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What Is A Nuclear Stress Test?

A Nuclear Stress Test is done to measure your blood flow at states of rest, exertion, and medication. Through the test, your doctor can tell which areas of your heart have low blood flow. Typically, the complete test considers your heart's images when at rest and when under stress by exercise or medication. It's one of the tests that could be carried out to diagnose the likelihood of a significant Coronary Artery Diseases (narrowing of the heart arteries that can cause heart attacks).

How Do You Prepare For A Nuclear Stress Test?

You may be asked not to eat, drink, or smoke for a period of time before a nuclear stress test. You will likely also need to avoid caffeine the day before and the day of the test, as caffeine can inappropriately elevate the heart rate for the duration of the test and provide false results.



  • NO coffee, including decaffeinated or tea/herbal tea of any kind

  • NO colas or soft drinks, including those labeled caffeine-free

  • NO chocolate (candy, cakes, pies, cocoa, white chocolate, etc.)

  • NO Anacin, Excedrin, or other aspirin products containing caffeine

  • NO Persantine (Dipyridamole)

  • NO Theophylline

  • NO beta-blockers (metoprolol/Toprol, carvedilol/Coreg, atenolol, propranolol, labetalol) unless specifically told to continue these medications by your ordering provider or our staff.


  • DO NOT EAT OR DRINK 4 HOURS BEFORE YOUR TEST. (This includes gum and breath mints.)

  • DIABETIC MEDICATIONS should not be taken the morning of your test, but please bring your diabetic medicines with you.

  • If you take Lantus (insulin glargine) in the evening, take half your usual dose the evening before the test.

  • NO water pills (diuretics) until after your test.

  • Bring your medications with you in their original containers.

  • Bring a snack to eat after the stress portion of the exam.

Why Is A Nuclear Stress Test Performed?

Your doctor may opt for a Nuclear Stress Test if you experience symptoms such as shortness of breath and chest pain. Routine stress tests don’t specify the cause of these symptoms. The test can also be used to help shed light on the treatment methodology in case you’re diagnosed with a heart condition such as CAD or arrhythmia. It helps them determine how well the treatment is working and set the right treatment path. It also helps determine the amount of exercise your heart can handle comfortably.

Here are more reasons why your doctor may recommend a Nuclear Stress Test:

  • To diagnose Coronary Artery Disease (CAD): Coronary arteries are the main blood vessels tasked with supplying blood, nutrients, and oxygen to your heart. When plaque builds up in the coronary arteries, they become damaged or develop diseases. Symptoms such as shortness of breath and chest pains may indicate CAD. A Nuclear Stress Test may be necessary to determine if it really is CAD.

  • To see the size and shape of your heart: The images taken during a Nuclear Stress Test can help determine if the size and shape of your heart are normal and measure its ejection fraction (the pumping function of the heart).

Does A Nuclear Stress Test Show Blocked Arteries?

One of the main reasons why a Nuclear Stress Test may be necessary is to determine if blood is flowing freely enough through your coronary arteries. It helps identify blockages and damage in your heart blood vessels.

How Long Does A Nuclear Stress Test Take?

The Nuclear Stress Test comprises two parts: One in a resting state and another during exercise. In total, the two portions can take anywhere between two and three hours.

What Can You Expect During A Stress Test?

Before the test, a technician will insert an Intravenous Line (IV) into your hand or arm then place patches (electrodes) on your chest and arms. These patches connect to an Electrocardiogram Machine, which records your heartbeat triggers. There’s also a cuff on your arm that helps check changes in your blood pressure during the test. For the resting portion of the test, a radioactive is introduced into your bloodstream through the IV and allowed to circulate for a while. Then images of your heart are taken to show the resting blood flow.

Treadmill/Stress Portion of Nuclear Stress Test: For the stress portion, you’ll be placed on a treadmill or––if you can’t exercise adequately––given some medication through the IV. After your heart is stimulated, more radioactive is introduced into your bloodstream through the IV. And again, images of your heart muscle are taken using a machine resembling an X-Ray machine. These two images help the doctor determine the efficiency of your blood to your heart at rest and when under stress. If you’re exercising, the test will begin with a slow pace on the treadmill, which increases with speed over time. The stress test continues until your heart rate reaches a set target, but you can stop the test if you get too uncomfortable to continue.

What Is The Follow Up To A Stress Test?

When the test is complete, you may return to normal activities unless your doctor tells you otherwise. The radioactive material will naturally leave your body in your urine or stool. Make sure to drink plenty of water to help flush the medication out of your system.

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