Hemodynamically significant valvular disorders, history of significant coronary obstruction (greater than 50% in any single artery), angina symptoms, myocardial ischemia on an imaging stress test or evidence of prior myocardial infarction. Patients older than 40 years of age with effort induced anginal symptoms typical of coronary insufficiency and a coronary distribution of myocardial ischemia on an imaging stress test will be considered for the study if coronary angiography rules out significant obstructive coronary disease.