Fallot

Fallot most commonly refers to the Tetralogy of Fallot, a congenital heart defect named for the French physician Étienne-Louis Arthur Fallot who first described it in 1888. The condition comprises four anatomical abnormalities: a ventricular septal defect, pulmonary stenosis (often subpulmonary), an overriding aorta, and right ventricular hypertrophy. The combination causes a right-to-left shunt of blood and reduced pulmonary blood flow, resulting in cyanosis that varies with the degree of obstruction.

Clinical features include cyanosis in infancy, variable heart murmur, and episodes known as “tet spells” characterized by sudden dyspnea and irritability; older children may adopt a squatting position to increase systemic vascular resistance and decrease shunting. Associated conditions include genetic syndromes such as 22q11.2 deletion.

Diagnosis is based on history and physical examination, with imaging confirming anatomy. Echocardiography is the primary modality, showing the VSD, RV outflow tract obstruction, and overriding aorta. Electrocardiography may show right ventricular hypertrophy; chest radiography often shows a boot-shaped heart.

Management typically involves surgical repair in infancy. Definitive treatment includes closure of the VSD and relief of right ventricular outflow tract obstruction, often with a patch. Some patients may require initial palliation before complete repair. With modern surgical techniques and long-term follow-up, many individuals live near-normal lifespans, though long-term risks include residual outflow obstruction, pulmonary regurgitation, arrhythmias, and other complications; lifelong cardiology follow-up is recommended.