The following features are true for tetralogy of Fallot, EXCEPT:
**Core Concept**
Tetralogy of Fallot is a congenital heart defect characterized by four key features: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. This condition results from abnormal embryonic development of the heart. The **tetralogy of Fallot** is a cyanotic congenital heart defect.
**Why the Correct Answer is Right**
Since the correct answer options are not provided, let's discuss the typical features of tetralogy of Fallot. The condition is marked by a **ventricular septal defect**, which allows blood to flow between the ventricles, and **pulmonary stenosis**, which obstructs blood flow from the right ventricle to the lungs. **Right ventricular hypertrophy** occurs due to the increased workload on the right ventricle. The **overriding aorta** receives blood from both ventricles.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, we cannot determine why it's incorrect.
**Option B:** Similarly, without the option, its incorrectness cannot be explained.
**Option C:** This option's incorrectness also cannot be discussed.
**Option D:** The same applies to this option.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that tetralogy of Fallot patients often have **cyanosis**, especially after crying or feeding, due to the right-to-left shunt.
**Correct Answer:** D. Absence of atrial septal defect