Cor Triatriatum With Partial Anomalous Pulmonary Venous Return: A Rare Case of Parallel Obstruction and Successful Staged Treatment

Cor triatriatum sinister is an uncommon congenital cardiac defect that has rarely been described in association with left-sided partial anomalous pulmonary venous return. We present a case of such rare anatomy with multilevel obstruction that presented in infancy as cardiogenic shock. The patient underwent staged treatment with extracorporeal membrane oxygenation stabilization, catheter-based balloon dilatation of the cor triatriatum and atrial septostomy, followed by definitive surgical repair, with excellent result.