Commonest cause of heart failure in infancy is –
**Core Concept**
Heart failure in infancy is a severe condition that can be caused by various factors, including congenital heart defects, infections, and metabolic disorders. The commonest cause of heart failure in infancy is often related to structural anomalies of the heart that are present at birth.
**Why the Correct Answer is Right**
The commonest cause of heart failure in infancy is typically a congenital heart defect, specifically a large ventricular septal defect (VSD). A VSD is a hole in the wall between the two ventricles, allowing blood to flow from the left to the right ventricle. This leads to excessive blood flow to the lungs, causing pulmonary overcirculation and subsequent heart failure. The increased workload on the heart can cause left ventricular hypertrophy and eventually lead to heart failure.
**Why Each Wrong Option is Incorrect**
**Option A:** Hypoplastic left heart syndrome is a rare congenital heart defect, accounting for less than 5% of cases of heart failure in infancy.
**Option B:** Cardiac tamponade is a life-threatening condition where fluid accumulates in the pericardial sac, compressing the heart. While it can cause heart failure, it is less common than VSD in infancy.
**Option C:** Coarctation of the aorta is a narrowing of the aorta that can cause hypertension and heart failure, but it is less common than VSD in infancy.
**Clinical Pearl / High-Yield Fact**
The most common congenital heart defect in infancy is a ventricular septal defect (VSD), and it is often associated with a biventricular heart.
**Correct Answer: A. Ventricular Septal Defect**