Key Points about a Nuclear Cardiac Stress Test
- There are two types of nuclear cardiac stress tests – with exercise and non-exercise.
- A nuclear cardiac stress test determines blood flow to the heart during rest and stress.
- This test involves having your heart rate and blood flow monitored while exercising on a treadmill at escalating or increasing intensities or through a medication that mimics the stress induced by exercise. This allows the doctor to assess how well the heart compensates with increased blood flow.
A nuclear cardiac stress test is a diagnostic test that creates images to help a doctor measure blood flow to the heart. There are two types of nuclear cardiac stress tests – with exercise and non-exercise. While both assess your blood flow to the heart at peak stress and at rest, a stress test with exercise uses a treadmill workout to initiate cardiac stress while non-exercise uses a medication.
For this assessment, your doctor will inject a radioactive tracer into a vein in your arm or hand through an IV line. This tracer allows the doctor to take images of blood flow in the body. This material will not affect you in any way.
After injection, you will wait 60 minutes to allow the tracer to circulate to your heart. Nuclear technologists will use a Nuclear SPECT (single-photon emission computerized tomography) camera to take images of your heart at rest. Whether you are doing an exercise or non-exercise test, your second set of images will be taken between 45 minutes and three hours following exercise or medication injection.
A cardiologist will compare images obtained during rest and stress to determine blood flow.
Nuclear cardiac stress test with exercise
A nuclear cardiac stress test measures blood flow to the heart at escalating levels of exercise and heart rate to ensure that adequate blood is being pumped to the heart.
After you receive the radioactive tracer and the first set of images are taken of your heart, you will move to a stress room where electrodes will be put on your chest to monitor your blood pressure, heart rate and EKG during the exercise. You will perform a graded exercise test on a treadmill that begins at a slow speed and slight incline, both of which will be increased every three minutes.
About 90 seconds before your exercise ends, a second dose of radioactive tracer is injected through your IV line and is allowed to circulate during the last minute of the workout. A nurse will monitor your heart rate, blood pressure and EKG throughout the stress portion of the test. The second set of images will be taken between 45 minutes and three hours after your exercise ends.
Nuclear cardiac stress test without exercise
You may be unable to complete a nuclear cardiac stress test with exercise. In the event that you perform a cardiac stress test without exercise, a medication called Lexiscan is administered in place of a physical workout.
The first portion of the test is the same: you will be injected with a radioactive tracer through an IV line and wait 60 minutes for it to circulate to your heart before taking the first set of images using the Nuclear SPECT camera.
Once you move to the stress room and electrodes are placed on your chest to monitor your blood pressure, heart rate and EKG, the Lexiscan will be administered over about 30 seconds. Immediately following the Lexiscan, you’ll receive a second dose of radioactive tracer and the burse will continue to monitor your vital signs.
Your second set of nuclear images will be taken one to three hours after your second injection of tracer.
Candidates for a nuclear cardiac stress test
You may be a candidate for a nuclear cardiac stress test if you:
- Have coronary artery disease
- Are experiencing cardiac symptoms such as shortness of breath or chest pain
Expectations for a nuclear cardiac stress test
With a stress test, you need to:
- Avoid eating or drinking after midnight before your test
- Abstain from foods, beverages and medications containing caffeine for 24 hours before your test – this includes decaffeinated soft drinks, decaf tea and coffee, green tea, and chocolate
- Perform seven to 12 minutes of exercise or receive a medication that mimics stress from exercise
- Have a radioactive tracer administered through an IV
- Have an EKG attached to your chest
- Have images taken of your heart as you recline on a table before and after exercise
- Wear loose, comfortable clothing and comfortable walking shoes
The entire testing experience will take three to five hours. You should continue to take all medications up to midnight before your test unless directed otherwise by your cardiologist.
Benefits of a nuclear cardiac stress test
Doctors may use a nuclear cardiac stress test to:
- Identify coronary artery disease
- Gather information about to how to treat a specific heart condition
- Highlight your potential risk of experiencing a heart attack
Risks of a nuclear cardiac stress test
There are no serious risks accompanying a nuclear stress test. Possible but rare symptoms and risks may include:
- Heart attack
- Chest pain
- Low blood pressure
- High blood pressure
Recovery from a nuclear cardiac stress test
Following a nuclear stress test, you can return to activities as normal. You will be advised to drink lots of water to flush the radioactive dye out of your body naturally.
However, if you will be traveling by airplane or out of the country by car or cruise ship within one week of your nuclear study, please notify the staff so you may receive the appropriate documentation of your recent nuclear study.