Ebstein's anomaly--an autopsy study of 28 cases.

Twenty eight autopsy specimens of Ebstein's anomaly were studied in order to evaluate the morphologic features of the abnormal tricuspid valve. All cases showed marked dilatation of the original tricuspid annulus, a normally positioned anterior leaflet and variable downward displacement of the posterior and septal leaflets. Sixteen cases showed a very large anterior leaflet. All three leaflets showed dysplastic features and a wide range of anatomic abnormalities in the valve and valve apparatus. A thin walled atrialised right ventricle was present in nine cases. Associated cardiac anomalies were seen in 21 cases, the commonest being an atrial septal defect (17 cases).