**Question:** Valsalva maneuver increases the murmur in:

A. Valsalva maneuver is a technique used to increase intrathoracic pressure, which helps in auscultation of heart sounds and evaluating heart valves. When performed properly, it involves sealing the mouth with one's hand, exhaling strongly, and then slowly and forcefully inhaling against the closed mouth.

**Core Concept:** Valsalva maneuver causes a change in intrathoracic pressure, leading to changes in heart sounds and auscultation findings. It is commonly used to evaluate heart valves and their function.

**Correct Answer:**

Correct Answer: C. Mitral regurgitation

**Why the Correct Answer is Right:** The Valsalva maneuver increases the pressure gradient between the aortic root and left atrium, causing the left atrial pressure to rise relative to aortic pressure. In cases of mitral regurgitation, the increased left atrial pressure leads to a more prominent regurgitant murmur, making it easier to auscultate.

**Why Each Wrong Option is Incorrect:**

A. Pulmonary hypertension (increased pulmonary arterial pressure) is caused by a decrease in the pressure gradient between the left atrium and lungs, making it less likely to increase the murmur.

B. Aortic stenosis is a condition where the aortic valve is narrowed, leading to increased pressure in the aorta and decreased pressure in the left ventricle. The Valsalva maneuver would decrease the pressure gradient between the left atrium and the aorta, making it less likely to increase the murmur.

C. Mitral stenosis is a condition where the mitral valve is narrowed, leading to increased pressure in the left atrium and decreased pressure in the left ventricle. The Valsalva maneuver increases the pressure gradient between the left atrium and aorta, causing a more prominent mitral regurgitant murmur, making it more likely to increase the murmur in this condition.

D. Tricuspid stenosis is a condition where the tricuspid valve is narrowed, leading to increased pressure in the right ventricle and decreased pressure in the right atrium. The Valsalva maneuver increases the pressure gradient between the right atrium and pulmonary artery, making it less likely to increase the murmur.

**Clinical Pearl:** Understanding the effect of the Valsalva maneuver on pressure gradients in different cardiac conditions can help identify the source of murmurs during physical examination.