Estimation of the rates of uptake of Rb 86 by the heart, liver and skeletal muscle of man with and without cardiac disease

Abstract

The rate of uptake of Rb 86 from the blood by the myocardium was estimated in a group of subjects with coronary arteriosclerosis and compared to the rate in controls and in subjects with other types of heart disease. These studies were prompted by experiments in dogs which showed that the amount of coronary blood flow is probably an important determinant of the rate of uptake of Rb 86. Two-thirds of the Rb 86 in arterial plasma is removed during one circulation through the dog's heart. The rate of Rb 86 uptake is increased by l-norepinephrine and decreased by pitressin, changes which are in the same direction as the known effects of these drugs on coronary blood flow. The rate of uptake of Rb 86 would also probably be affected by differences in the kinetics of potassium within the myocadrium, since rubidium and potassium are very similar in their biological and chemical properties. The differences in rate of uptake of Rb 86 by the myocardium in different dogs could be estimated within 20 per cent by using a scintillation counter placed over the precordium of the intact animal. This report summarizes the findings in 35 human subjects studied by methods similar to those used previously in dogs.