Congenitally Corrected Transposition of the Great Arteries

Problems Commonly Associated with Congenitally Corrected Transposition of the Great Arteries

Most babies born with congenitally corrected transposition of the great arteries also have other heart defects. Each condition has a treatment option. Depending on how serious each abnormality is, surgery may be necessary anytime from early infancy to adulthood. These defects include:

Ventricular septal defect (VSD)
This defect allows blood to mix between the two ventricles and may dilate and weaken the ventricles since they work harder because of increased blood volume. It may also allow venous (unoxygenated — blue) blood to mix with arterial (oxygenated — red) blood and give a bluish tinge to the skin, called cyanosis.

Obstruction of blood to the lungs because of narrowing beneath the pulmonary artery (pulmonary stenosis)
This obstruction makes the left ventricle work harder, but the left ventricle was built to pump at a higher pressure anyway.

Tricuspid valve regurgitation
The valve that enters the right ventricle (atrioventricular or AV valve) is the tricuspid valve and is a thin and delicate structure. In a normal heart, it functions in the low-pressure pulmonary circulation. In this anomaly, however, since the ventricles are "switched" or transposed, the valve is exposed to high pressure in the right ventricle. This pressure may cause the valve to leak blood backwards (regurgitation).

As the right ventricle weakens and dilates with time it may pull the cusps of the tricuspid valve apart, causing it to leak even more. This is an added burden for the right ventricle, which has to pump blood to the body, but also has to cope with a leaky valve. The added burden may hasten its deterioration in function.

Sometimes the systemic valve is intrinsically abnormal. Because this tricuspid valve usually sits in the right ventricle on the other side of the heart, it is called a left-sided or systemic AV valve since it is in the patient's left chest. This helps avoid confusion when describing the AV valves.

Complete heart block
Because the ventricles are reversed, the conducting pathways in the heart are thin and fragile and may not conduct the electrical impulses around the heart normally. Thus, there is an increased chance of interruption of the electrical impulses before they reach the bottom chambers. This is called complete heart block and may need to be remedied with a pacemaker.