Magnetic Resonance Imaging of the Blood Vessels of the Heart

* INCLUSION CRITERIA: Inclusion Criteria for All Arms of the Protocol 1. Known or suspected cardiovascular disease. 2. 18 years of age and older. 3. Able to provide informed consent. Exclusion Criteria for All Arms of the Protocol: Patients with a contraindication to MRI scanning will be excluded. These contraindications include patients with the following devices: 1. Central nervous system aneurysm clips 2. Implanted neural stimulator 3. Implanted cardiac pacemaker or defibrillator 4. Cochlear implant 5. Ocular foreign body (e.g. metal shavings) 6. Implanted insulin pump 7. Metal shrapnel or bullet. In addition the following patient groups will be excluded: 1. Pregnant women (Patients who are uncertain as to whether they are pregnant will be required to have a screening urine or blood pregnancy test) 2. Patients with symptoms of myocardial ischemia occurring despite maximally tolerated doses of oral antianginal therapy and intravenous nitroglycerin Furthermore, the following patient groups will be excluded from studies involving the administration of MRI contrast agents: 1. lactating women unless they are willing to discard breast milk for 24 hours 2. renal disease (estimated glomerular filtration rate \[eGFR\] less than 30 ml/min/1.73 m(2) body surface area) The eGFR will be used to estimate renal function if reported by the laboratory. Otherwise, estimated glomerular filtration rate (eGFR) can be based on the Modification of Diet in Renal Disease (MDRD) study equation (see below) in subjects with stable renal function. This formula is not applicable to patients with acute renal insufficiency: eGFR (ml/min/l.73 m(2))= 175 x (serum creatinine)-l.l54 x (age)-0.203 x 0.742 (if the subject is female) x 1.212 (if the subject is black) Additional Exclusion Criteria for Dobutamine MRI 1. Myocardial infarction within 48 hours. 2. Uncontrolled heart failure 3. Severe hypertension (SBP greater than 200, DBP greater than 110) 4. Atrial fibrillation 5. Ventricular tachycardia 6. Frequent PVC's (more than 1 every 10 heart beats or nonsustained ventricular tachycardia (greater than 4) 7. Patients with narrow angle glaucoma or known or suspected severe bladder outlet obstruction due to prostatic hypertrophy will not receive atropine Additional Exclusion Criteria for Vasodilator Stress MRI 1. Myocardial infarction within 48 hours. 2. Patients that are not considered medically stable by their physician (for example, severe heart failure that makes it difficult to breathe while lying flat or severe problems with heart rhythms). 3. Patients with 2nd or 3rd degree heart block are excluded from receiving the medicine adenosine (abnormalities that can be seen on your ECG).