All except one is false regarding tetrology of fallot
**Core Concept**
Tetralogy of Fallot (TOF) is a congenital heart defect characterized by four classic features: ventricular septal defect (VSD), pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. This condition leads to reduced blood flow to the lungs and increased oxygen extraction from the blood, resulting in cyanosis.
**Why the Correct Answer is Right**
The correct answer is the statement that accurately describes a characteristic of Tetralogy of Fallot. TOF is indeed characterized by all four classic features mentioned. The pathophysiology involves a VSD, which allows blood to flow from the left to the right ventricle, bypassing the pulmonary valve and leading to decreased pulmonary blood flow. This results in right ventricular hypertrophy due to the increased resistance against which the right ventricle must pump.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Tetralogy of Fallot is characterized by pulmonary stenosis, not pulmonary hypertension. While pulmonary hypertension can be a complication of TOF, it is not a defining feature of the condition.
**Option B:** This option is incorrect because the aorta is indeed "overriding" in Tetralogy of Fallot, meaning it is positioned over the VSD and receives blood from both ventricles.
**Option C:** This option is incorrect because while patients with Tetralogy of Fallot may have a higher risk of endocarditis, it is not a defining feature of the condition.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of Tetralogy of Fallot is the presence of a harsh, pansystolic murmur heard over the left upper sternal border, which is due to the turbulent blood flow across the VSD. This murmur is often described as a "diamond-shaped" murmur due to its characteristic shape on the phonocardiogram.
**Correct Answer: B. The aorta is indeed "overriding" in Tetralogy of Fallot, meaning it is positioned over the VSD and receives blood from both ventricles.**