What is a resting radionuclide angiogram?

Resting radionuclide angiogram (RNA) is a type of nuclear medicine test. Doctors use a tiny amount of a radioactive substance, called a tracer, during the scan to help show the heart’s chambers in motion. This test can tell the doctor how well the heart pumps and how much blood is pumped with each heartbeat. This is called the ejection fraction.

Your doctor injects a radioactive tracer (usually technetium) into an arm vein. The tracer “tags" blood cells so your doctor can track them with a scanner as they move through the heart. A special camera (called a gamma camera) then records the heart muscle at work, like a movie. Your doctor can match these recordings with the electrocardiogram (ECG). An ECG is a recording of the heart's electrical activity.

If the heart muscle doesn’t move normally, 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 heart arteries

• An enlargement of one or more of the heart's chambers

• Aneurysm (a weak area in the heart muscle)

• Toxic effects of certain medicines

• Heart failure

Why might I need an RNA?

Reasons for your doctor to request a resting radionuclide angiogram (RNA) include:

• Chest pain

• Shortness of breath

• Dizziness

• Fatigue (extreme tiredness)

If your doctor thinks you have some type of heart disease, a resting RNA may be done.

There may be other reasons for your doctor to recommend this test.

What are the risks of an RNA?

Your doctor uses only a small amount of the radioactive tracer. So, there is no need for precautions against radiation exposure.

The injection of the radioactive tracer may cause some sight discomfort. Allergic reactions to the tracer are rare.

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 may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor before the procedure.

Certain factors may interfere with or affect the results of this test. These include:

• Caffeine intake before the procedure

• Smoking or using any form of tobacco before the procedure

• Certain heart medicines

How do I prepare for an RNA?

• Your doctor 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.

• Generally, you won't need sedation. You may be told to fast (not eat or drink) for at least 3 to 4 hours before the test.

• You may need to restrict tobacco and caffeine 2 or 3 hours before testing.

• If you are pregnant or think you could be, tell your doctor. Radiation exposure during pregnancy may lead to birth defects.

• If you are breastfeeding, tell your healthcare provider. There is a risk of contaminating breast milk with the radioactive tracer.

• Tell your doctor of all medicines (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 medicines, local anesthesia, contrast dyes, iodine, or latex.

• Tell your doctor if you have a pacemaker or any other implanted cardiac devices.

• Based on your medical condition, your doctor may request other specific preparation.

What happens during an RNA?

A resting radionuclide angiogram (RNA) may be done on an outpatient basis or as part of your stay in a hospital. Steps may vary depending on your condition and your doctor's practices.

Generally, a resting 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 intravenous (IV) line in your hand or arm.

• A healthcare professional will connect you to an ECG machine with leads that stick to your skin and place a blood pressure cuff on your arm.

• You will lie flat on a table in the procedure room.

• Your doctor will inject the radioactive tracer into the IV 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 can 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 test, it will be very important for you to lie as still as possible, as any movement can affect the quality of the scan.

• Your doctor will position the gamma camera over you as you lie on the table. It 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 scan is done, the IV line will be removed, and you can leave, unless your doctor tells you differently.

What happens after an RNA?

Be sure to move slowly when getting up from the scanner table to avoid any dizziness or lightheadedness from lying flat for the length of the test.

Drink plenty of fluids and empty your bladder often for 24 to 48 hours after the test to 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 doctor as this may be a sign of infection or other type of reaction.

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