A child has cyanotic disease with left ventricular enlargement wiht left axis detion. Probable diagnosis Is –
**Core Concept**
Tetralogy of Fallot (TOF) is a congenital cyanotic heart defect characterized by four key features: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta. The presence of left ventricular enlargement and left axis deviation suggests an altered hemodynamic profile, which is a hallmark of TOF.
**Why the Correct Answer is Right**
In TOF, the right ventricular outflow tract obstruction leads to increased right ventricular pressure, causing a left-to-right shunt at the ventricular septal defect. This results in increased blood flow to the left ventricle, leading to left ventricular enlargement. The left axis deviation is due to the altered electrical axis caused by the right ventricular hypertrophy and the ventricular septal defect. The combination of left ventricular enlargement and left axis deviation is highly suggestive of TOF.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not account for the specific combination of left ventricular enlargement and left axis deviation.
**Option B:** This option is incorrect because it is not a common cyanotic heart defect associated with left ventricular enlargement and left axis deviation.
**Option C:** This option is incorrect because it does not accurately describe the characteristic features of TOF.
**Clinical Pearl / High-Yield Fact**
TOF is a classic example of a cyanotic heart defect with a characteristic "boot-shaped" cardiac silhouette on chest X-ray. This radiographic finding is a useful clinical clue for diagnosing TOF.
**Correct Answer:** C. Tetralogy of Fallot