What is the most likely physical examination finding in a patient with acute pericarditis presenting with chest pain?

In a patient with acute pericarditis, the most characteristic physical examination finding is a pericardial friction rub. This sound is produced by the inflammation of the pericardial layers rubbing against each other during the cardiac cycle. The friction rub is typically best heard with the patient sitting up and leaning forward, and it is described as a high-pitched, scratchy sound that may have multiple components, similar to the sound of leather being rubbed together.

This finding is particularly significant in acute pericarditis because it reflects the pathophysiological process of pericardial inflammation, which distinguishes it from other causes of chest pain. Other examination findings in acute pericarditis may include signs of cardiac effusion or dynamic changes in heart sounds, but the pericardial friction rub is the most specific and classic finding associated with this condition.

The other options present findings that do not typically correlate with acute pericarditis. Elevated blood pressure might occur in a variety of conditions but is not a specific finding for pericarditis. Subungual hematoma is more indicative of trauma or other systemic issues and does not relate to the heart. A diastolic murmur could suggest valvular heart disease or other cardiovascular