The Heart Institute

Transposition of the Great Arteries

In the normal heart, the right side of the heart pumps ‘blue’ blood (un-oxygenated) from the body to the lungs through the pulmonary artery (main artery to the lungs), while the left heart pumps “red” blood (oxygenated) from the lungs to the body through the aorta (main artery to the body).

In this defect, the position of the main vessels to the lungs and body is reversed so that the aorta arises from the right side of the heart and the pulmonary artery form the left side of the heart. The consequences of this reversal are severe, since blood which has gone to the lungs to pick up oxygen is not pumped to the body as it should be, but instead returns to the lungs. The only way blood with oxygen can reach the body is by passing through a hole between the upper collecting chambers and mixing with the “blue” blood.

The surgeons perform an arterial switch procedure for this anomaly, which connects the aorta to the left ventricle and connects the pulmonary artery to the right ventricle.

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