Transposition of the great arteries (TGA) is a congenital heart defect in which the aorta, which normally arises from the left ventricle, leaves the right ventricle instead (see fig. 1 and 2). The pulmonary artery, which normally arises from the right ventricle, leaves the left ventricle instead. As a result, oxygen-poor blood is pumped to the body and oxygen-rich blood is pumped to the lungs. Other defects are commonly associated with TGA including: atrial septal defect (ASD), ventricular septal defect (VSD), or patent ductus arteriosus (PDA).
This condition can be surgically corrected using a procedure known as an arterial switch operation. The coronary arteries are cut away from the base of the aorta. The aortic and pulmonary valves are divided from the aorta and pulmonary artery (see fig. 3). The pulmonary artery is then moved in front of the aorta and the valves are attached. The coronary arteries are attached to the valve that has now become the aortic valve (see fig. 4).
Figure 1: Cut away view of the normal heart.
Figure 2: Transposition of the great arteries.
Figure 3: Coronary arteries are cut from base of aorta and the aortic and pulmonary valves are divided from the aorta and pulmonary artery.
Figure 4: Finished surgical repair.
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