## **Core Concept**
The question describes a 9-month-old child of a diabetic mother presenting with tachypnea and hepatomegaly. The echocardiography shows normal cardiac morphology with asymmetric septal hypertrophy. This clinical presentation suggests the child has **asymmetric septal hypertrophy (ASH)**, a form of **hypertrophic cardiomyopathy (HCM)**, which can be associated with maternal diabetes.

## **Why the Correct Answer is Right**
The correct answer, Propranolol, is a **beta-blocker** that is commonly used to treat **hypertrophic cardiomyopathy (HCM)**, particularly in cases with asymmetric septal hypertrophy. Propranolol works by reducing the heart rate and contractility, which decreases the obstruction to outflow and improves symptoms. In the context of a child with HCM and asymmetric septal hypertrophy, propranolol is beneficial as it helps in managing symptoms such as tachypnea and potentially reduces the risk of complications.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Digoxin is a cardiac glycoside that increases the force of cardiac contractions and slows the heart rate. It is not suitable for treating HCM as it can worsen the obstruction to outflow by increasing contractility.
- **Option B:** Furosemide is a loop diuretic used to treat fluid overload conditions such as heart failure. While the child has hepatomegaly suggesting possible congestion, the primary issue here is HCM with asymmetric septal hypertrophy, not heart failure requiring diuresis.
- **Option C:** Lisinopril is an ACE inhibitor used primarily to treat hypertension and heart failure. ACE inhibitors can be harmful in HCM as they may decrease the left ventricular outflow tract gradient but can also reduce the contractility of the heart and potentially worsen symptoms.

## **Clinical Pearl / High-Yield Fact**
In children with **hypertrophic cardiomyopathy (HCM)**, particularly those with asymmetric septal hypertrophy, **beta-blockers** like propranolol are first-line treatments to manage symptoms and prevent complications. It's crucial to monitor these patients closely for signs of worsening obstruction or heart failure.

## **Correct Answer:** . Propranolol