A scanner.
A cardiac nuclear scan is a test that measures blood flow to the heart when a person is resting and when he or she is exercising. The test looks for problems such as:

  • Not enough blood reaching a portion of the heart.

  • The heart muscle not working normally.

You may need this test if:

  • You have heart disease.

  • You have had abnormal lab results.

  • You have had heart surgery or a balloon procedure to open up blocked arteries (angioplasty).

  • You have chest pain.

  • You have shortness of breath.

In this test, a radioactive dye (tracer) is injected into your bloodstream. After the tracer has traveled to your heart, an imaging device is used to measure how much of the tracer is absorbed by or distributed to various areas of your heart. This procedure is usually done at a hospital and takes 2–4 hours.

Tell a health care provider about:

  • Any allergies you have.

  • All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.

  • Any problems you or family members have had with anesthetic medicines.

  • Any blood disorders you have.

  • Any surgeries you have had.

  • Any medical conditions you have.

  • Whether you are pregnant or may be pregnant.

What are the risks?

Generally, this is a safe procedure. However, problems may occur, including:

  • Serious chest pain and heart attack. This is only a risk if the stress portion of the test is done.

  • Rapid heartbeat.

  • Sensation of warmth in your chest. This usually passes quickly.

  • Allergic reaction to the tracer.

What happens before the procedure?

  • Ask your health care provider about changing or stopping your regular medicines. This is especially important if you are taking diabetes medicines or blood thinners.

  • Follow instructions from your health care provider about eating or drinking restrictions.

  • Remove your jewelry on the day of the procedure.

What happens during the procedure?

  • An IV will be inserted into one of your veins.

  • Your health care provider will inject a small amount of radioactive tracer through the IV.

  • You will wait for 20–40 minutes while the tracer travels through your bloodstream.

  • Your heart activity will be monitored with an electrocardiogram (ECG).

  • You will lie down on an exam table.

  • Images of your heart will be taken for about 15–20 minutes.

  • You may also have a stress test. For this test, one of the following may be done:

    • You will exercise on a treadmill or stationary bike. While you exercise, your heart’s activity will be monitored with an ECG, and your blood pressure will be checked.

    • You will be given medicines that will increase blood flow to parts of your heart. This is done if you are unable to exercise.

  • When blood flow to your heart has peaked, a tracer will again be injected through the IV.

  • After 20–40 minutes, you will get back on the exam table and have more images taken of your heart.

  • Depending on the type of tracer used, scans may need to be repeated 3–4 hours later.

  • Your IV line will be removed when the procedure is over.

The procedure may vary among health care providers and hospitals.

What happens after the procedure?

  • Unless your health care provider tells you otherwise, you may return to your normal schedule, including diet, activities, and medicines.

  • Unless your health care provider tells you otherwise, you may increase your fluid intake. This will help to flush the contrast dye from your body. Drink enough fluid to keep your urine pale yellow.

  • Ask your health care provider, or the department that is doing the test:

    • When will my results be ready?

    • How will I get my results?

Summary

  • A cardiac nuclear scan measures the blood flow to the heart when a person is resting and when he or she is exercising.

  • Tell your health care provider if you are pregnant.

  • Before the procedure, ask your health care provider about changing or stopping your regular medicines. This is especially important if you are taking diabetes medicines or blood thinners.

  • After the procedure, unless your health care provider tells you otherwise, increase your fluid intake. This will help flush the contrast dye from your body.

  • After the procedure, unless your health care provider tells you otherwise, you may return to your normal schedule, including diet, activities, and medicines.

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.