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Congenital Heart Disease

Providers: Stout, Karen K. Last Updated: Tuesday, May 15, 2007

At least a million adults in the United States have congenital heart disease. They are not your typical cardiac patients: they have “funny” plumbing. This population is growing, thanks to increased survival rates among children with heart defects. Nearly 1 percent of children are born with a heart defect. In 1940, 80 percent of children with the more rare forms of congenital heart disease died before reaching adulthood. Now over 80 percent survive into adulthood, thanks to advances in cardiac surgery. Because of these gains in patient longevity, and because childhood cardiac surgeries often need follow-up repairs years later, there is a growing need for treatment of congenital heart defects in the adult population.

Congenital heart disease is a physiological abnormality of the heart and its attached blood vessels. It occurs in three forms: simple, complex, and super-complex. The simple form includes the most common type of congenital heart defect: the septum hole. The heart has two sides, right and left, and the septa separate these sides from each other, preventing deoxygenated blood on the right side from mixing with oxygenated blood on the left side. When there are holes in a septum, the heart cannot pump blood as efficiently as it was designed to. Some septum holes, especially those between the right and left ventricles (lower heart chambers), tend to close on their own, without surgery. Other holes, especially those between the right and left atria (upper heart chambers), are bigger. These holes often require a procedure in which a surgeon makes a small incision and snakes a tube (catheter) through a blood vessel into the heart. The surgeon then “patches” the septum hole with a metal prosthesis.

An example of the complex form of congenital heart disease is a defect called tetralogy of Fallot. Infants with tetralogy of Fallot have 1) a large hole in the ventricular septum, 2) an aorta that attaches to both the right and left ventricle, instead of just the left ventricle (this “double attachment” allows deoxygenated blood from the right ventricle to dilute the oxygenated blood traveling from the left ventricle to the rest of the body), 3) a narrowing of the pulmonary artery, which routes deoxygenated blood from the right ventricle to the lungs, and 4) a thickened right ventricle wall. Taken together, these defects make it difficult for the heart to pump enough oxygenated blood to the tissues. Infants with this disorder have bluish skin (blood without oxygen is blue) and sometimes have difficulty breathing. Tetralogy-of-Fallot defects are usually corrected with surgery in infancy, but repairs to the surgery may be needed in adulthood.

An example of the super-complex form of congenital heart disease is transposition of the great vessels (sometimes called transposition of the great arteries). In this defect, the aorta and pulmonary artery are each attached to the heart in place of the other. For example, the aorta is attached to the right ventricle instead of the left ventricle. As a result, this mismatched aorta sends deoxygenated blood from the right ventricle straight back to the body, bypassing the lungs. Similarly, the pulmonary artery is attached to the left ventricle instead of the right ventricle. As a result, oxygenated blood in the left ventricle runs in a closed loop—from the left ventricle, to the lungs, then back to the left ventricle—bypassing the body. Infants can survive this disorder for a few days because there are two “leak points” between the left and right portions of the fetal heart. These leak points, which close several days after birth, allow a small amount of oxygenated blood to reach the body. Treatment for an infant with transposed vessels always requires immediate surgery.
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