Live/real time three-dimensional transthoracic echocardiographic assessment of Ebstein's anomaly.

We describe our experience in using live/real time three-dimensional transthoracic echocardiography (3D TTE) in the assessment of five adult patients with Ebstein's anomaly. The technique was found useful in assessing the distribution and extent of tethering of each of the three leaflets of the tricuspid valve (TV) to the underlying right ventricular walls and the ventricular septum. The characteristic bubble-like appearance resulting from bulging of the non-tethered areas of the TV leaflets was also well visualized in three dimensions and their size measured. Thus, an estimate of the nontethered or free segments of all three leaflets of the TV could be obtained using this technique. This has important implications when considering these patients for surgical repair of the TV. Visualization of all three leaflets of the TV and their extent of tethering by 3D TTE also made it easier to identify the boundaries of the functioning right ventricular chamber potentially providing a more reliable assessment of its volumes and ejection fraction. Cropping of color Doppler 3D TTE data sets provided en face viewing of the TV regurgitation vena contracta permitting accurate assessment of its shape and size. This has the potential to provide a more accurate quantitative estimation of TV regurgitation severity as compared to two-dimensional color Doppler. In conclusion, live/real time 3D TTE appears useful in supplementing two-dimensional echocardiography in more comprehensively assessing the morphologic features of Ebstein's anomaly.