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Cardiac Perfusion Scan (Medicine): About This Test

Heart and coronary arteries

What is it?

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. Either medicine or exercise can be used to stress the heart. This information is about using medicine for this test.

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 don't 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).

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 do you prepare for the test?

Tell your doctor ALL the medicines and natural health products you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.

If you take aspirin or some other blood thinner, ask your doctor if you should stop taking it before your test. Make sure that you understand exactly what your doctor wants you to do. These medicines increase the risk of bleeding.

Tell your doctor if you are taking any erection-enhancing medicines (such as Cialis, Levitra, or Viagra). You may need to take nitroglycerin during this test, which can cause a serious reaction if you have taken an erection-enhancing medicine within the previous 48 hours.

Do not have any caffeine, such as coffee or tea, for 24 hours before the test.

If you are breastfeeding, you may want to pump enough breast milk before the test to get through 1 to 2 days of feeding. The radioactive tracer used in this test can get into your breast milk and is not good for the baby.

How is the test done?

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.
  • You will have a tube, called an IV, going 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.
  • You will be asked to remain very still during each scan, which takes about 5 to 10 minutes. Several scans will be taken.

Stress scan using medicine

The stress scan is done in two parts. In many hospitals, you first have the resting scan. You are then given a medicine that makes your heart work harder and you have another scan. Sometimes the stress scan is done first.

  • You will have a test called an electrocardiogram (EKG or ECG), which takes about 5 to 10 minutes. You may have other EKGs during and after the stress test.
  • Medicine will be put in your IV. It will make your heart work harder. You may get a headache and feel dizzy, flushed, and nauseated from the medicine, but these symptoms usually do not last long.
  • Your heartbeat and blood pressure may be checked.
  • Your symptoms such as chest pain and shortness of breath will be checked.
  • A few minutes after you get the medicine, another small amount of radioactive tracer is injected. You may be given something to reverse the medicine used to make your heart work harder.
  • You will wait for 30 to 40 minutes and then have another resting scan.

What else should you know about the test?

  • Sometimes more pictures are taken 2 to 4 hours after the stress scan.
  • No electricity passes through your body during the test. There is no danger of getting an electrical shock.
  • Anytime you're exposed to radiation, there's a small chance of damage to cells or tissue. That's the case even with the low-level radioactive tracer used for this test. But the chance of damage is very low compared with the benefits of the test.
  • Most of the tracer will leave your body through your urine or stool within a day. So be sure to flush the toilet right after you use it, and wash your hands well with soap and water. The amount of radiation in the tracer is very small. This means it isn't a risk for people to be around you after the test.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

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.

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?

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