Recent developments have led to the recognition of the previously unknown conditions of myocardial "stunning" and "hibernation." These condiitons can easily be mistaken for total infarction. Because viable myocardium could be salvaged, it is important to distinguish between viable and infarcted myocardium. Viability information is key when deciding to treat the patient interventionally, surgically, or medically. The ability to assess myocardial viability would be very useful in guiding treatment strategy and predicting outcome in many clinical situations such as: a) Determination of salvageable myocardium following acute myocardial infarction, b) Evaluation of myocardial viability before and after open heart surgery, and c) Detection of rejection myocardium following transplants.The specific aims of Phase I are to: 1. Investigate in a controlled myocardial model the feasibility of detection and modulation of a viability signal from normal, ischemic, and infarcted myocardium.2. Design and construct a prototype fiberoptic catheter capable of delivering to the myocardium means for triggering tissue response.3. Demonstrate the feasibility of fiberoptic transmission from the myocardium of the viability signal.The long-term objective is to develop a proprietary fiberoptic delivery system and minimally invasive test method for direct measurement of the viability of the non-contracting segments of the heart. The proposed system promises to be simple to use, accurate, and cost-effective, consequently, this technology could represent a very significant advancement in the diagnosis and treatment of heart disease.Proposed commercial application:The proposed Viability Monitoring device has the potential to become a standard diagnostic product for treatment selection and decision making. Viability monitoring promises cost effective means for providing complete myocardial status information in a timely fashion without requiring a substantial behavioral change from interventional cardiologists. The worldwide market for this product could exceed 650 million dollars annually, and the savings to the health care system could exceed 800 million dollars per year.National Institute of Heart, Lung, and Blood Institute (NHLBI)