Normal                                 Transposition
   

In this situation, the pulmonary arteries are supplied by the left ventricle, and the aorta by the right ventricle.

This, of course, is the opposite of the normal arrangement. Infants can only survive if there is a shunt between the two sides of the heart, and an atrial septal defect needs to be actually enlarged to allow adequate mixing of blood to deliver enough oxygenated blood to the body. Significant advances have been made in the surgical treatment of this disorder.
  ©COPY: 1997 HeartPoint Updated November 1997