Working hypothesis and aims: 1) To explore the pathophysiology of postoperative troponin elevations and 2) whether ranolazine, a new anti-ischemic drug that has no effect on blood pressure or heart rate, prevents postoperative myocardial injury.

High-risk patients undergoing non cardiac surgery will be randomized to receive either Ranolazine or placebo perioperatively and troponin will be measured on the first 3 days after surgery.

Inclusion Criteria:

- All patients age 18 and above, undergoing major surgery that require at least 24 hours (overnight) stay in the post anesthesia care unit (PACU) or intensive care unit (ICU), and who either have known history of CAD or at least 3 of the following Revised Cardiac Risk Index (RCRI) criteria29F17: 1) high-risk type of surgery, 2) history of ischemic heart disease, 3) history of congestive heart failure, 4) history of cerebrovascular disease, 5) diabetes mellitus, 6) renal failure (creatinine > 2mg/ml).

Exclusion Criteria:

• Pregnancy, LV ejection fraction ≤35%, patients with severe valvular disease, patients with poor echocardiographic images, patients who cannot swallow the pill after surgery, refusal to participate