Three-dimensional echocardiography in classification of Ebstein’s anomaly: a case report on agenesis of the tricuspid valve posterior leaflet

Abstract

Cardiologia CROATICA We present an echocardiographic evaluation of a 27-yearold young male patient who was referred to our institution after a loud systolic murmur was found during his occupational health check-up.. Besides the murmur, his physical exam, and results of his laboratory tests were normal. He has no significant complaints. His first 2D transthoracic echocardiogram (TTE) revealed severely dilated right ventricle (RV area greater than left ventricular area), volume overloaded and excentrically hypertrophied (wall thickness >6 mm), with severe tricuspid regurgitation (vena contracta 12 mm), large abundant sail-like anterior leaflet of the tricuspid valve (TV), apically displaced short septal leaflet (17 mm), and in the same time normal left ventricular systolic function and dimensions. These findings, especially apical displacement of septal leaflet indicate Ebstein’s anomaly. Ebstein’s anomaly is a rare congenital heart defect that occurs in only about <1% of congenital heart disease. In normal human hearts the apical displacement of the septal and posterior TV leaflets is <8 mm/m body surface area from the level of anterior mitral valve insertion. Differential diagnosis includes TV dysplasia, TV prolapse, TV endocarditis, and arrhythmogenic right ventricular cardiomyopathy, to name a few. With 2D TTE we were positive that this patient had some form of Ebstein’s anomaly, however we could not generate important information about valvular apparatus, such as morphology of the leaflets, the true origin of septal and posterior leaflets as well as precise coaptation. Those information are necessary in order to complete classification of TV pathology. Therefore we obtained 3D TTE and 3D TEE, and with multiplanar review mode and 3D reconstruction revealed complete agenesis of the posterior leaflet leaving almost unguarded tricuspid orifice with a large zone of lack of coaptation as the origin of severe tricuspid regurgitation. Subsequent 3D analysis also verified absence of complete posterior leaflet subvalvular apparatus, or in the context of embryological development, complete absence of posterior leaflet delamination. We used 2D echocardiography to study morphology and function of right ventricle, but 3D echocardiography provided additional important information regarding the morphology and orientation of TV and its apparatus. Only 3D TEE obtained agenesis of the posterior leaflet. According to parameters derived by 2D TTE and 3D TEE this patient was classified as type I Ebstein’s anomaly.