Two thin membranes enclose the heart in a sack-like structure. If these membranes become irritated or inflamed, the condition is known as pericarditis. Pericarditis is fairly common, affecting about 1 in 1,000 people at some point in their lives. It can be caused by flu, polio, injury, or German measles. Other causes are rheumatoid arthritis or lupus,Ê and this condition sometimes follows a heart attack.
Inflammation of the pericardium. Among the causes of pericarditis are viral infection and cancer. Pericarditis can results in fever, chest pain, and the build-up of too much fluid in the sac, known as pericardial effusions. Rarely, the pericardium thickens in chronic constrictive pericarditis, interfering with the functioning of the heart.