Ebstein's anomaly - antenatal ultrasound
Ebstein’s anomaly is one of rare congenital cardiac anomalies accounting for around 0.2-0.5 % of all cardiac anomalies 1,2 . The primary anomaly is an abnormal inferior (apical) displacement of the tricuspid valve leaflets, mainly the septal and the posterior leaflets, which leads to significant shortening of the functional right ventricle 2-4. The valve is not only abnormal in position but also abnormal in morphology and is usually thickened and incompetent leading to tricuspid regurgitation and to a lesser extent tricuspid stenosis. The part of the right ventricle above the anomaly is referred to as atrialized right ventricle. The atrialized right ventricle and the tricuspid annulus are often significantly dilated. Right atrium is usually hugely dilated. ASD is almost always present. A number of other associated cardiac defects are also present including pulmonary hypoplasia/ atresia, aortic and mitral valve abnormalities and VSD 2,5.
The prognosis is poor and fetal hydrops followed by demise usually results in majority of cases 6. The neonatal chest radiograph shows markedly enlarged box shaped heart. Cyanosis and cardiac failure are usually the presenting features in neonates and infants 7. Older children may present as cardiac murmurs. Few mild cases may remain asymptomatic till adulthood and present as arrythmias 7.
Based on the prognosis of the case and being able to detect the anomaly early (18 weeks) medical termination of pregnancy was offered to the mother.