Which congenital heart defect is associated with early cyanosis?

Tetralogy of Fallot is a congenital heart defect characterized by a combination of four specific cardiac anomalies: ventricular septal defect, right ventricular outflow tract obstruction (often due to pulmonary stenosis), right ventricular hypertrophy, and an aorta that is positioned over the ventricular septal defect (overriding aorta). This defect leads to decreased blood flow to the lungs and allows deoxygenated blood to flow into the systemic circulation due to the shunting through the ventricular septal defect.

As a result, individuals with Tetralogy of Fallot often present with early cyanosis, a bluish discoloration of the skin due to low levels of oxygen in the blood. This cyanosis typically occurs during episodes of increased right-to-left shunting, especially when the child exerts themselves, leading to a "tet spell," which further exacerbates the right-to-left shunting and subsequent cyanosis.

In contrast, other congenital heart defects listed may present with different clinical manifestations. For instance, a ventricular septal defect and an atrial septal defect typically lead to increased pulmonary blood flow, which does not cause early cyanosis. Pulmonary stenosis can cause pressure overload but also tends to result in obstructive pathology without the same level of de