In Ebstein’s malformation, the tricuspid valve is abnormally developed. (The tricuspid valve is the gate between the right atrium, or upper chamber, and the right ventricle, or lower chamber, of the heart.) The abnormally developed valve may hinder blood flow into the right ventricle. It may also fail to close properly, allowing blood to leak backward (regurgitate) into the right atrium. Ebstein's anomaly may also be associated with pulmonary atresia, in which the pulmonary (lung) valve does not open or may be missing.
Progression and Possible Complications
Ebstein's anomaly has a very wide spectrum of clinical presentation, from an infant who is profoundly ill and cyanotic (bluish discoloration of the skin) at birth to a generally healthy child whose defect is discovered later in adulthood. The tricuspid valve’s malfunction can lead to enlargement of the heart’s right atrium. In addition, Ebstein's malformation is associated with a tendency for abnormal heart rhythm.
In severe cases, pressure in the right atrium may cause poorly oxygenated blood to cross through a small hole in the heart to the left atrium. When blood that is low in oxygen in the right atrium crosses into the left atrium, there is bluish discoloration of the red, oxygen-filled blood in the left atrium. The bluish-colored blood can cause bluish discoloration of the child's skin.
In cases of significant narrowing or obstruction (stenosis) or leakage (regurgitation) of the valve, surgery may be performed to reposition the opening of the valve toward a more normal location and relieve any obstruction. In addition, abnormal heart rhythm may be improved with medications or by a procedure that destroys the heart tissues that cause the abnormal heart rhythm. The procedure uses a catheter (a thin, flexible tube), threaded to the heart through the arteries, to send radiofrequency waves into the heart. The waves destroy the atrial tissue that is causing the abnormal rhythm.