TETRALOGY OF FALLOT: ORIGIN, DIAGNOSIS, AND PATHOLOGICAL CHANGES

Tetralogy of Fallot (see Tetralogy of Fallot image) accounts for 7-10% of all congenital heart defects. Associated anomalies include right aortic arch defects (25%), altered coronary artery anatomy (5-10%), pulmonary artery stenosis, presence of aortopulmonary collateral vessels, patent ductus arteriosus, complete atrioventricular septal defect, atrial septal defect, and accessory septal valve defect. Tetralogy of Fallot has 4 features: a large ventricular septal defect, obstruction of the right ventricular outflow tract and pulmonary valve stenosis, right ventricular hypertrophy, and dextroposition of the aorta. Symptoms include cyanosis, dyspnea on feeding, poor growth rate, and severe hypercyanotic symptoms (sudden, potentially fatal episodes of severe cyanosis). A coarse systolic murmur is often heard at the upper left sternal border, with a single second heart sound (S2). The diagnosis is made by echocardiography. The definitive treatment is surgical repair of the defect.