Cor triatriatum dexter: unusual features in utero and after birth.

Cor triatriatum dexter is a rare congenital anomaly, caused by the persistence of the right valve of the sinus venosus, which divides the right atrium into two chambers and its diagnosis is rather difficult, due to the features often mimicking Ebstein's anomaly. We describe a case followed from the foetal age for a relative right ventricular hypoplasia and suspicious pulmonary stenosis and diagnosed after birth to have cor triatriatum dexter with an obstructing membrane in the right atrium, needing surgical correction, done successfully.