Earliest sign of left atrial enlargement is –
**Core Concept**
Left atrial enlargement is a condition where the left atrium of the heart becomes dilated or enlarged, often due to increased pressure or volume overload. This can be a sign of underlying cardiac pathology, such as mitral stenosis or heart failure.
**Why the Correct Answer is Right**
The earliest sign of left atrial enlargement is the **widening of the left atrial appendage**. As the left atrium dilates, the appendage, which is a small pouch-like structure attached to the left atrium, also becomes enlarged. This is due to the increased pressure and volume within the left atrium, which causes the appendage to stretch and become visible on imaging studies, such as chest X-rays or echocardiograms.
**Why Each Wrong Option is Incorrect**
**Option A:** The **left ventricular hypertrophy** is not an early sign of left atrial enlargement, but rather a sign of left ventricular overload, which can occur in response to left atrial enlargement.
**Option B:** The **pulmonary venous redistribution** is a sign of left atrial enlargement, but it is not the earliest sign. It occurs when the left atrium becomes enlarged and pushes the pulmonary veins upwards, causing them to become more prominent on imaging studies.
**Option C:** The **E point on the jugular venous pulse** is not a direct sign of left atrial enlargement. The E point is a sign of increased right atrial pressure, which can occur in response to left atrial enlargement, but it is not a specific indicator of left atrial size.
**Clinical Pearl / High-Yield Fact**
In patients with left atrial enlargement, the left atrial appendage is often the first structure to become enlarged, making it an important landmark for diagnosing this condition.
**Correct Answer: B. Pulmonary venous redistribution.**