Partial anomalous pulmonary venous connection (PAPVC) or partial anomalous pulmonary venous return (PAPVR) is a congenital heart defect characterized by the abnormal connection of one or more pulmonary veins to the systemic circulation, instead of draining into the left atrium. This results in a portion of oxygen-rich blood returning to the right side of the heart, causing an increased workload on the right side and potential complications.