What is a pharmacological nuclear stress test?
A pharmacological nuclear 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 a medication, the test can help determine if there is adequate blood flow to the heart during activity versus at rest. The medication does not increase your heart rate. The medication dilates blood vessels leading into the heart, increasing blood flow, therefore simulating exercise for patients unable to exercise on a treadmill.
Can I eat or drink on the day of the test?
The short answer is no. However, you may drink small sips of water to help you swallow your medications. Avoid all products that contain caffeine for 24 hours before the test. In general, caffeine is found in coffee, tea, colas and other soft drinks, most chocolate products, as well as strawberries (these contain a small amount of caffeine), as caffeine will interfere with the results of the test. Also avoid decaffeinated or caffeine-free products for 24 hours before the test, as these products contain trace amounts of caffeine.
DO NOT SMOKE ON THE DAY OF THE TEST, as nicotine will interfere with the results of your test.
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 NoDoz®) 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 medication 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 doctor may tell you to take only half of your usual morning dose and to eat a light meal four 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: Your instruction sheet from our office will advise you if there are any medications you should not take.
What to expect during the test
Your test will take place in Nuclear Medicine located at JB-3 (in the basement of the Miller Family Pavilion). 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 30 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. Before the medication is infused into the IV, the technician will discuss the possible side effects so you will know what to expect.
You will lie on the exam table for the duration of the test. Your heart rate, EKG and blood pressure will be monitored throughout the test. After waiting about 30 minutes, 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 cardiac stress/activity. These images will be compared to the first set.
How long will the test last?
The appointment will take about three-four hours. The first part of the appointment will take about 90 minutes. The second part of the appointment will take about two-three hours. If you weigh over 300 pounds, your test may be scheduled as a two-day test.