Which radiographic finding is classically associated with Tetralogy of Fallot?

Which radiographic finding is classically associated with Tetralogy of Fallot?

• A. Egg-shaped heart
• B. Boot-shaped heart on chest radiograph
• C. Normal chest radiograph
• D. Cardiomegaly with edema

Answer: (B)

Tetralogy of Fallot typically presents with a boot-shaped heart on chest radiograph because the right ventricular outflow tract obstruction drives right ventricular hypertrophy, which lifts and rounds the apex and shifts the cardiac silhouette upward and toward the left. This creates the distinctive contour that looks like a boot. The reduced flow through the pulmonary outflow also often leads to diminished pulmonary vascular markings, reinforcing the abnormal silhouette. In contrast, an egg-shaped heart is not the characteristic sign of TOF (it’s more associated with other conditions like transposition in some descriptions), a normal chest radiograph would not show this silhouette, and cardiomegaly with edema points toward heart failure rather than TOF.

Tetralogy of Fallot typically presents with a boot-shaped heart on chest radiograph because the right ventricular outflow tract obstruction drives right ventricular hypertrophy, which lifts and rounds the apex and shifts the cardiac silhouette upward and toward the left. This creates the distinctive contour that looks like a boot. The reduced flow through the pulmonary outflow also often leads to diminished pulmonary vascular markings, reinforcing the abnormal silhouette. In contrast, an egg-shaped heart is not the characteristic sign of TOF (it’s more associated with other conditions like transposition in some descriptions), a normal chest radiograph would not show this silhouette, and cardiomegaly with edema points toward heart failure rather than TOF.