total anomalous venous return [L, totus, whole; Gk, anomalos, uneven; L, vena, vein; ME, retournen, to turn back] , a rare congenital cardiac anomaly in which the pulmonary veins attach to the right atrium or to various veins draining into the right atrium rather than to the left atrium. These alternate pathways of venous return to the left-sided circulation may be insufficient and cause obstruction, resulting in symptoms. Clinical manifestations include cyanosis, pulmonary congestion, and heart failure. Other cardiac defects also may be present, such as atrial septal defect, which shunts blood from the right atrium to the left atrium and helps decompress the right atrium. Corrective surgery is indicated, usually after 1 year of age, but may be necessary at an earlier age if pulmonary venous obstruction or severe congestive heart failure is present. See also congenital cardiac anomaly.
