The circulatory adjustments in polycythemia vera

Abstract

1. 1. Measurements of cardiac output by the acetylene method, and of related circulatory functions, have been made on six patients suffering from polycythemia vera, and studies of the blood gases have been made on one of these patients, as well as on another subject suffering from polycythemia vera. 2. 2. At a time when the amount of hemoglobin and the count of the red blood cells were increased above normal, the arteriovenous oxygen difference was increased, the cardiac output per beat and the cardiac index were decreased, and the oxygen content of both the arterial and venous blood was increased. Left ventricular work, cardiac size, basal metabolic rate, blood pressure, and other functions of the circulation studied showed no consistent variation from normal. When reduction of the level of hemoglobin and red blood cells occurred as a result of therapy, the arteriovenous oxygen difference decreased and the cardiac index and output per beat increased and attained normal values when the red blood cells and hemoglobin reached normal levels. There was a linear relationship between quantity of hemoglobin and number of red blood cells on the one hand, and the cardiac output and the cardiac index on the other. These changes in circulation may be compensatory mechanisms which spare the heart part of the burden of pumping and increased total volume of circulating blood having an increased viscosity at a normal velocity.