Transposition of the Great Arteries (TGA)

Transposition of the great arteries (TGA) is an abnormally developed heart. This condition is congenital. This means that your baby is born with it.  

In this condition, the large blood vessels that carry blood from the heart to the lungs and body aren’t connected as they should be. The aorta is connected to the right ventricle. It should be connected to the left ventricle. The pulmonary artery is connected to the left ventricle when it should be connected to the right ventricle. In TGA, the following occurs:

  • Oxygen-poor (blue) blood is sent to the body.
  • Oxygen-rich (red) blood return to the lungs.

This is the opposite of a normal heart.

Babies cannot live with this condition unless they get treatment.

TGA may occur on its own. Or your child may also have other heart problems. Sometimes the other heart issues help a child with TGA to live. Other heart problems may allow some oxygen to be sent to your baby’s body. Heart defects that can happen with TGA include:

  • An opening in the ventricular septum, which divides the two lower chambers of the heart. This allows oxygen-poor and oxygen-rich blood to mix. 
  • The ductus arteriosus stays open. This is a blood vessel that carries blood away from the heart in a developing baby. It usually closes soon after birth. This causes oxygen-poor and oxygen-rich blood to mix.
  • The blood flow from the left lower chamber of the heart (ventricle) may be blocked (obstructed).