What is corrected transposition of the great arteries?
Corrected transposition of the great arteries is a very rare heart defect in which the heart’s lower two chambers, the ventricles, are reversed in their positions. It affects about 1 in 25,000 births and occurs equally in boys and girls. Early in fetal life the heart first forms in the shape of a tube. This tube bends and folds in on itself, creating the four heart chambers and the four heart valves. (Click here to learn more about normal hearts). If the tube bends to the left instead of the right, the ventricles are reversed: the right ventricle is on the left (1) and the left ventricle is on the right (2). Two of the heart valves “follow ” the ventricles so they are also reversed: the mitral valve (3) is on the right and the tricuspid valve (4) is on the left. Although the two heart valves and the two great arteries (the pulmonary artery (5) and the aorta (6) are transposed or exit from the “wrong” ventricle, the blood flows to the correct place because the ventricles are also revers
