Acute pericarditis.

There are many causes of acute pericarditis (inflammation of the pericardium) and diagnosis is often difficult owing to the dynamic nature of the disease. History and physical examination, augmented by radiographic and ECG studies, will allow the diagnosis to be made in the majority of cases. The ECG typically undergoes a four-stage evolution, and frequent reassessment of the patient is essential. Outpatient treatment is usually successful, although a subgroup of these patients require hospitalization.