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 test. This means that a tiny amount of a radioactive substance (called a tracer) is used to help show the tissue under study. In this test, healthcare providers study the heart's chambers in motion. This test can tell the provider how well the heart pumps and how much blood it pumps with each heartbeat both during exercise and at rest.

Your healthcare provider injects a radioactive tracer into an arm vein. This is a way to identify (tag) blood cells. This lets the provider track their progress through the heart with a scanner. A special camera (called a gamma camera) then records the heart muscle at work. Your provider can match these recordings with the electrocardiogram (ECG), a recording of the heart's electrical activity.

An RNA test with rest and exercise lets the healthcare provider assess the heart's function during exercise. The provider can then compare this to how well the heart works at rest. If the heart muscle does not move in a normal way, or not enough blood is pumped out by the heart, it may be a sign of one or more of these:

Injury to the heart muscle, possibly as a result of decreased blood flow to the heart muscle due to clogged heart arteries
An enlargement of one or more of the heart's chambers
A weak area in the heart muscle (aneurysm)
Toxic effects of certain medicines
Heart failure

Why might I need an RNA?

Your healthcare provider may request a resting and exercise RNA if you have:

Chest pain
Shortness of breath
Dizziness
Extreme tiredness (fatigue)

If a screening exam (such as an electrocardiogram or ECG) suggests some type of heart disease that needs to be looked at further, a resting and exercise RNA may be done.

There may be other reasons for your healthcare provider to advise a resting and exercise RNA.

What are the risks of an RNA?

The amount of the radioactive tracer your healthcare provider injects into your vein for the test is very small. So there is no need for safety measures 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 could be, tell your healthcare provider. There is risk of injury to the unborn baby from this test. Radiation exposure during pregnancy may lead to birth defects. Also tell your provider if you are breastfeeding. There is a risk of contaminating your breastmilk with the radioactive tracer.

There may be other risks depending on your specific health condition. Discuss any concerns with your provider before the test.

Certain factors may interfere with or affect your test results. These include:

Having caffeine within 48 hours of the test
Smoking or using any form of tobacco within 48 hours of the test
Certain heart medicines

How do I get ready for an RNA?

Your healthcare provider will explain the test and you can 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 unclear.
Follow any directions you are given about not eating or drinking before the test.
If you are pregnant or think you could be, tell your healthcare provider. Radiation exposure during pregnancy may lead to birth defects.
If you are breastfeeding, tell your healthcare provider. There is a risk of contaminating your breastmilk with the radioactive tracer.
Tell your provider all of the medicines you are taking. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. It also includes any illegal drugs.
Tell the technologist or your provider if you are allergic to or sensitive to medicines, local anesthesia, contrast dyes, iodine, or latex.
Tell your provider if you have a pacemaker or any other implanted heart devices.
Plan to wear loose, comfortable clothing for the exercise part of the test. Wear comfortable sneakers.
Based on your health condition, your provider may request other specific preparation.

What happens during an RNA?

A resting and exercise radionuclide angiogram (RNA) may be done on an outpatient basis. This means you will go home the same day. Or it may be done as part of your stay in a hospital. Steps may vary depending on your condition and your healthcare provider'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 test.
You may need to change into a hospital gown.
A healthcare professional will start an IV (intravenous) line in your hand or arm.
A nurse will connect you to an ECG machine with leads that stick to your skin. A blood pressure cuff will be placed on your arm.
You will lie flat on a table in the procedure room.
Your healthcare provider will inject the radioactive tracer into the vein to tag the red blood cells. You will likely not feel anything when the tracer is given.
As another choice, a small amount of blood may be withdrawn from your vein so it can be tagged with the tracer. The tracer will be added to the blood. It will be absorbed into the red blood cells. Then the blood will be returned into your vein through the IV line.
During the test, it will be very important for you to lie as still as possible. Any movement can affect the quality of the scan.
Your healthcare provider will position the gamma camera over you as you lie on the table. It 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. But 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 bike. If you notice any discomfort while exercising, tell the technologist or provider right away. This includes chest pain, dizziness, headache, shortness of breath, or severe tiredness.
You will exercise until you have reached your target heart rate (determined by your provider based on your age and physical condition). Or until you can't continue due to chest pain, leg pain, severe shortness of breath, or severe tiredness.
Immediately after exercise, you will lie on the table while your provider records a second set of images.
Once all the heart images are done, your vital signs (heart rate, blood pressure, and respiration rate) will be watched for a certain time.
A healthcare provider will remove the IV line. You will most likely be able to leave, unless your provider tells you differently.

What happens after an RNA?

Move slowly when getting up from the scanner table. This will help prevent any dizziness or lightheadedness from lying flat during the test.

Drink plenty of fluids and empty your bladder often for 24 to 48 hours after the test. This will help flush the remaining radioactive tracer from your body.

A nurse will check the IV site for any signs of redness or swelling. If you notice any pain, redness, or swelling at the IV site after you go home, tell your healthcare provider. This may be a sign of infection or other type of reaction.

Your provider may give you other instructions after the test, depending on your situation.