What is it ?
A defect that develops in the fetus in which there is a narrowing of the aortic arch, the main blood artery that delivers blood from the left ventricle of the heart to the rest of the body.

Coarctation of the aorta is diagnosed in both newborns and adults. Approximately 10% of newborns with congenital heart disease have coarctation of the aorta. Blood leaves the heart by way of the left ventricle and is distributed to the body by arteries. The aortic arch is the first artery to carry blood as it leaves the heart.

Other arteries to the head and arms branch off the aortic arch. A narrowing of the aorta at any spot produces resistance to the flow of blood. This causes high blood pressure before the narrowing and low pressure below the narrowing (downstream). Parts of the body supplied by arteries that branch off the aortic arch before the narrowing have high blood pressure, while most of the lower body doesn't receive enough blood supply. To compensate for this, the heart works harder, and the blood pressure rises. Approximately half of all infants with coarctation of the aorta are diagnosed within the first two months of life.

Frequently, there are other congenital cardiac complications present. Infants with Turner syndrome have a 45% rate of also having coarctation. There is evidence that some cases of coarctation may be inherited. In newborns with congenital heart disease, coarctation of the aorta develops while the baby is in the womb. Among the consequences of coarctation of the aorta is ventricular hypertrophy, an enlarging of the left ventricle in response to the increased back pressure of the blood and the demand for more blood by the body.

Symptoms in infants include shortness of breath, difficulty in feeding, and poor weight gain. Older children usually don't have symptoms, but may display fatigue, shortness of breath, or a feeling of lameness in their legs. Infants usually have an abnormal "gallop" heart rhythm and may also have heart murmurs. Sometimes excessive arterial pulses can be seen in the carotid and suprasternal notch arteries, indicating increased pressure in these arteries, while the femoral pulse is weak or can't be detected. The systolic pressure is higher in the arms than in the legs.

Enlargement of the heart can be seen in x rays. Similar symptoms are seen in older children and adults. A 10 mm Hg (mercury) pressure difference between the upper and lower extremities is diagnostic for coarctation of the aorta. For some patients, the systolic pressure difference is observed only during exercise.

Infants frequently have an abnormal electrocardiogram (ECG) that indicates that the right or both ventricles are enlarged, while in older children the ECG may be normal or show that the left ventricle is enlarged. The coarctation may be detected in echocardiographic examination.