Tetralogy of fallot Health Dictionary

A form of congenital heart disease in which the heart has 4 coexisting anomalies: displacement of the aorta, narrowing of the pulmonary valve, a hole in the ventricular septum, and thickening of the right ventricle wall. These cause poor oxygenation of the blood pumped to the body, resulting in cyanosis and breathlessness. Tetralogy of Fallot occurs in about 1 in 1,000 infants. Affected infants appear normal at birth. Severely affected infants may become cyanosed and breathless early in life. Other symptoms include failure to gain weight and poor development.

An ECG, echocardiogram (see echocardiography), and sometimes cardiac catheterization are performed to confirm the diagnosis and assess the severity of the condition. The disorder is corrected by open heart surgery.

The most common form of cyanotic congenital heart disease. The tetralogy consists of stenosis of the pulmonary valve (see PULMONARY STENOSIS); a defect in the septum separating the two ventricles (see VENTRICLE); the AORTA over-riding both ventricles; marked HYPERTROPHY of the right ventricle. Surgery is required to remedy the defects.

a form of congenital heart disease in which there is *pulmonary stenosis, enlargement of the right ventricle, a *ventricular septal defect, and in which the origin of the aorta lies over the septal defect. The affected child is blue (cyanosed) and frequently squats. The defect is corrected surgically. [E. L. A. Fallot (1850–1911), French physician]