Analysis of the Radiocardiogram in Heart Failure

Abstract

A scintillation counter permits the use of very low doses of I 131 -albumin in the recording of radiocardiograms. In the presence of mild heart failure there is a distinct widening of the interval between the humps derived from the right and left heart. Application of the principle of three-compartment serial dilution suggests that this prolongation may be due in large part to reduced cardiac output; however, cardiac dilatation may contribute significantly. Although radiocardiographic tracings represent time concentration curves, wide angle counting over the heart does not permit a reliable direct estimate of cardiac output. The chief source of error lies in the variable contribution of surrounding extracardiac tissue to the total activity which is recorded.