What is a nuclear exercise stress test?
A nuclear exercise stress test is a diagnostic test used to evaluate blood flow to the heart. During the test, a small amount of radioactive tracer is injected into a vein. A special camera, called a gamma camera, detects the radiation released by the tracer to produce computer images of the heart.
Combined with exercise, the test can help determine if there is adequate blood flow to the heart during activity versus at rest.
Can I eat or drink on the day of the test?
Yes. However, DO NOT eat or drink anything for 4 hours before the test. If you must take medications, drink only small sips of water to help you swallow your pills.
Avoid all products containing caffeine for 24 hours before the test. In general, caffeine is found in coffee, tea, soft drinks and chocolate products.
Also avoid decaffeinated or caffeine-free products for 24 hours before the test, as these products contain trace amounts of caffeine.
Should I take my medications the day of the test?
Please bring a copy of all of your medications, including over-the-counter medications and supplements that you routinely take, to the test appointment.
Please follow these guidelines about taking your medications the day of the test.
- Medications with caffeine: DO NOT take any over-the-counter medication that contains caffeine (such as Excedrin®, Anacin®, diet pills and No Doz®) for 24 hours before the test. Ask your physician, pharmacist or nurse if you have questions about other medications that may contain caffeine.
- If you have asthma: Your physician will tell you NOT to take theophylline (Theo-Dur®) for 48 hours before the test. Please plan to bring your asthma inhaler mediation to the test.
- If you have diabetes: If you take insulin to control your blood sugar, ask your physician how much insulin you should take the day of the test. Your physician may tell you to take only half of your usual morning dose and to eat a light meal 4 hours before the test. If you take pills to control your blood sugar, do not take your medication until after the test is complete. Bring your diabetes medications with you so you can take it when the test is complete. Do not take your diabetes medication and skip a meal before the test. If you own a glucose monitor, bring it with you to check your blood sugar levels before and after your test. If you think your blood sugar is low, tell the lab personnel immediately. Plan to eat and take your blood sugar medication following your test.
If you take heart medications: DO NOT take the following heart medications on the day of the test unless your physician tells you otherwise, or unless it is needed to treat chest discomfort the day of the test:
- Isosorbide dinitrate (for example: Dilatrate®, Isordil®)
- Isosorbide mononitrate (for example: Imdur®, ISMO®, Monoket®)
- Nitroglycerin (for example: Minitran®, Nitropatches®, Nitrostat®)
- Dipyridamole (Persantine®): Stop taking 48 hours before the test
Your physician may also ask you to stop taking other heart medications on the day of your test. If you have any questions about your medications, ask your physician. Do not discontinue any medication without first talking with your physician.
What should I wear for the test?
Please wear comfortable clothes and shoes suitable for walking during the test.
What to expect during the test
- The testing area is supervised by a physician.
- A nuclear medicine technologist will place an IV into a vein in your arm or hand and inject a small amount of radioactive tracer. The tracer is not a dye or contrast. After the tracer is injected, you will wait about 20 minutes before the first set of “resting” images are taken.
- Then you will be asked to lie very still under the gamma camera with both arms above your head for about 15 to 20 minutes. The camera will record images that show blood flow through your heart at rest.
- Next, a technician will place electrodes on your chest to monitor your EKG.
- You will start walking on a treadmill. At regular intervals, the difficulty of the exercise will increase until you achieve the target heart rate. Then, a second dose of radioactive tracer will be injected into the IV. Your heart rate, EKG and blood pressure will be monitored throughout the test. If you are unable to achieve your target heart rate, a medication may be given to simulate exercise.
- About 30 minutes after exercising, you will be asked to again lie very still under the camera with both arms over your head for about 15-20 minutes. The camera will record images that show blood flow through your heart during exercise. These images will be compared to the first set.
How long will the test last?
The appointment will take about 2 - 3 hours. The actual exercise part of the test lasts about 7 - 12 minutes.
How do I get the results of my test?
After the cardiologist reviews your test, the results will go into your electronic medical record. Your referring physician will have access to the results and will contact you to discuss them.