What is a stress nuclear test?
A cardiac (heart) nuclear study is a test that uses a small dose of radioactive solution to track blood flow to the heart muscle, and to evaluate heart function.
A treadmill stress test evaluates your heart’s response to physical activity through the monitoring of your heart rate, blood pressure, and electrocardiograms while you exercise on a treadmill.
When the two tests are combined, an assessment can be made of the status of the blood supply to your heart at rest, as well as during stress. This can provide your doctor with information regarding whether or not you have significant blockages in your heart arteries. The test also includes an assessment of the pumping function of your heart.
Common reasons to have this test:
To determine if coronary artery disease is present and if further studies and/or treatment are required.
To evaluate progress following a major cardiac event (heart attack, heart surgery).
To evaluate whether a blockage found during an angiogram requires angioplasty.
To follow the progress of documented coronary artery disease.
Preparing for the test:
DO NOT consume any caffeinated beverages (coffee, tea, pop/soda), chocolate, or product containing caffeine for 24 hours before the test.
DO NOT eat, drink or smoke for 3 hours before the test. Small amounts of water are allowed.
DO NOT use body oils or body lotions the day of the test.
Do take your usual medications with water, unless instructed otherwise by your doctor or nurse.
Diabetics who use insulin or glucose lowering agents may need to adjust their dosage. Please check with your physician if you are not sure.
Wear loose fitting clothing that allows easy access to the chest, and comfortable walking shoes.
The entire test will take approximately 2 hours, although you will be walking on the treadmill for approximately 10 minutes of that time.
An IV will be started in your arm and a small dose of radioactive solution will be injected. After this injection, you will be asked to wait approximately 45 minutes to allow this material to be taken up by your heart cells.
After the 45 minute wait time, you will be asked to disrobe from the waist up and will be provided with a gown to wear. Next you will lie on a scanning table and a special camera (gamma camera) will be positioned close to your chest, and you will be asked to lie still. The gamma camera takes pictures of your heart. This part of the test takes approximately 20 minutes.
After the image session, a specially trained nurse will place electrodes on your chest and wires will be attached to the electrodes so that the electrocardiogram (ECG) can be monitored continuously during the test. In men, limited shaving of the chest may be required to assure good contact between the skin and the electrodes. A blood pressure cuff will be placed on your arm so that your blood pressure can be measured before, during, and after exercise.
You will then walk on a treadmill machine, which is an electrical walkway that can be raised. The speed and incline will increase gradually, such that you will be walking uphill. Your blood pressure will be checked intermittently and from time to time you will be asked if you are experiencing any symptoms. You will be encouraged to exercise for as long as you can. If you notice chest pain, dizziness, weakness, lightheadedness, or leg fatigue, inform the nurse. Near the end of the stress test, you will receive another injection of a radioactive solution so that blood flow to your heart during stress can be assessed. After stopping exercise, you will continue to be monitored until your heart rate and blood pressure return to pre-exercise levels.
Finally, you will lie back down on the scanning table to be imaged by the gamma camera for another 20 minutes.
Is it safe?
Stress testing is very safe. The likelihood of a serious complication (such as a heart attack or death) is less than 1 in 10,000. It is important to keep in mind that you will be continuously and extensively monitored throughout the test by experienced personnel and that the test will be stopped if there is any indication that continuing exercise would be unsafe in any way.
There are no reports of allergic reactions or side effects related to injection of the radioactive solutions. The radiation exposure from the test is very small (equivalent to that of several chest x-rays) and not associated with any significant health risk.
When will I receive my test results?
Your test will be reviewed and interpreted by a cardiologist and a report will be provided to your physician who will contact you.