What are the most common conditions that are treated by pericardiocentesis?

Pericarditis: Pweicardiocentesis is utilized for removing fluid in the pericardial sac when the fluid is pressing on the heart and restricting flow. The fluid is analyzed to find the cause thus future treatment of the fluid.

Only 2: There are only 2 reasons to do pericardiocentesis: to relieve tamponade and to diagnose fluid by retrieving some for the lab. Conditions that cause pericardial effusion are: trauma (e.g. Blood), infection (e.g. Tb or viral), malignancy (e.g. Breast or lung cancer), thyroid deficiency, uremia, collagen vascular disease (e.g. Lupus). This is not a complete list but covers the most common causes.