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 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 occurs during fetal growth when your baby’s heart is developing. Why this defect occurs is unknown in most cases.
Normally, the pulmonary artery — which carries blood from your heart to your lungs to receive oxygen — is attached to the lower right chamber (right ventricle). From your lungs, the oxygen-rich blood goes to your heart’s upper left chamber (left atrium), through the mitral valve into the lower left chamber (left ventricle). The aorta is normally attached to the left ventricle. It carries oxygen-rich blood out of your heart back to the rest of your body.
In transposition of the great arteries, the positions of the pulmonary artery and the aorta are switched. The pulmonary artery is connected to the left ventricle, and the aorta is connected to the right ventricle. Oxygen-poor blood circulates through the right side of the heart and back to the body without passing through the lungs. Oxygen-rich blood circulates through the left side of the heart and right back into the lungs without being circulated to the rest of the body.
Circulation of oxygen-poor blood through the body causes the skin to have a blue tint (cyanosis). Because of this, transposition of the great arteries is called a congenital cyanotic heart defect.
Although some factors, such as rubella or other viral illnesses during pregnancy, maternal age over 40, or maternal diabetes, may increase the risk of this condition, in most cases the cause is unknown.
Transposition of the great arteries symptoms include:
- Blue color of the skin (cyanosis)
- Shortness of breath
- Lack of appetite
- Poor weight gain
When to see a doctor
Transposition of the great arteries is often detected as soon as your baby is born or during the first week of life. If signs and symptoms didn’t appear in the hospital, seek emergency medical help if you notice that your baby develops bluish discoloration of the skin (cyanosis), especially involving the lips and face.