The pericardium is the sac that surrounds the heart. Pericardial disease refers to any condition that affects the pericardium, such as inflammation of the pericardium (pericarditis), excess fluid around the heart (pericardial effusion), or thickening and scarring of the pericardium (constrictive pericarditis). Common causes of pericardial disease include viral or bacterial infections, cancer, kidney failure, chest trauma, and certain autoimmune diseases.