Ebstein's anomaly of the left-sided atrioventricular (AV) valve in AV discordance.

Prosthetic valve replacement of the left-sided atrioventricular (AV) valve was performed in a patient with AV discordance and Ebstein's anomaly of the left-sided AV valve without other associated anomalies. An anatomical study of 22 specimens with AV discordance did not show a case with similar anatomy; 5 hearts had mild degrees of downward displacement of the attachment of the left-sided AV valve leaflets, with marked dysplastic changes and variable degrees of hypoplasia. The surgical implications are different according to the degree of downward displacement of the leaflets. This feature and the size of the annulus and the morphologically right ventricle should be considered in preoperative evaluation, along with the operative approach, possible presence of atrialization of the wall of the proximal chamber and the relation of the left AV valve to the conduction system. Preoperative diagnosis of the anomaly is possible by angiocardiography and other methods.