Pericardium in a sentence as a noun

The linked Wikipedia article considers the substance that organs rest on, such as the pericardium, to be part of the fascia system.

This is generally curable by surgery to remove your pericardium.

Maybe the OP has the heart sounds confused with a pericardial friction rub, which can happen in pathological states and is due to the heart sliding against the pericardium.

Pericardium definitions

noun

a serous membrane with two layers that surrounds the heart