Pericarditis's an inflammation (-itis) of the pericardium (the fibrous sac surrounding the heart). Classification Pericarditis can be classified according to the composition of the inflammatory exudate. Types include: serous purulent fibrinous caseous hemorrhagic Pericardiocentesis can be performed to permit analysis of the pericardial fluid. Acute vs. chronic Acute pericarditis's more common than chronic pericarditis, and can occur as a complication of infections, immunologic conditions,… (More on Pericarditis)