Persistent valve of systemic venous sinus: a cause of neonatal cyanosis.

Incomplete involution of valve of systemic venous sinus can present across a spectrum of anatomical lesions ranging from eustachian valve to division of right atrium (cor triatriatum dexter) with overlapping features. We present the case of a neonate presenting with cyanosis, having persistent valve of systemic venous sinus with anatomical details of the redundant tissue in right atrium suggesting an intermediate form between Chiari network and division of right atrium.