heart author" faq
Transposition of the Great Arteries


In d-transposition of the great arteries, the aorta arises in an anterior position from RV and the pulmonary artery arises from LV (see figure 23e). In two thirds of cases the ductus arteriosus (see figure 22) and foramen ovale allow communication between the aortic and pulmonary circulations. Severe cyanosis is present. The one third with other defects that permit intracardiac mixing (i.e. ASD figure 20, VSD figure 21, PDA figure 22) are less critically ill with loss ofsevere cyanosis, but they are at risk of LV failure.

Findings include cyanosis and heart murmur. RVH (increased RV wall thickness) or LVH (increasedLV wall thicckness) may be present. Chest X ray shows heart enlargement.

Immediate management involves creating intracardiac mixing or increasing its extent:
1) use of infusing of medication, prostaglandine E, to maintain or restore patency of ductus arterioses, the creation of an ASD or both. Also, oxygen is administered to most patients (to decrease pulmonary [lung] vascular (blood vessel) resistance and to increase lung blood flow), as are digoxin and diuretic drugs like diuril or lasix (to treat heart failure).

Two surgical operations have been used (see figure 23e regarding the atrial switch operation). The atrial switch operation as shown in figure 23 E has been replaced by the arterial switch operation in which the pulmonary artery and ascending aorta are transected above the semilunar valves and coronary arteries (see figure 23e), and then switched, so that the aorta is connected to the neoaortic valve (formerly the pulmonary valve) arising from the left ventricle (LV), and the pulmonary artery is connected to the neopulmonary valve (formerly the aorta valve) arising from the RV (see figure 23e). The coronary arteries are relocated to the neoaorta to restore normal coronary circulation. This operation can be performed in neonates (newly born) and is associated with a low operative mortality and an excellent long-term outcome.