Transposition of the greater arteries

Transposition of the great arteries

With this defect, the positions of the aorta — the main artery leading away from the heart — and the pulmonary artery, which leads to the lungs, are reversed (transposed). The aorta and pulmonary arteries are, together, sometimes referred to as the great arteries. The aorta arises from the right ventricle instead of the left ventricle. The pulmonary artery also arises from the left ventricle instead of the right. This prevents nourishing oxygenated blood from reaching the body.

This condition would quickly be fatal to a newborn except it's generally accompanied by another defect — commonly a septal defect or patent ductus arteriosus — that allows oxygen-rich blood to get to the body. Surgery to repair the condition is usually necessary shortly after birth.