Right superior vena cava draining into the left atrium: prenatal diagnosis and postnatal management.

Right superior vena cava (RSVC) draining into the left atrium, causing hypoxemia, represents a very rare congenital malformation which has not previously been described in the fetus. We describe a case in which fetal echocardiography at 22 weeks' gestation revealed an enlarged superior vena cava connecting abnormally with a mildly enlarged left atrium. Neonatal transthoracic echocardiography confirmed the diagnosis and showed an abnormal connection of the right pulmonary veins to the RSVC. Right-to-left shunt due to anomalous drainage of the RSVC into the left atrium associated with an atrial septal defect and anomalous pulmonary venous return were diagnosed on echocardiography and confirmed by angiography. The newborn was hemodynamically stable at birth and at the 1-year follow-up.