What are the 4 components of Tetralogy of Fallot?

From the Guidelines

The 4 components of Tetralogy of Fallot are subpulmonary infundibular stenosis, a ventricular septal defect (VSD), an overriding aorta, and right ventricular (RV) hypertrophy.

Key Characteristics

• The VSD is usually large and single, located in the subaortic position 1
• The aorta overrides the VSD by less than 50% of its diameter 1
• RV hypertrophy is a key component, resulting from the increased workload on the right ventricle 1
• Associated anomalies, such as pulmonary artery hypoplasia or stenosis, coronary artery anomalies, and right aortic arch, can occur in some cases 1

From the Research

Components of Tetralogy of Fallot

The four components of Tetralogy of Fallot are:

• A large malalignment ventricular septal defect (VSD) or interventricular communication 2, 3, 4, 5, 6
• Obstruction of the right ventricular outflow tract, which can include infundibular and valvular pulmonary stenosis 2, 3, 4, 5, 6
• Override of the ventricular septum by the aortic root, also known as an overriding aorta 2, 3, 4, 5, 6
• Right ventricular hypertrophy 2, 3, 4, 5, 6

Variations and Associations

These components can vary in severity and may be associated with other cardiac and extracardiac abnormalities, such as:

• Pulmonary atresia with VSD and absent pulmonary valve syndrome 3
• Major aortopulmonary collateral arteries (MAPCAs) 3
• Atrial septal defect (ASD), also known as Pentalogy of Fallot 3
• Right aortic arch and coronary abnormalities 3