patients with ischemic heart disease than in the control subjects, and were less as the number of diseased coronary vessels increased. The increases of delta F of the right ventricle were less in patients with stenosis of the proximal portion of the right coronary artery than in patients without stenosis and in the control subjects. The more severe the stenosis of the proximal portion of the right coronary artery, the smaller the delta F of the right ventricle. These results indicate that evaluation of the delta F in the left and right ventricles is useful in estimating coronary artery stenosis.