Partial abnormal drainage of superior and inferior caval veins into the left atrium: two case reports.

Abnormal connection of the right superior caval vein to the left atrium is an uncommon systemic vein drainage anomaly, with only a few cases reported among congenital heart disease (CHD), around 20 cases published in the medical literature. The inferior vena cava connection with the left atrium, also very rare, can appear directly or in heterotaxy. Clinical suspicion arises due to the presence of cyanosis in the absence of other specific clinical signs (without other associated CHD). We present the cases of two children with abnormal superior and inferior systemic venous return. The first case is an abnormal connection of right superior vena cava to the left atrium associated with persistent left superior vena cava draining into the right atrium through the coronary sinus. The second case is an interruption of the inferior vena cava with hemiazygos continuation, drained into the left superior vena cava, which drained into the left atrium. The diagnosis was imagistic echocardiography and angiography. Surgical treatment solutions vary from one case to another, usually following anatomic correction. Hypoxia accompanied by cyanosis must bring into question the pathology of systemic venous drainage anomaly, after other common causes have been excluded. Surgery is indicated in all cases due to the risk associated with the presence of right-to-left shunt.