Resting and exercise radionuclide angiogram (RNA) is a type of nuclear medicine procedure. This means that a tiny amount of a radioactive substance, called a radionuclide (radiopharmaceutical or radioactive tracer), is used during the procedure to assist in the examination of the tissue under study. Specifically, resting RNA evaluates the heart's chambers in motion.
A radionuclide (usually technetium) will be injected into an arm vein to "tag" the blood cells so their progress through the heart can be traced with a scanner. A special camera (gamma camera) will make recordings of the heart wall at work, like a motion picture. These recordings will be synchronized with the heartbeat by using the electrocardiogram (ECG, or recording of the heart's electrical activity).
A doctor specially trained in nuclear cardiology will study the films to evaluate the heart's pumping function and ejection fraction (the volume of blood pumped out with each heartbeat).
An RNA procedure with rest and exercise is performed to assist the doctor in assessing the heart's function during exercise after comparing it to the heart's function at rest. If the heart muscle does not move in a normal manner, and/or a less-than-normal amount of blood is pumped out by the heart, this may indicate one or more of the following:
- Injury to the heart muscle, possibly as a result of decreased blood flow to heart muscle due to clogged coronary arteries
- An enlargement of one or more of the heart's chambers
- Aneurysm (a weak area in the heart muscle)
- Toxic effects of certain medications
Other related procedures that may be used to assess the heart include resting or exercise electrocardiogram (ECG or EKG), Holter monitor, signal-averaged ECG, cardiac catheterization, chest X-ray, computed tomography (CT scan) of the chest, echocardiography, electrophysiological studies, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, and cardiac CT scan. Please see these procedures for additional information.
If a screening examination (such as an ECG) suggests a possibility of some type of heart disease process that needs to be explored further, a resting and exercise RNA may be performed.
There may be other reasons for your doctor to recommend resting and exercise RNA.
The amount of the radionuclide injected into your vein for the procedure is small enough that there is no need for precautions against radioactive exposure. The injection of the radionuclide may cause some slight discomfort. Allergic reactions to the radionuclide are rare.
If you are pregnant or suspect that you may be pregnant, you should notify your health care provider due to the risk of injury to the fetus from radionuclide angiography. Radiation exposure during pregnancy may lead to birth defects. If you are lactating, or breastfeeding, you should notify your health care provider due to the risk of contaminating breast milk with the radionuclide.
Patients who are allergic to or sensitive to medications, contrast dyes, iodine, tape, or latex should notify their doctor.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Nicotine in cigarettes may cause spasm in the coronary arteries, which could affect the test results.