Transposition of the great arteries is a serious but rare heart defect present at birth (congenital), in which the two main arteries leaving the heart are reversed (transposed).
Transposition of the great arteries changes the way blood circulates through the body, leaving a shortage of oxygen in blood flowing from the heart to the rest of the body. Without an adequate supply of oxygen-rich blood, the body can't function properly and your child faces serious complications or death without treatment.
Transposition of the great arteries is usually detected either prenatally or within the first hours to weeks of life.
Corrective surgery soon after birth is the usual treatment for transposition of the great arteries. Having a baby with transposition of the great arteries can be alarming, but with proper treatment, the outlook is promising.
Transposition of the great arteries care at Mayo Clinic