Bilateral superior vena cava with right superior vena cava draining into left atrium

Anomalies of systemic venous return are extremely heterogeneous congenital malformations with variable ranges from completely normal physiology to severe forms of right to left shunting requiring surgical treatment. Anomalous drainage of a right-sided superior vena cava (SVC) to the left atrium (LA) is one of the rarest variants of systemic venous return anomalies, characterized by right-to-left shunt physiology and cyanosis. Here we report a 2 years old girl presented with cyanosis which was observed shortly after birth by her parents but not further investigated. She is otherwise active girl and with normal growth and development. Her clinical examination was unremarkable apart from mild clubbing of the fingers and low oxygen saturation of 88-90% in room air. Her ECG and chest X-ray were unremarkable. Echocardiography showed bilateral SVC connected by a small innominate vein. The right SVC drains directly into the LA while the left SVC drains into the right atrium (RA) via a dilated coronary sinus. There is a small superior sinus venosus type atrial septum defect (ASD) with left to right shunt. Also, there is partial anomalous pulmonary venous return with right upper and right middle pulmonary veins draining directly into the right SVC, which is connected to LA. The right lower pulmonary vein and left pulmonary veins drain directly to LA. The rest of her echocardiography demonstrated normal heart structures and function. This patient was referred for surgical correction, including baffling of the right SVC to the RA and closure of the ASD. We describe this case to highlight the importance of recognizing this rare anomalous systemic venous connection as one of the very rare causes of cyanosis in the pediatric age group as well as at older age.