Right superior vena cava draining in the left atrium associated with tetralogy of Fallot and pulmonary atresia
A 3-month-old girl delivered at term by normal vaginal delivery was referred to our institution with persistent cyanosis and respiratory distress since 2 weeks. She has a sister who had surgical repair of tetralogy of Fallot (TOF). When admitted, she was mechanically ventilated; her vital signs showed oxygen saturation of 50% on FiO2 of 100%; her blood pressure was 100/90 mmHg; and heart rate was 100-140 beats per min. Chest roentgenogram demonstrated cardiomegaly with central congestion and oligemic left lung with a band of atelectasis in the right upper lobe.\nAn echocardiographic study showed situs solitus, levocardia, d-looped ventricles, and normally related great arteries. It also showed TOF, pulmonary atresia (PA) with absent main pulmonary artery and hypoplastic (possibly confluent) pulmonary artery branches. There were major aortopulmonary collateral arteries (MAPCAs) supplying the hypo plastic pulmonary arteries. The inter-atrial septum was intact and the right superior vena cava (RSVC) was mildly dilated, draining into the left atrium (LA) [Figures and ]. The pulmonary veins were well seen and were normally draining to the LA, whereas the inferior vena cava and the hepatic veins drain into the right atrium. The LA, Left ventricle (LV), aortic root, and descending aorta were mildly dilated.\nThe LV systolic functions were good while right ventricle functions were fair to good.\nA cardiac computed tomography (CT) confirmed that superior vena cava (SVC) drains into the roof of the LA without communication with the right side system, whereas inferior vena cava does appear to drain into the right atrium with intact inter-atrial septum. The pulmonary veins were well visualized and draining to the LA. The right ventricle was small, with minimal contrast seen within. There were at least two collateral vessels arising from the aorta. The inferior collateral supplied the right lower lobe pulmonary artery and the more superior collateral vessel appeared to connect to the pulmonary artery confluence which then bifurcated into two hypoplastic pulmonary arteries. There was suspicion of presence of secondary supply to the left main pulmonary artery, as the peripheral left pulmonary artery appears of better caliber [; ].\nA diagnostic cardiac catheterization was performed. An injection in a peripheral vein in the left arm showed draining of the left innominate vein to the RSVC and consequently into the posterior LA []. It also delineated the presence of MAPCAs originating from the descending aorta and joining the hypoplastic pulmonary arterial tree. There were also two stenotic sites at the proximal parts of the pulmonary artery branches and normal pulmonary venous pattern