In High Thoracic Epidural Anesthesia (HTEA) the use of a local anesthetic (LA) with low cardiac toxicity is crucial as myocardial contractility is often already seriously impaired. The aim of this study is to compare the efficacy, doses and side effects of ropivacaine and levobupivacaine in patients submitted to coronary artery bypass graft with HTEA and general anesthesia. The primary end point is the amount of LA drug required to maintain a VAS < 4 when coughing in the first 24 postoperative hours.