The sign of the vena cava: Echotomographic illustration of right cardiac insufficiency

In patients with hepatomegaly, evaluation of the vena cava was diagnostically valuable in differentiating between cardiac failure as a cause of the hepatomegaly and other causes. Studies were done using equipment with a mechanically moving probe to provide constant visualization of the vena cava. In normal patients, the vena cava is animated by a double motion from transmitted systolic pulsations and from the respiratory cycle. In normal patients, the vena cava collapses during expiration and in patients with right heart failure, the respiratory kinetics disappear and the inferior vena cava remains turgescent throughout the respiratory cycle.