**3. Pathologic anatomy**

Carpentier et al. described the characteristic features of this disorder that are relevant to surgical management [11].


In addition to the leaflet abnormalities there is a variable degree of ventricular myocardial dysfunction. Morphometric histopathologic studies have demonstrated that there is an absolute decrease in the number of myocardial fibers in addition to thinning of the wall of the dilated RV in EA [12].

Carpentier et al. also described four grades of Ebstein's anomaly [11].

*Type A*: The anterior leaflet has normal morphology and the RV is adequate.

*Type B*: The anterior leaflet has abnormal chordae but normal mobility. The RV is reduced in volume but adequate.

*Type C*: The anterior leaflet is restricted in movement. The RV is small with a large atrialized component.

*Type D*: Also called 'tricuspide sac' as the leaflets form a complete sac of fibrous tissue adherent to the RV. The only functional part of the RV is the infundibulum.
