Group A patients will be identified by no established SIHD, but presenting with symptoms consistent with myocardial ischemia; Group B patients will be idenitified by Established SIHD and symptoms of myocardial ischemia. All patients will have: (1) Indications for functional stress testing. All functional stress tests will be designed to provoke cardiac ischemia by using exercise or pharmacological stress agents; (2) Multiple (>3) cardiac risk factors including male gender, age > 50 years old, diabetes mellitus, hypertension, hyperlipidemia, nicotine exposure, and/or family history of cardiovascular disease.