Direct demonstration of an air-fluid interface by two-dimensional echocardiography: a new diagnostic sign of hydropneumopericardium.

Hydropneumopericardium is an uncommon condition that requires prompt diagnosis and treatment if hemodynamic compromise is present. Chest roentgenography, computerized tomography, and echocardiography provide important information for the diagnosis. In this article a new distinctive echocardiographic sign of hydropneumopericardium is described: the direct demonstration of the air-fluid interface in the long-axis precordial view.