Echocardiographic evaluation of morphological and hemodynamic significance of giant left atrium. An important lesson.

In this issue of Circulation, Minagoe et all describe an interesting Doppler echocardiographic observation that blood flow velocity in the inferior vena cava (IVC) entrance into the right atrium is increased especially during inspiration in patients with a giant left atrium (GLA) and mitral stenosis. The increase in velocity was caused by the narrowed IVC orifice at its junction with the right atrium resulting from bulging of the atrial septum in these patients with GLA. Compared with the patients with lone atrial fibrillation or mitral stenosis without GLA, they had a smaller IVC orifice and higher flow velocity in the absence of severe tricuspid regurgitation. Two-dimensional and Doppler echocardiographic measurements were made from a right parasternal longitudinal plane, and pulsed-wave Doppler velocities in the IVC were recorded simultaneously with a respiratory tracing. In these patients with GLA, hepatomegaly by palpation was more frequent, and the authors concluded that a localized obstruction at the IVC orifice by GLA resulted in systemic venous congestion.