Which of the following is NOT a defect associated with Tetralogy of Fallot (TET)?

Tetralogy of Fallot is a congenital heart defect characterized by a specific combination of four abnormalities. These include pulmonic stenosis, right ventricular hypertrophy, ventricular septal defect, and overriding aorta. Among these defects, an atrial septal defect (ASD) is not inherently part of the classic presentation of Tetralogy of Fallot.

When considering the components of Tetralogy of Fallot, pulmonic stenosis is a narrowing at the right ventricular outflow tract, which obstructs blood flow to the lungs. Right ventricular hypertrophy occurs due to increased workload on the right ventricle as it pumps against this obstruction. The ventricular septal defect is a hole between the left and right ventricles, which leads to the mixing of oxygenated and deoxygenated blood. The absence of an ASD in this context is crucial, as an ASD represents a different type of defect, involving the septum between the atria rather than the ventricles.

This distinction is important in understanding the pathophysiology of Tetralogy of Fallot and how it differs from other congenital heart defects that may also involve septal defects.