A nuclear cardiac stress test helps diagnose and monitor heart problems such as coronary artery disease. A provider injects a small amount of radioactive substance into your bloodstream. Then a special camera takes pictures of blood flow in and around the heart. The test has two phases: once when you’re resting and once after you exercise.
This test helps diagnose heart disease. A healthcare provider injects a small amount of a radioactive substance (called a tracer or radiopharmaceutical) into the bloodstream. Your blood vessels and heart muscle absorb the tracer, making them more visible in images. Then the provider uses a special camera to take pictures of blood flow in and around the heart.
The test may also be called:
A healthcare provider can use two different imaging technologies for a nuclear cardiac stress test: PET or SPECT.
Another way a nuclear stress test can be classified is whether it involves physical activity or medication to stress the heart:
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Cardiac stress testing is commonly used to diagnose and monitor coronary artery disease (CAD) by showing blood flow to your heart. CAD occurs when blood vessels are clogged or blocked.
The test can also:
It also may be used in people with:
Cardiologists (heart doctors) often order this test. They may conduct the test themselves, or a radiology technologist can perform the test.
A regular exercise stress test and a nuclear stress test are similar. Both assess your heart’s electrical activity using an electrocardiogram (EKG). Both evaluate how your heart performs under stress. But a nuclear stress test is a more advanced method that provides more detailed information.
An exercise stress test uses only an EKG to monitor your heart while you’re resting and then exercising. But a nuclear stress test includes images of your heart. A tracer is injected into your veins, and a special camera takes pictures of your heart before and after exercise.
Your healthcare provider will give you specific instructions to help you prepare for the test. The instructions may include:
Your healthcare provider may ask you to skip certain medications before the test or change the dose. But don’t change the way you take prescription medications without talking to your doctor first.
The test is usually performed in a hospital or clinic by a specialized technician or doctor.
A healthcare provider will:
If you have a medical condition that prevents you from exercising, a healthcare provider can inject a medication into your arm. The medication stimulates the heart and increases blood flow to mimic exercise conditions.
A nuclear stress test usually takes about three or four hours.
Your healthcare provider will give you instructions to follow after the test. People usually can go back to normal activities immediately. You may want to drink plenty of fluids to help flush the tracer out of your body.
After the test, you may feel tired or dizzy or have a headache. Those symptoms should go away with time and rest.
Nuclear stress tests are generally safe. But the procedure can cause a problem in about 1 in 5,000 people, such as:
The procedure involves a small amount of radiation exposure. Radiation exposure can cause cancer, but scientists believe that requires large or frequent doses.
You should not have a nuclear stress test if you have certain conditions that are severe or not controlled, such as:
Results of a nuclear stress test may take a few days. A healthcare provider such as a cardiologist or radiologist must review the images and interpret the results.
A note from Cleveland Clinic
A nuclear cardiac stress test helps diagnose and monitor heart problems such as coronary artery disease. A healthcare provider connects you to an EKG machine, injects a tracer into your bloodstream and takes images of blood flow to your heart before and after exercise. If you need a stress test, tell your doctor about any medications you take, and ask how you should prepare.
Last reviewed by a Cleveland Clinic medical professional on 05/31/2022.
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