In addition, patients will be asked to undergo a non-invasive test called Peripheral Arterial Tonometry or PAT for research purposes and in some cases, if clinically indicated a Cardiac Magnetic Resonance (CMR) imaging test as a standard of care. Patients will be followed up using phone questionnaires at 6 months and than annually thereafter. It is proposed that problems with the function of the large and small arteries may be responsible for giving some patients their symptoms of chest pain and put them at risk for heart attacks. PAT may help us more easily and non-invasively measure this function by testing the arteries in the arm. Selected patients will also undergo CMR imaging that may be useful to detect abnormalities in the inner layer of the heart muscle resulting from the abnormal function of the large and small heart arteries. These non-invasive tests will be corroborated with results from invasive testing during heart catheterization, which is considered the gold standard for testing for function of the large and the small heart arteries.