Total Anomalous Pulmonary Venous Return 

• Not all pulmonary veins connect to the left side of the heart as they should, instead they connect to veins/structures of the right side of the heart.
• The left side receives blood because of the defects that are usually present along with these one: Atrial septal defect and foramen ovale (opening between atria which is supposed to close at birth but remains open in total anomalous pulmonary venous return).