Tetralogy of fallots includes all except –
**Core Concept**
Tetralogy of Fallot is a congenital heart defect characterized by four key components: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. This complex anomaly results from abnormal development of the heart during embryogenesis.
**Why the Correct Answer is Right**
The correct answer must exclude one of the four characteristic components of Tetralogy of Fallot. This requires understanding the pathophysiology and embryological development of the heart. The four components are essential to diagnose and treat this condition effectively. The ventricular septal defect allows blood to flow between the ventricles, while pulmonary stenosis restricts blood flow to the lungs. Right ventricular hypertrophy is a compensatory response to increased resistance in the pulmonary artery. The overriding aorta receives blood from both ventricles.
**Why Each Wrong Option is Incorrect**
**Option A:** Ventricular septal defect is a characteristic component of Tetralogy of Fallot, so this option is incorrect.
**Option B:** Pulmonary stenosis is another key component of Tetralogy of Fallot, making this option incorrect as well.
**Option C:** Right ventricular hypertrophy is a compensatory response to increased resistance in the pulmonary artery, which is also a characteristic component of Tetralogy of Fallot, so this option is incorrect.
**Option D:** The overriding aorta is a characteristic component of Tetralogy of Fallot, therefore, this option is incorrect.
**Clinical Pearl / High-Yield Fact**
Tetralogy of Fallot is often associated with other congenital anomalies, such as atrial septal defects, patent ductus arteriosus, and tricuspid atresia. A thorough physical examination, including signs of cyanosis and clubbing, is essential for early diagnosis.
**Correct Answer:** D. The overriding aorta is not an option in this question.