This study was suspended by principal investigator's decision. All the sites were not opened, and the recruitment was so slow.

Treatment of pericarditis largely remains empirical due to the relative lack of randomized controlled trials. Nevertheless, some recommendations have been formulated to guide management and follow-up of acute pericarditis. Aspirin or an NSAID at medium to high dosages is the mainstay of treatment. Optimal length of treatment is not established.

PERICARDITE is a French multicentric placebo controlled double blind randomized trial assessing efficacy of a brief treatment based on Aspirin (4 days) versus a longer treatment (21days) in treating a first episode of probably idiopathic acute pericarditis. It is a non inferiority trial.

Exclusion criteria are: diseases known to cause pericarditis: (recent myocardial infarction, autoimmune disease, postpericardiotomy syndromes, connective tissue disease, tuberculosis, neoplastic disease).

Primary endpoint is: 30 days recovery defined as the normalization of all clinical and paraclinical initial abnormalities.

Secondary endpoint is: 6-month recurrence.

Inclusion Criteria:

• age over 18
• first episode of acute pericarditis
• chest pain lasting less than 24 hours

Exclusion Criteria:

• contraindication to aspirin
• previous history of atypical chest pain
• previous history of connective tissue disease, tuberculosis, recent MI, auto immune disease, neoplastic disease, thoracic trauma, previous thoracic surgery, antiplatelet routine treatment, anticoagulation