Cardiac Perfusion Scan (Exercise): About This Test

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What is it?

Heart and coronary arteries

A cardiac perfusion scan measures the amount of blood in your heart muscle at rest and after your heart has been made to work hard.

During the scan, a camera takes pictures of your heart after a radioactive tracer is injected into a vein in your arm. The tracer travels through the blood and into your heart. As the tracer moves through your heart, areas that have good blood flow absorb the tracer. Areas that do not absorb the tracer may not be getting enough blood or may have been damaged by a heart attack. The pictures show this difference.

Two sets of pictures may be made during the test. One set is taken while you are resting. Another set is taken after your heart has been made to work harder (called a stress test). The heart can be stressed by using medicine or exercise. This information is about using exercise to stress the heart.

This test is also known by other names, including myocardial perfusion scan, myocardial perfusion imaging, thallium scan, sestamibi cardiac scan, and nuclear stress test.

Why is this test done?

The test is often done to find out what may be causing chest pain or pressure. It may be done after a heart attack to see if areas of the heart are not getting enough blood or to find out how much your heart has been damaged from the heart attack.

How can you prepare for the test?

  • Do not smoke or eat a heavy meal before this test.
  • Wear flat, comfortable shoes (no bedroom slippers) and loose, lightweight shorts or sweatpants. Walking or running shoes are best.
  • Tell your doctor if:
    • You are taking any medicines.
    • You are taking medicines for an erection problem, such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra). You may need to take nitroglycerin during this test, which can cause a serious reaction if you have taken a medicine for an erection problem within the past 48 hours.
    • You have had bleeding problems, or if you take aspirin or some other blood thinner.
    • You have joint problems in your hips or legs that may make it hard for you to exercise.
    • You have a heart valve problem, such as severe aortic stenosis.
  • You are or might be pregnant.
  • You are breastfeeding. Do not breastfeed your baby for 2 days after this test. During this time, you can give your baby breast milk you stored before the test, or you can give formula. Throw out the breast milk you pump for 2 days after the test.

What happens during the test?

Resting or baseline scan

  • You will take your top off and be given a gown to wear.
  • Electrodes will be attached to your chest to keep track of your heartbeats.
  • Your arm will be cleaned. You will have a tube, called an IV, put into your arm. A small amount of the radioactive tracer will be put in the IV.
  • You will lie on your back or your stomach on a table with a large camera positioned above your chest. The camera records the tracer's signals as it moves through your blood. The camera does not produce any radiation, so you are not exposed to any additional radiation while the scan is being done.
  • You will be asked to remain very still during each scan, which takes about 5 to 10 minutes. The camera will move to take more pictures at different angles. Several scans will be taken.

This test takes about 30 to 40 minutes.

Stress scan using exercise

The stress scan is done in two parts. In many hospitals, you first have the resting scan. You then exercise to make your heart work harder and you have another scan. Sometimes the stress scan is done first.

You most likely will either walk on a treadmill or pedal a stationary bicycle. During this test:

  • Your heart rate and blood pressure are recorded.
  • You might be asked to use numbers to say how hard you are exercising. The higher the number, the harder you think you are exercising.
  • You will continue to exercise until you or your doctor feels you need to stop.

You will then have another resting scan. See the "Resting or baseline scan" section.

If a resting scan had not been done before the exercise scan, you may be asked to return to get this scan on another day or a few hours later.

What else should you know about the test?

  • No electricity passes through your body during the test. There is no danger of getting an electrical shock.
  • This test involves exposure to radiation, but the benefit of the testing far outweighs the slight risk of radiation exposure.
  • During the tests, tell your doctor if:
    • You have chest pain or pressure.
    • You are very short of breath.
    • You are light-headed.
    • You have other symptoms.

What happens after the test?

  • You will be able to sit or lie down and rest.
  • Your heart rate and blood pressure will be checked for about 5 to 10 minutes.
  • You can go back to your usual activities right away.
  • Drink plenty of fluids for the next 24 hours to help flush the tracer out of your body. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.
  • If you are breastfeeding, you will need to use saved breast milk or formula for 2 days after the test. This is so you won't pass the tracer to your baby.

When should you call for help?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness).
  • You have been diagnosed with angina, and you have angina symptoms that do not go away with rest or are not getting better within 5 minutes after you take a dose of nitroglycerin.
  • You have symptoms of a heart attack. These may include:
    • Chest pain or pressure, or a strange feeling in the chest.
    • Sweating.
    • Shortness of breath.
    • Nausea or vomiting.
    • Pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly or in one or both shoulders or arms.
    • Light-headedness or sudden weakness.
    • A fast or irregular heartbeat.
    After you call 911, the operator may tell you to chew 1 adult-strength or 2 to 4 low-dose aspirin. Wait for an ambulance. Do not try to drive yourself.

Call your doctor or nurse call line now or seek immediate medical care if:

  • You have had any angina symptoms, such as chest pain or pressure, even if they have gone away.
  • You have new or increased shortness of breath.
  • You are dizzy or light-headed, or you feel like you may faint.

Watch closely for changes in your health, and be sure to contact your doctor or nurse call line if you have any problems.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

Go to http://www.healthwise.net/ed

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