Objective: Our aim was to elucidate the morphologic spectrum of Ebstein's malformation of the tricuspid valve with regard to diagnosis and the feasibility of surgical repair, in the light of the currently favored reconstructive techniques.
Methods: We examined 23 autopsied hearts. Taking the displacement of the septal and mural leaflets of the abnormal tricuspid valve as our diagnostic criterion, we focused subsequently on the location of the distorted valvular orifice and the attachment and formation of the anterosuperior leaflet. We also assessed the dimensions of the components of the right ventricle relative to the plane of the displaced valvular orifice.
Results: In all hearts, the septal and mural leaflets were hinged at various points within the inlet of the right ventricle. In many cases, however, these leaflets were virtually absent. The plane of the effective tricuspid valvular orifice was displaced anterosuperiorly to varying degrees. In the most severe forms, the valvular mechanism took the form of a 1-leaflet valve. The length of the functional right ventricle when compared with the left ventricle ranged proportionally from 0.6 to 1. 1 (mean, 0.9).
Conclusions: Ebstein's malformation is much more than simple "downward displacement" of the leaflets. In essence, the valvular orifice is formed within the ventricular cavity at the junction of the atrialized inlet and functional ventricular components. When surgical intervention becomes necessary, it is essential to make a detailed assessment of both valvular and ventricular abnormalities.