Cor Triatriatum Sinister With a Decompressing Levoatriocardinal Vein: A Rare Association.

Levoatriocardinal vein has rarely been described with cor triatriatum. We report a case of a newborn with respiratory distress who was found to have cor triatriatum sinister with a decompressing levoatriocardinal vein on transthoracic echocardiography. The pulmonary venous confluence received all pulmonary veins and drained to the proximal left atrial chamber through significant communication. Moreover, the cor triatriatum membrane separated the left atrial body into proximal and distal left atrial chambers with a restrictive opening in the membrane, causing severe flow limitation to the cardiac output, severe pulmonary arterial hypertension, and significant right ventricular dilatation. In addition, a sizeable levoatriocardinal vein decompressed the pulmonary venous confluence drained superiorly to the left innominate vein. She had a successful surgical repair by resectioning the cor triatriatum membrane and ligating the levoatriocardinal vein. The patient had improved pulmonary arterial pressures and right ventricular dimensions at the one-month follow-up. The case highlights the rare association of the levoatriocardinal vein and cor triatriatum, and its presence signifies severe obstruction at the level of cor triatriatum.