is a congenital heart defect
in which the opening of the tricuspid valve
is displaced towards the apex of the right ventricle
of the heart
The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. There is subsequent atrialization of a portion of the morphologic right ventricle (which is then contiguous with the right atrium). This causes the right atrium to be large and the anatomic right ventricle to be small in size.
There may be an increased risk of this abnormality in infants of women taking lithium
during the first trimester of pregnancy, and in those with Wolff-Parkinson-White syndrome
Ebstein's anomaly was named after Wilhelm Ebstein
While Ebstein's anomaly is defined as the congenital displacement of the tricuspid valve towards the apex of the right ventricle, it is often associated with other abnormalities.
Typically, there are anatomic abnormalities of the tricuspid valve, with enlargement of the anterior leaflet of the valve.
About 50% of individuals with Ebstein's anomaly have an associated shunt between the right and left atria, either an atrial septal defect or a patent foramen ovale.
About 50% of individuals with Ebstein's anomaly have evidence of Wolff-Parkinson-White syndrome
, secondary to the atrialized right ventricular tissue.
Ebstein's cardiophysiology typically presents as an atrioventricular reentrant tachycardia with associated preexcitation. In the acute setting with EKG evidence of preexcitation, the preferred pharmacological treatment agents include procainamide
since these medications slow conduction in the accessory pathway causing the tachycardia and should be administered before considering electrical cardioversion