Background:

• Noninvasive cardiac stress testing is imperfect. Inconclusive test results generate further expensive testing.
• In patients with known or suspected coronary artery disease, both computed tomography (CT) and magnetic resonance imaging (MRI) have been shown to provide suitable results for detecting the disease. However, both types of scans have limitations in their usefulness, and it is not known whether one is preferable in either accuracy or cost-effectiveness.

Objectives:

- To determine the accuracy and cost-effectiveness of CT and MRI in subjects with a prior inconclusive heart stress test.

Eligibility:

- Patients 18 years of age and older who have had an inconclusive heart stress test within the past 90 days.

Design:

• A blood test will be obtained prior to both heart tests. This will require less than a teaspoon of blood.
• A CT scan will be performed, accompanied by beta blocker medications (to slow heart rate) or nitroglycerin (to enlarge blood vessels) to improve picture quality, as needed.
• An MRI scan will be performed. Scans will be taken before, during, and after the patient receives vasodilators (to increase blood flow to the coronary arteries and detect blockages in heart blood vessels).
• Heart rate and function will be monitored with an electrocardiogram.

Noninvasive cardiac stress testing is imperfect. Inconclusive test results generate further expensive testing. We will do both cardiac computed tomography (CT) and stress cardiac magnetic resonance imaging (MRI) in patients who have an inconclusive noninvasive cardiac stress test. We will test whether MRI predicts significant coronary artery disease in a more cost-effective and accurate manner than CT, or vice versa.

• GENERAL INCLUSION CRITERIA:
• 18 years of age and older
• Prior equivocal stress study within the preceding 90 days
• Able to provide informed consent

MEDICAL EXCLUSION CRITERIA:

• Decompensated heart failure (unable to lie flat during MRI or CT)
• Severe kidney disease (MDRD estimated Glomerular Filtration Rate less than 30mL/min/1.73m(2).
• Prior cardiac revascularization with coronary stent or bypass surgery
• Resting tachycardia (HR greater than l00 bpm)
• Pregnant women (when uncertain, subjects will undergo urine or blood testing)
• Lactating women (unless they are willing to discard breast milk for 24 hours after receiving gadolinium)
• Second (Type II) and third degree atrioventricular heart block
• Asthma or chronic pulmonary disease (emphysema) actively treated with bronchodilators or leukotriene antagonists

MRI EXCLUSION CRITERIA:

• Cardiac pacemaker or implantable defibrillator
• Cerebral aneurysm clip
• Neural stimulator (e.g. TENS-Unit)
• Any type of ear implant
• Ocular foreign body (e.g. metal shavings)
• Any implanted device (e.g. insulin pump, drug infusion device)
• Metal shrapnel or bullet

This trial will involve the NIH Clinical Center and Suburban Hospital. Subjects with an equivocal stress study determined by a referring physician will be recruited from the surrounding community.