What is the condition where fluid accumulation in the pericardial cavity compresses the heart and limits its ability to pump blood?

The condition characterized by fluid accumulation in the pericardial cavity that compresses the heart and limits its ability to pump blood is cardiac tamponade. In this situation, excess fluid, which can be due to several causes including trauma, infection, or cancer, exerts pressure on the heart, preventing it from fully expanding and contracting effectively. As a result, this leads to diminished cardiac output and can cause symptoms such as hypotension, tachycardia, and elevated venous pressure.

In contrast, myocarditis refers to inflammation of the heart muscle itself, typically due to viral infections, which can impair heart function but does not primarily relate to fluid accumulation in the pericardial space. Pericarditis involves inflammation of the pericardium, which can cause pain and discomfort, but does not necessarily lead to the same compressive effects as seen in cardiac tamponade. Heart failure is a broader term that describes the heart's inability to pump effectively, which can be due to various intrinsic and extrinsic factors but does not specifically refer to the condition of fluid accumulation in the pericardial cavity.