Transposition of the great vessels

Alternative names:

transposition of the great arteries

Definition:

A congenital heart defect in which the position of the two major vessels that carry blood away from the heart, the aorta and the pulmonary artery, is transposed.

Causes, incidence, and risk factors:

The cause of most congenital heart defects is unknown. Prenatal factors that are associated with a higher than normal incidence of the disease include maternal rubella or other viral illnesses during pregnancy, poor prenatal nutrition, maternal alcoholism, maternal age over 40, and diabetes.

Transposition of the great vessels is classified as a cyanotic heart defect because the condition results in insufficiently oxygenated blood pumped to the body which leads to cyanosis (a bluish-purple coloration to the skin) and shortness of breath.

In transposition of the great vessels, there is no communication between the pulmonary circulation and the systemic circulation. There is usually an associated defect that permits the mixing of the systemic and pulmonary circulation to provide some oxygenated blood to the body. Without such a defect, the condition is fatal. Symptoms appear at birth or very soon afterwards. The severity of the symptoms depends upon the type of associated defect and the resulting amount of oxygenated blood supplied to the general circulation. The condition affects approximately 40 out of 100,000 infants.