**Question:** A young patient presents with a systolic murmur at the apex. The murmur increases on both handgrip and Valsalva maneuver. Which of the following conditions is most likely?

A. Pulmonary artery hypertension
B. Mitral stenosis
C. Mitral regurgitation
D. Right ventricular hypertrophy

**Correct Answer:**

**Core Concept:**

Systolic murmurs at the base or apex of the heart are often indicative of valvular heart disease. The Valsalva maneuver and handgrip test are used to evaluate the effect of increased cardiac output on the murmur intensity, as they cause a temporary increase in blood pressure and cardiac output.

**Why the Correct Answer is Right:**

A systolic murmur at the apex and its response to Valsalva and handgrip tests are suggestive of conditions that cause increased cardiac output and pulmonary artery pressure, such as:

1. Pulmonary artery hypertension (PAH): This is characterized by elevated pulmonary artery pressure due to increased pulmonary vascular resistance and right ventricular hypertrophy. The Valsalva maneuver increases cardiac output and pulmonary artery pressure, making this condition relevant.
2. Right ventricular hypertrophy (RVH): This occurs as a compensatory response to increased afterload, leading to increased cardiac output and elevated pulmonary artery pressure. The Valsalva maneuver and handgrip tests exacerbate the murmur in patients with RVH.

**Why Each Wrong Option is Incorrect:**

3. Mitral stenosis (MS): A mitral stenosis results in a mitral valve narrowing, causing low cardiac output and a diastolic murmur. The Valsalva maneuver and handgrip tests would decrease the murmur intensity, not increase it.
4. Mitral regurgitation (MR): Mitral regurgitation leads to a diastolic murmur due to backflow of blood through the mitral valve. Applying Valsalva maneuver and handgrip tests would also decrease the murmur intensity, similar to MS.

**Clinical Pearls:**

1. A systolic murmur at the apex, worsening Valsalva and handgrip tests, is a strong indicator of increased cardiac output and pulmonary artery pressure, such as in PAH or RVH.
2. The Valsalva maneuver and handgrip tests are used to evaluate the effect of increased cardiac output on the murmur intensity and can help differentiate between increased pulmonary artery pressure (e.g., PAH or RVH) and decreased cardiac output (e.g., MS or MR).
3. In this case, the patient's murmur worsens (increases) with Valsalva and handgrip tests, indicating increased cardiac output and elevated pulmonary artery pressure, which is consistent with PAH or RVH.