An aortopulmonary window is a heart defect in which there is a hole between the blood vessel that feeds the heart (the aorta) and the blood vessel going to the lungs (pulmonary artery). Because of this hole, blood from the aorta rushes into the pulmonary artery, and too much blood flows through the lungs.
Aortopulmonary window is rare — it accounts for less than 0.1 percent of all congenital heart defects. It is a type of congenital heart defect, meaning a baby is born with it.
About 50 percent of children with this heart condition also have another type of heart defect.
If left untreated, aortopulmonary window can lead to high blood pressure in the lungs (pulmonary hypertension) and heart failure. Treatment usually involves surgery to patch the hole.