A cardiovascular cause of hematemesis.

Cor triatriatum is a rare congenital heart defect in which a fibromuscular membrane forms an anomalous septum within the left atrium, dividing it into a posterosuperior higher pressure chamber and an anteroinferior anatomically true left atrium. Typically, in cor triatriatum, all four pulmonary veins enter into this accessory chamber, we present an unusual variant of cor triatriatum, in which only the right sided pulmonary veins were involved.