What is a Nuclear Stress Test?

Cardiolite and Thallium are radioactive tracers, also called isotopes, (not contrast dye) that can be seen with a nuclear camera. By injecting very small amounts of these tracers through an IV, a nuclear camera can detect the blood flow, or lack of it, in all areas of your heart muscle.

To determine your hearts ability to respond appropriately to stress, you will either walk on a treadmill, or be given a medication. Two common medications used are persantine, which dilates the arteries around the heart, or dobutamine, which increases the heart rate.

What does it show?

Pictures taken at rest can detect the presence of a heart attack, or a scar on the heart muscle. Pictures taken after exercise show areas of your heart muscle that have decreased blood flow with exercise.

How do I prepare for this procedure?

The radioactive isotopes are expensive, and ordered especially for your examination based on your height and weight, and the time you are scheduled. Therefore, it is very important that if you need to change your scheduled appointment, you must notify our office by 4:00 p.m. the day prior to your examination, to avoid a charge for the isotope.

If you do not provide sufficient notification, you will be billed for the isotopes, since they cannot be used for anyone else. It is also important that you arrive on time, since the isotopes ordered for your procedure may not be used if you are late.

Do not eat or drink anything, including water, for 4 hours prior to your procedure. Take your usual medications, using small sips of water, unless your physician has instructed you otherwise. If you are diabetic and are scheduled for an early morning appointment, take your usual insulin dose, and have a glass of juice and a slice of dry toast for breakfast.

Do not smoke for 12 hours prior to the procedure.

Do not eat or drink any foods or take any medications that contain caffeine for 12 hours prior to the procedure, including all forms of regular and decaffeinated coffee and tea, chocolate, and cola drinks. Many medications contain caffeine, including Anacin, Darvon Cpd, Norgesic, Excedrin, Fiorinal, Esgic, NoDoz, Fioricet, Goodys Powders, Cafergot, and Wigraine. If you are unsure if something contains caffeine, ask your physician.

Wear comfortable clothes. Most women find skirts and pants more convenient than dresses. Be sure to wear comfortable walking shoes.

If you are having a persantine cardiolite procedure there are several additional instructions:

Be sure to notify our staff if you use inhalers, or medications to help with breathing, as special restrictions may apply.

Do not take any of the following medications for 48 hours (2 full days) before your procedure: Persantine, Theophylline, Elixophylline, Aminophylline, Uniphyl, Theo-Dur, Theobid, Sustaire, Slo-Bid, Bronkodyl, Quibron, Slo-Phyllin, Respbid, or Uni-Dur.

What happens during this procedure?

You will be asked remove your clothing from the waist up. Women will be provided with a gown. Prior to placing electrodes on your chest, the skin directly under the electrodes will be cleansed to remove any oils or dry skin that would interfere with clear tracings. The electrodes will then be attached to a monitor.

An IV will be started, and you will be given a small amount of thallium through the IV. After about 15 minutes, resting pictures will be taken of your heart. After these first images are completed, the exercise portion or drug administration will begin. The exercise portion of the procedure may vary as described below:

Exercise Cardiolite: You will begin walking on the treadmill. The speed and elevation of the treadmill will gradually be increased at set intervals. You will be asked to exercise as long as you can, until you are fatigued -- but not exhausted. At peak exercise, cardiolite will be administered through your IV. After 15 minutes, the second set of pictures will be taken.

Dobutamine Cardiolite: A dose of dobutamine is calculated for you based upon your height and weight. The infusion of dobutamine will begin, during which time you will be closely monitored. The rate of infusion will be increased at set intervals until you reach your peak heart rate. When the infusion is stopped, you will be given a small amount of cardiolite through your IV. After 15-30 minutes, the second set of pictures will be taken.

Persantine Cardiolite: A dose of persantine is calculated for you based upon your height and weight. After the infusion of persantine begins, your heart rate and blood pressure will be monitored for several minutes. You may be asked to walk slowly on a treadmill, or do hand-grip exercises. At peak exercise you will be given a small amount of cardiolite through your IV. After 30-60 minutes, the second set of pictures will be taken.

How long does this procedure take?

The Virginia Cardiovascular Specialists Diagnostic Center was designed to provide patients state-of-the-art diagnostic and therapeutic procedures, in an efficient and economical manner. The procedure will require about 1 1/2-2 hours, as compared to about 4 hours in a hospital setting.

Is this procedure safe?

Your study will be supervised and interpreted by a nuclear cardiologist at the Virginia Cardiovascular Specialists Diagnostic Center.

The radioactive isotopes usually do not cause allergic reactions, and will not react with any medications you may be taking. You should not feel any effects of the cardiolite or thallium injections, because very small amounts of these tracers are used and they lose their activity within hours or days, and are quickly eliminated from the body.

Any type of stress may cause potential problems in patients with heart disease, including blood pressure changes, dizziness, abnormal heart rhythms, and very rarely heart attacks. For this reason, a physician or a specially trained nuclear technician will administer your test.

If you are pregnant, suspect that you may be pregnant, or are a nursing mother, you should not have these tests.

What about the procedure results?

The results will be communicated to your physician within 24 business hours after your procedure. Your physician or nurse will then discuss the results with you.