A 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 tracer, is used to help show the tissue under study. In this case, the heart's chambers in motion are studied. This test can tell the doctor how well the heart pumps with each heartbeat and how much blood is pumped with each heartbeat (called the ejection fraction) both during exercise and at rest.
A radioactive tracer (usually technetium) is injected into an arm vein to "tag" blood cells so their progress through the heart can be tracked with a scanner. A special camera (called a gamma camera) then makes recordings of the heart muscle at work, like a movie. These recordings will be matched with the electrocardiogram (EKG), a recording of the heart's electrical activity.
The heart is a pump made up of specialized muscle tissue called the myocardium. The heart pumps blood throughout the body, carrying oxygen and nutrients to tissues and taking waste substances away. Like any pump, the heart needs fuel in order to work. The myocardium needs oxygen and nutrients, just like any other tissue in the body. The myocardium gets its oxygen and nutrients from the coronary arteries, which lie on the outside surface of the heart.
When the heart tissue does not get enough blood, it can’t function as well as it should. Over time, the heart muscle becomes weak due to a lack of food and oxygen.
An RNA procedure with rest and exercise is done so the doctor can assess the heart's function during exercise and compare it to how well the heart works at rest. If the heart muscle does not move in a normal way, and/or not enough blood is pumped out by the heart, it may be a sign of one or more of the following:
Reasons for your doctor to request a resting and exercise radionuclide angiogram (RNA) include:
If a screening exam (such as an electrocardiogram or EKG) suggests some type of heart disease that needs to be explored further, a resting and exercise RNA may be done.
There may be other reasons for your doctor to recommend resting and exercise RNA.
The amount of the radioactive tracer injected into your vein for the procedure is very small. So, there is no need for precautions against radiation exposure.
The injection of the radioactive tracer may cause some slight discomfort. Allergic reactions to the tracer are rare.
If you are pregnant or think you may be, tell your healthcare provider. There is risk of injury to the fetus from myocardial perfusion scan. Radiation exposure during pregnancy may lead to birth defects. If you are lactating, or breastfeeding, tell your healthcare provider due to the risk of contaminating breast milk with the radionuclide.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Certain factors may interfere with or affect the results of this test. These include, but are not limited to, the following:
A resting and exercise radionuclide angiogram (RNA) may be done on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.
Generally, a resting and exercise RNA follows this process:
Move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat for the length of the procedure.
You will be instructed to drink plenty of fluids and empty your bladder frequently for 24 to 48 hours after the test to help flush the remaining radioactive tracer from your body.
The IV site will be checked for any signs of redness or swelling. If you notice any pain, redness, and/or swelling at the IV site after you go home, tell your doctor as this may be a sign of infection or other type of reaction.
Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.
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