What clinical finding is indicative of acute pericarditis?

The presence of a pericardial friction rub is a classic clinical finding indicative of acute pericarditis. This sound is produced when the inflamed pericardial layers rub against each other during the cardiac cycle, particularly during ventricular systole and diastole. Characteristically, the friction rub is a high-pitched, scratchy sound that can be auscultated best at the left lower sternal border, often described as having a triphasic quality that coincides with heartbeats.

In the context of acute pericarditis, this finding helps differentiate it from other causes of chest pain; it is relatively specific to the condition. The distinguishing feature of a pericardial friction rub is its reproducibility, meaning that it can change with position or breath, often becoming less audible or more pronounced. This feature helps clinicians establish a diagnosis and guides further evaluation and management of the patient.

Other options, like heart murmurs and high blood pressure, are more nonspecific or related to other cardiovascular conditions. Echogenic fluid in the pericardium suggests the presence of pericardial effusion rather than directly indicating acute pericarditis. While effusion can occur in the context of acute pericarditis, the