depending on the time of presentation and duration, pericarditis is divided into "acute" and "chronic" forms. acute pericarditis is more common than chronic pericarditis, and can occur as a complication of infections, immunologic conditions, or even as a result of a heart attack (myocardial infarction), as dressler's syndrome. chronic pericarditis however is less common, a form of which is constrictive pericarditis. the following is the clinical classification of acute vs. chronic: