Which heart sound indicates inflammation of the pericardium?

The sound that indicates inflammation of the pericardium is a rub. Pericarditis, the inflammation of the pericardium, leads to the characteristic sound known as a pericardial friction rub. This sound results from the rubbing of the inflamed layers of the pericardium as the heart beats, creating a distinctive scratching or squeaking noise that can often be heard using a stethoscope.

This sound typically has a three-part rhythm (like the sound of walking on snow) and is best appreciated during end-inspiration when the patient breathes in deeply. In the context of heart sounds, rubs are significant because they specifically relate to pericardial conditions, setting them apart from other heart sounds that may indicate different issues. Other heart sounds like systolic and diastolic murmurs—as well as gallops—are more indicative of different cardiac problems, such as valve issues or heart failure, rather than inflammation of the pericardial sac.