- 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.
- The appointment will take about 1 to 2 hours. The actual exercise part of the test lasts about 7-12 minutes.
- Please wear comfortable clothes and shoes suitable for walking during the test.
- Do not eat or drink anything for 4 to 6 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, colas, and chocolate products.
- Also avoid decaffeinated or caffeine-free products for 24 hours before the test, as these products contain trace amounts of caffeine.
- If you have diabetes, you will be given specific instructions.
- 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 medications without first talking with your physician.
HOW THE TEST IS PERFORMED
- 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 15-20 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 (electrocardiogram).
- 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.
- The cardiologist will review your test and provide you with the results. Your referring physician will also obtain a copy of these results.
- There may be possible risks. When you meet with your doctor, please ask questions to make sure you understand why the procedure is recommended and what the potential risks are.