Radionuclide Angiography. This is a technique for visualizing the chambers and major blood vessels of the heart. It uses an injected radioactive tracer and can be performed during exercise, at rest, or with use of stress-inducing drugs. It is an excellent test for assessing the heart's pumping action and for determining the severity of coronary artery disease. It is an alternative to echocardiograms in certain situations.
 | Click the icon to see an internal view of the heart. |
Other Investigative Noninvasive Imaging Techniques
Magnetic Resonance Angiography (MRA). MRA is a very promising noninvasive imaging technique that can provide three-dimensional images of the major arteries to the heart and identify disease with high accuracy. Experts believe this approach will eventually be a good alternative to angiography.
 | Click the icon to see an image of a MRI. |
Angiography
Angiography is an invasive test. It is used for patients who show strong evidence for severe obstruction on stress and other tests, and for patients with acute coronary syndrome.
- A narrow tube is inserted into an artery, usually in the leg or arm, and then threaded up through the body to the coronary arteries.
- A dye is injected into the tube, and an x-ray records the flow of dye through the arteries.
- This process provides a map of the coronary circulation, revealing any blocked areas.
 | Click the icon to see an image of dye in the coronary artery. |
Major complications include stroke, heart attacks, and kidney damage. These risks are very low (about 0.1%), however, if the procedure is done in an experienced medical center (one that performs at least 300 of these operations every year). Allergic reactions can also occur. The procedure is expensive, and between 10 - 30% of patients who have this procedure have normal results.
Biologic Markers
When heart cells become damaged, they release different enzymes and other molecules into the blood stream. Elevated levels of such markers of heart damage in the blood or urine may help predict a heart attack in patients with severe chest pain and help determine treatment. Some of these factors include:
- Troponins. The proteins cardiac troponin T and I are released when the heart muscle is damaged. Both are proving to be among the best diagnostic indications of heart attacks. They help to identify many individuals with ACS who might otherwise be misdiagnosed.
- Creatine kinase myocardial band (CK-MB). CK-MB has been a standard marker, but the MB fraction is not as accurate as troponin levels, since elevated levels can appear in people without heart injury.
- Myoglobin. Myoglobin is a protein found in heart muscles. It is released early in the injured heart, and it may be useful in combination with CK-MB and the troponins.
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