Inclusion Criteria:  Patients who undergo scheduled cardiac surgery with sternotomy for aortic or mitral valve replacement either by biological or mechanical prothesis, coronary arterial bypass surgery (CABG). Body Mass Index between 18,5 and 33kg/m² (extremity excluded) Patients who have given their consent according to the methods described in Title II of the book of the first Public Health Code Possession of Social Security insurance  Exclusion Criteria:  Emergency surgery Approach by thoracotomy Heart transplant Aortic dissection or chirurgical act on ascending thoracic Aorta Redo surgery. Pregnant women Protected minors or adults Pre-existing psychiatric pathology including known states of opioid addiction Long-term opioid medication (>1month) Physical or intellectual inability to use a PCA Severe heart failure (ejection fraction less than 40% or PAH > 50 mmHg) Preoperative cardiogenic shock Severe preoperative chronic or acute renal failure with a creatinine clearance of less than 30 mL / min according to Cockroft's formula Known allergy or hypersensitivity to any of the study drugs or analgesia protocol (ropivacaine, paracetamol, opiates). Known allergy or hypersensitivity to any of excipients of the study drugs or analgesia protocol Refusal of the protocol