Sinus Venosus Atrial Septal Defect: A Challenging Diagnosis

Sinus venosus atrial septal defect (SVASD) is a rare adult congenital heart disease which permits shunting of blood from the systemic to the pulmonary circulation and is commonly associated with anomalous pulmonary venous return. We report a case of a 27-year-old man with a history of premature birth and unilateral cryptorchidism who was admitted for syncope. Electrocardiogram (ECG) demonstrated atrial fibrillation (AF)and S1Q3T3 pattern along with an incomplete right bundle branch block. Transthoracic echocardiography (TTE) suggested the presence of right ventricular pressure and volume overload and severe right ventricular and right atrial enlargement. The agitated saline study was negative suggesting no inter-atrial communication. Transesophageal echocardiography (TEE) demonstrated a superior SVASD and raised the possibility of an anomalous pulmonary venous connection. Chest computed tomography identified the right superior pulmonary vein connection to the superior vena cava. The diagnosis of SVASD poses multiple challenges from the variety of symptoms to the selection of appropriate imaging and the complexity of surgical treatment.