Cor triatriatum dexter, atrial septal defects, and pulmonary stenosis-a rare association.

Cor triatriatum dexter (CTD) is an extremely rare congenital anomaly in which the right atrium is divided into 2 chambers by a membrane. The estimated incidence of cor triatriatum has been reported as 0.1% of congenital cardiac malformations. The septation of the right atrium in the setting of CTD is the result of failed resorption of the right valve of the sinus venosus. This results in anterolateral and posteromedial portions of the divided right atrium. CTD can be diagnosed at any age, especially if it is incidentally discovered.