A new radiographic method for cardiac output and cardiac shunt determination in vivo.

The present paper describes a new method for the measurement of cardiac output (CO) and cardiac shunt (CS). The CO method is based on the accurate determination of the concentration of the indicator in large vessels. For the measurement of the left to right shunting volumes, a double tracer technique is used by which radioactively labeled transferrin or erythrocytes are applied together with radioactively labelled human-serum-albumin (HSA) microspheres. The results obtained using these methods were compared with the data obtained by invasive methods. High correlation of both sets of data suggests that the proposed methods might provide an excellent extension of noninvasive procedures in the first months of a childs life.