[Utility of echo enhancers in the study of pulmonary circulation time]

Pulmonary circulation time (PCT) varies under different clinical conditions. To evaluate the PCT, the persistence of contrast in both ventricles and the digital arterial saturation of oxygen with peripheral intravenous injection of microbubbles, were examined 14 patients. Groups: I normals, II left ventricular hypertrophy (EF > 50%), III with mitral stenosis and IV in congestive heart failure. In seven patients, isosorbide S/L was administered after the first injection. The transpulmonary transit in beats was 7.3 in normals, and larger in the others. The persistence of echo contrast in right chambers was 31 beats in group I, and larger in the other groups. In left chambers it was 20.6 beats in group I, and larger in others. There were no alterations with regards to peripheral arterial saturation of oxygen. AII patients with isosorbide presented shorter PCT and persistence of contrast in right chambers.

There are differences in PCT among normals, patients with mitral stenosis and those with congestive heart failure. Prolonged persistence contrast in right chambers indicates abnormally slow transpulmonary transit. Patients with congestive heart failure and ventricular damage, have longer persistence of echo contrast. PCT studied with contrast is an easy means of evaluating some aspects of pulmonary circulation.