Ebstein Syndrome

At a glance

This is a medical congenital condition that affects specifically the right side of the heart which is characterized by anomalies of the septum and the posterior leaflets of the tricuspid valve that are displaced toward the apex of the right ventricle (RV). The tricuspid valve anomalies are defined as deformation and improper placement between the right atrium and RV resulting in tricuspid valve complete insufficiency, that usually present in the neonatal period as a cyanotic heart disease but in the lesser condition can also remain asymptomatic throughout life.

Synonyms

Congenital Tricuspid Dysplasia; Ebstein Anomaly; Ebstein Malformation. (Do not confuse with Epstein Syndrome.)

History

First described in 1866 by the German physician Wilhelm Ebstein (b. November 1836 in Jauer, Prussian Silesia, d. October 1912). Dr Ebstein studied medicine in Breslau and Berlin and received his diploma from the latter University in 1859. He was named Professor of Medicine in 1874 at the University of Göttingen where he subsequently served as Director of the University Hospital and Dispensary from 1877 until completion of his career (JewishEncyclopedia.com).

Incidence

Accounts for approximately 0.5% of all congenital heart defects (1:20,000-50,000 live births). No sexual predilection has been reported. It is classified as a Critical Congenital Heart Defect which accounts for less than 1% of all congenital heart diseases and is believed to affect ≈1 in 200,000 live births.

Genetic inheritance

Sporadic in most cases. Lithium ingestion during pregnancy has been strongly related to Ebstein Syndrome. A few familial cases with a possible autosomal recessive transmission have been reported.

Pathophysiology

The age at presentation is dependent on the severity of tricuspid valve malformation and associated RV compromise. Patients with severe tricuspid valve malformation, hypoplastic RV, or RV outflow tract obstruction (RVOTO) are symptomatic shortly after birth, and cyanosis is common. While the annulus of the valve is in its normal position, the valve leaflets however are displaced downward into the RV in a way that parts of the RV becomes “atrialized” (ie, lies above the valve). The anterior and septal valve leaflets are affected the most and may be severely dysplastic, resulting in tricuspid regurgitation (TR). The distal ends of the valve leaflets may be fused, resulting in a variant degree of tricuspid stenosis. The anterior leaflet may obstruct the right ventricular outflow tract. Atrial septal defect (ASD) or enlarged patent foramen ovale (PFO) is present in almost all cases. Most often, the tricuspid lesion results in tricuspid insufficiency, but stenosis also is possible. Tricuspid regurgitation causes distention of the atrium and the atrialized ventricular portion, which is usually thin-walled with paradoxical movement during ventricular systole. Even distention may be seen during atrial systole. Because part of the RV is atrialized, the functional RV is ...