Prenatal Diagnosis and Outcome of Ebstein's Anomaly and Tricuspid Valve Dysplasia in Relation to Lung Hypoplasia

Although not all newborns with Ebstein's anomaly present with severe cardiomegaly in utero, some of them cannot live after birth because of the lung hypoplasia. To clarify the relationship between the intrauterine cardiomegaly and the outcome of the patients with Ebstein's anomaly or tricuspid valve dysplasia, we calculated the ratio of the area of the heart against the thorax (CTAR) in the transverse view of the thorax at the level of the cardiac four-chamber view in the fetal echocardiogram and compared it to the outcome. The study population consisted of four patients with Ebstein's anomaly and one patient with tricuspid valve dysplasia who were diagnosed in utero. The ranges obtained from 53 normal fetal cases were 20%± 8% (mean ± 2 SD) at below 20 week's gestation, 25%± 10% at the gestational age of 21 to 30 weeks, and 29%± 6.4% at the gestational age of 31 to 40 weeks. The CTARs of these five cases measured 81.6%, 51%, 55.2%, 47.5%, and 75.6%, respectively, and were abnormally higher than the normal value. Two fetuses died in utero with severe hydrops fetalis. Two fetuses whose cardiothoracic ratios by chest X ray were 100% died at twelve hours of life. One patient died at 110 days. The cross-sectional area of the thorax was smaller than the normal range in 3 (cases 1, 4, and 5) out of these 5 cases. Thus, we conclude that fetal Ebstein's anomaly and tricuspid valve dysplasia associated with massive tricuspid regurgitation with a large CTAR ratio (higher than 50%) and small thoracic cross-sectional area has a very poor prognosis bothprena-tally and neonatally. (ECHOCARDIOGRAPHY, Volume 11, May 1994)