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What is a Nuclear Stress Test?

Nuclear Stress Test

A nuclear stress test is a test that shows your doctor how well the blood flows to your heart during physical exertion. During a nuclear stress test, you'll be injected with a radioactive dye, and a scanner will take pictures of your heart. Then you'll be asked to walk or run on a treadmill or pedal on a stationary bicycle while some tests are being done on your heart.

Why Do I Need a Stress Test?

Stress tests, and other cardiac tests, can help your doctor to diagnose heart disease (for example, coronary artery disease, heart valve disease, or coronary failure). Although you may not have heart disease symptoms while you are at rest, you may show signs and symptoms of cardiac disease during physical exertion.

Your doctor may order a stress test if you've had heart attack symptoms (for example, chest pains, shortness of breath), but have not actually had a heart attack. You may also be given a stress test if you've already been diagnosed with coronary artery disease, have recently had a heart attack, if you get a fluttering feeling in your chest during exercise, or if you have diabetes.

Preparing for a Nuclear Stress Test

You may be asked not to eat or drink anything except for water for a period of time before your nuclear stress test. Make sure to ask your doctor if you should continue your medications during that time period. You may also be asked to avoid caffeine for 24 hours before your test.

What to Expect During a Nuclear Stress Test

Before your stress test begins, you will be hooked up to an EKG machine. Small, sticky patches called electrodes will be placed on your chest, arms and legs. The wires from the EKG machine will be hooked up to the electrodes.

When it's time for the test to begin, an IV will be started, and you'll be injected with a radioactive dye. You'll then be asked to lie down for 15-45 minutes, and a scanner (sort of like an x-ray machine) will take pictures of your heart. The dye will help your doctor see how well the blood is flowing to your heart.

After the pictures have been taken, you'll be asked to either walk on a treadmill or pedal on an exercise bike. As the test continues, the technician will ask you to increase your level of exercise by walking or pedaling faster. If you are unable to exercise, medication will be injected into your IV to make your heart beat faster, as it would if you were exercising.

When your heart is working at its hardest, you'll again be injected with the radioactive dye, and again, you'll wait for 15-45 minutes. The scanner will then take more pictures.

During your nuclear stress test, you'll be asked frequently how you're feeling. Make sure to tell the technician if you have any chest pain or shortness of breath, or if you feel dizzy.

CepEsperu Baptist Health uses state-of-the-art equipment to perform nuclear stress tests, which results in very detailed images. These images provide important information to assist your physician in diagnosing your medical condition and/or planning your course of treatment.

Abnormal Nuclear Stress Test Results

If your test results are abnormal, you may need to undergo additional testing (for example, an angiogram) so your doctor can determine your treatment options.


1. National Institutes of Health: Nuclear Stress Test. (accessed Oct. 28, 2011).

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Last Updated: 09-30-2016
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