Research on the human pulmonary circulation by means of cardiac catheterization and radioactive tracers

In two patients with atrial septal defect it was possible to study with two catheters, one in the pulmonary artery and another one at the entrance of the pulmonary veins, the distribution curve P(t) of the pulmonary circulation times and its mean value. With this purpose albumin I/sup 131/ was injected into the pulmonary artery and blood was sampled at the entrance of the pulmonary veins with simultaneous registration of the radiocardiography. The mean value of pulmonary circulation time was between 2.6 and 2.7 seconds. It was shown that the P(t) curve can be derived, with good approximation, from the radiocardiography obtained by injecting the tracer into the right ventricle. (auth)