Ebstein's Anomaly: Echocardiographic and Clinical Features in the Fetus

Background:Ebstein's anomaly is characterized by various degrees of apical displacement of the proximal attachment of the tricuspid valve. The disease has an extremely variable course in presenting itself. Therefore, we examined the morphologic and clinical features of Ebstein's anomaly as presented in the fetus to define the factors that determine its outcome. Methods:We reviewed the history and echocardiographic studies of 10 fetuses(mean gestational age 28.0 weeks diagnosed in utero with Ebstein's anomaly. The reason for referral was cardiomegaly on routine obstetric scanning in 5 cases, fetal arrhythmia in 3 cases, small main pulmonary artery in 3 cases, vessel view in 1, and twin pregnancy complicated by polyhydramniosis in 1. Results:Of the 10 cases, pregnancy was terminated after diagnosis in 5, 2 cases were carried to term, and 1 case was at 34 weeks of gestation. We were unable to follow-up 2 cases. There were no intrauterine deaths and no misdiagnoses. Massive cardiomegaly and severe tricuspid regurgitation were detected in 7 cases; mild cases were detected in two, and one was nearly normal. Associated cardiac lesions included pulmonary artresia in 4 cases, pulmonary stenosis in 3, and pulmonary hypoplasia in 1. The cases with right ventricular outflow tract(RVOT obstruction showed a tendency to develop more cardiomegaly and tricuspid regurgitation than with normal RVOT. There was no abnormality in other organ systems and karyotyping. Conclusion:Although increased cardiothoracic ratio and associated lesions of the right ven- ricular outflow tract contribute to the poor outcome in the prenatally detected cases, the absence of