Radionuclide Angiogram, Resting and Exercise
What is a resting and exercise radionuclide angiogram (RNA)?
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:
- 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
Why might I need a resting and exercise radionuclide angiogram?
Reasons for your doctor to request a resting and exercise radionuclide angiogram (RNA) include:
- Chest pain
- Shortness of breath
- Fatigue (extreme tiredness)
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.
What are the risks of a resting and exercise radionuclide angiogram?
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:
- Caffeine intake within 48 hours of the procedure
- Smoking or using any form of tobacco within 48 hours of the procedure
- Certain heart medications
How do I get ready for a resting and exercise radionuclide angiogram?
- Your doctor will explain the procedure to you and give you a chance to ask questions.
- You will be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if anything is not clear.
- Fasting (not eating or drinking) may be required before the procedure. Your doctor will give you instructions as to how long you should withhold food and/or liquids.
- If you are pregnant or think you may be, tell your doctor. Radiation exposure during pregnancy may lead to birth defects.
- If you are lactating (breastfeeding), tell your health care provider due to the risk of contaminating breast milk with the radioactive tracer.
- Tell your doctor of all medications (prescription and over-the-counter), vitamins, herbs, and supplements that you are taking.
- Tell the technologist or doctor if you are allergic to or sensitive to medications, local anesthesia, contrast dyes, iodine, or latex.
- Tell your doctor if you have a pacemaker.
- Plan to wear loose, comfortable clothing for the exercise part of the test, as well as a comfortable pair of shoes.
- Based on your medical condition, your doctor may request other specific preparation.
What happens during a resting and exercise radionuclide angiogram?
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:
- You will be asked to remove any jewelry or other objects that may interfere with the procedure.
- If you are asked to remove your clothing, you will be given a gown to wear.
- An intravenous (IV) line will be started in your hand or arm.
- You will be connected to an EKG machine with leads that stick to your skin and a blood pressure cuff will be placed on your arm.
- You will lie flat on a table in the procedure room.
- The radioactive tracer will be injected into the vein to "tag" the red blood cells. You will probably not feel anything when the tracer is given.
- As another option, a small amount of blood may be withdrawn from your vein so that it may be tagged with the tracer. The tracer will be added to the blood and will be absorbed into the red blood cells, then the blood will be returned into your vein through the IV.
- During the procedure, it will be very important for you to lie as still as possible, as any movement can affect the quality of the scan.
- The gamma camera will be positioned over you as you lie on the table and will track the progress of the tagged red blood cells through your heart.
- The gamma camera will record images of your heart as it pumps the tagged blood cells through your body.
- You may be asked to change positions during the test; however, once you have changed position, you will need to lie still without talking.
- After the resting scan is done, you will be asked to exercise on a treadmill or stationary bicycle. If you notice any discomfort, such as chest pain, dizziness, headache, shortness of breath, or extreme fatigue while exercising, you should let the technologist or doctor know right away.
- You will exercise until you have reached your target heart rate (determined by the doctor based on your age and physical condition), or until you are unable to continue due to chest pain, leg pain, severe shortness of breath, or severe fatigue (tiredness).
- Immediately after exercise, you will lie on the table while a second set of images is recorded by the gamma camera.
- Once all the heart images are done, your vital signs (heart rate, blood pressure, and respiration rate) will be monitored for a period.
- The IV line will be removed, and you will most likely be allowed to leave, unless your doctor tells you differently.
What happens after a resting and exercise radionuclide angiogram?
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.
Next stepsBefore you agree to the test or the procedure make sure you know:
- The name of the test or procedure
- The reason you are having the test or procedure
- The risks and benefits of the test or procedure
- When and where you are to have the test or procedure and who will do it
- When and how will you get the results
- How much will you have to pay for the test or procedure