Selected patients will undergo a CPET evaluation. The initial CPET will identify patients with underlying ischemia and serve as a baseline study. Ischemia will be assessed using: 1) peak VO2: measures the peak transport of O2 to the tissues when O2 extraction from the blood is maximal; 2) the anaerobic threshold (AT): measures the sustainable work capacity in units of VO2; 3) the O2-pulse measurements at the AT peak VO2: estimate stroke volume at those levels of exercise; and 4) the relationship of O2 uptake to work rate (ΔVO2/ΔWR): provides information on the ability of the cardiac output to increase. Patients whoseCPET results meet the criteria for ischemia will be started on Ranexa 500mg BID and advanced within one week +/-4 days to 1000mg BID. A second CPET will be performed after 4 weeks +/- 4 days of maximum therapy. CPET results before and after therapy will undergo a statistical comparison. The initial off treatment CPET measurement will serve as the control to assess changes found during therapy. No medication changes or revascularization procedures will occur during the study. If patients require and undergo a medication change or a revascularization procedure, they will be excluded from the study.