Background: The incidence of asymptomatic pericardial effusion is high after cardiac surgery.

Objective: To assess whether colchicine is effective in reducing post operative pericardial effusion volume.

Design: Multicenter, randomized, double-blind, placebo-controlled study. Intervention : colchicine 1mg vs placebo, once daily for 14 days Setting :10 post operative cardiac rehabilitation centers. Patients: 200 patients at high risk of tamponade because of moderate to large persistent pericardial effusion (grade 2, 3 or 4 on a scale of 0 to 4 measured by echocardiography) more than 7 days after cardiac surgery.

Measurements: The main end point will be change in effusion grade after 14 days of treatment. Secondary endpoints include frequency of late cardiac tamponade.

Clinically insignificant pericardial effusion is common after heart surgery with an incidence of 50 % to 85 % a few days after surgery Cardiac tamponade occurs in about 1-2 % of patients who undergo cardiac surgery and may develop slowly without clear-cut clinical signs. Most tamponade occurs more than 7 days after surgery which is a concern because, at that time, patients often have already been discharged from the hospital.

No study has ever shown the efficacy any drug for this condition.In particular, we published a study demonstrating the absence of efficacy of a non steroidal anti inflammatory drug (Meurin P, Tabet JY, Thabut G, et al.French Society of Cardiology. Nonsteroidal anti-inflammatory drug treatment for postoperative pericardial effusion: a multicenter randomized, double-blind trial. Ann Intern Med. 2010 Feb2;152(3):137-43) Cochicine is widely used to treat inflammatory pericarditis ; is it efficient to treat post operative pericardial effusions ? this is the question we want to answer to.

Design: Multicenter, randomized, double-blind, placebo-controlled study. Intervention : colchicine 1mg vs placebo, once daily for 14 days Setting :10 post operative cardiac rehabilitation centers. Patients: 200 patients at high risk of tamponade because of moderate to large persistent pericardial effusion (grade 2, 3 or 4 on a scale of 0 to 4 measured by echocardiography) more than 7 days after cardiac surgery.

Measurements: The main end point will be change in effusion grade after 14 days of treatment. Secondary endpoints include frequency of late cardiac tamponade.

Inclusion Criteria:

• patients with recent cardiac surgery
• admitted for cardiac rehabilitation
• pericardial effusion > grade 2 (corresponds to a loculated effusion > 10 millimeters or a circumferential effusion of any size)on the first trans thoracic echocardiography performed more than 7 days after surgery

Exclusion Criteria:

• patients who do not give written consent to participate
• pregnancy
• colchicine allergy;
• renal failure, which we define as a serum creatinine level > 250micromol/l or clairance < 30 ml/mn
• heart transplantation,or correction of congenital heart anomalies cardiac surgery more than 30 days before their first trans thoracic echocardiography pericardial effusion that requires immediate drainage.