Echocardiography of the inferior vena cava in healthy subjects and in patients with cardiac disease.

Echocardiograms were recorded from the inferior vena cava (IVC) in 45 subjects: 10 normal subjects, 8 patients with cardiac volume overload due to anemia, 4 with severe right heart failure, 6 with significant tricuspid incompetence (TI), 7 with pericardial effusion (PE) and 10 with left-sided cardiac disease. The IVC was readily identified on the echo recordings made 1 to 2 cm below the junction of the hepatic veins. In normal subjects a double wave form was present on the IVC echogram for each beat: the waves corresponded to the "a' and "v' waves of the IVC pressure pulse tracing. The IVC diameter decreased on inspiration (P less than 0.01), particularly of the "x' descent (P less than 0.001). In patients with severe right heart dysfuction, the IVC was dilated (TI: P less than 0.02; PE: P less thaN 0.003; CMO: P less than 0.001), having lost its waveform and with diminished respiratory variation. There was, however, considerable overlap between the normal subjects and the different patient groups. In two of the patients with tamponade, the IVC did not empty upon inspiration, and pericardiocentesis was followed by a return of the waveform and normal respiratory changes. IVC dimensions were normal in patients with anemia and in those with left heart disease. The results of the study showed that the echogram may provide simple and useful measurements of IVC size and function.