Cardiac perfusion scan

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. Medicine or exercise can be used to increase the amount of blood that your heart needs.

During the scan, a camera takes pictures of your heart after a radioactive tracer is put 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 the 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).

A cardiac perfusion scan is done to:

• Find the cause of unexplained chest pain or pressure.
• Find the cause of chest pain or pressure brought on by exercise.
• Check for the location and amount of damage caused by a heart attack.
• Identify coronary artery disease (CAD).
• Help make treatment decisions for a person with CAD.
• Check to see that the heart is getting enough blood after heart surgery or angioplasty.
• Identify a congenital heart defect and determine how serious it is. These scans may also be done following surgery to correct a congenital heart defect.

A cardiac perfusion test can be done while you're resting, after you exercise, or after you take medicine. Or you could have the test after taking medicine and exercising.

Before the scans, electrodes will be attached to your chest to help record your heartbeats. You will have a tube, called an I.V., put into your arm. Radioactive tracer will be put in the I.V.

• For the resting scan, you will lie on a table. A camera above your chest records the tracer that has moved from your blood into your heart muscle. Several scans will be taken. They take 10 to 30 minutes each.
• For an exercise scan, you will walk on a treadmill or pedal a stationary bike. Then you have the scan.
• For a medicine scan, you are given a medicine in your IV that increases the amount of blood that your heart needs. Then you have the scan.

Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies 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 a medicine that prevents blood clots, your doctor may tell you to stop taking it before your test. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.

You may be told not to eat or drink for several hours before the scan. You may be told to avoid alcohol, tobacco, and drinks that have caffeine for at least 24 hours before the test.

Wear comfortable shoes, such as running shoes, and loose shorts or pants. Don't wear jewelry to 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.

Test results are usually available within 1 to 3 days.

Results are:

• Normal if radioactive tracer is evenly distributed throughout your heart muscle.
• Abnormal if areas of abnormal tracer absorption are present. This means some areas of heart muscle are not getting enough blood (ischemia). This may mean that the heart has been damaged or that coronary artery disease is present.