The value of contrast cross-sectional echocardiography in the diagnosis of tricuspid regurgitation.

Reflux of contrast into the inferior vena cava and hepatic veins during held expiration was studied in 70 subjects using subxiphoid 2D echocardiography. Venous reflux of contrast occurred in 7/19 normal subjects (group 1), 13/17 patients with definite or probable tricuspid regurgitation (group 2), 10/13 patients with congestive cardiac failure (group 3) and 10/21 patients with miscellaneous cardiac conditions unlikely to be associated with tricuspid regurgitation (group 4). There were 30 patients with no appearance of microbubbles in the inferior vena cava and hepatic veins on suspended expiration: 10 of these had reflux of contrast when breathing was restarted. Of the 17 patients with atrial fibrillation, 14 showed reflux, but there were 3 patients with no reflux. We conclude that the appearance of contrast in the IVC and hepatic veins may be found in many subjects in whom tricuspid regurgitation is unlikely on clinical grounds, even when recordings are taken in held expiration. Atrial fibrillation alone does not necessarily cause venous reflux of contrast. Demonstration of simple venous reflux of contrast by 2D echocardiography is too non-specific for routine use in the detection of tricuspid regurgitation.