Cor triatriatum dexter: two-dimensional echocardiographic diagnosis.

Cor triatriatum dexter is a malformation resulting from lack of normal regression of the embryonic right valve of the sinus venosus. In this situation, the right atrium is divided by a membrane into two chambers. Two-dimensional echocardiography was used in the antemortem diagnosis of this rare cardiac anomaly in a neonate. Associated cardiac lesions were also documented. The patient died, and findings were verified at autopsy.