Nuclear Stress Test
A nuclear stress test is performed to assess your blood flow at rest, during exertion, and after medication.

What Is A Nuclear Stress Test?
Nuclear Stress test allows your doctor to identify areas of your heart with reduced blood flow.
The full test typically includes imaging of your heart both at rest and under stress, either from exercise or medication.
It is one of the diagnostic tools used to evaluate the risk of Sudden Cardiac Death (SCD).
What Are the Preparation Steps for a Nuclear Stress Test?
You may be instructed to refrain from eating, drinking, or smoking for a certain period before a nuclear stress test. Additionally, you will likely need to avoid caffeine both the day before and the day of the test, as it can artificially raise your heart rate and lead to inaccurate results.
72 Hours Before
24 Hours Before Your Test
- Avoid Caffein
- No coffee, including decaffeinated varieties, or any tea/herbal tea
- No colas or soft drinks, even those labeled caffeine-free
- No chocolate (including candy, cakes, pies, cocoa, white chocolate, etc.)
- No aspirin products like Anacin or Excedrin that contain caffeine
- No Persantine (Dipyridamole)
- No Theophylline
- No beta-blockers (such as metoprolol/Toprol, carvedilol/Coreg, atenolol, propranolol, labetalol), unless your prescribing provider or our staff specifically instructs you to continue these medications.
The Day of Your Test
- Do not eat or drank for 4 hours prior to your test. (This includes gum and breath mints.)
- Diabetic Medications
- Do not take water pills (diuretics) until after the test.
- Bring your medications in their original containers.
- Bring a high-fat snack to eat after the stress portion of the test.
- Remember to bring your insurance cards with you.
What Is the Purpose of a Nuclear Stress Test?
Your doctor may recommend a Nuclear Stress Test if you experience symptoms like chest pain and shortness of breath, as routine stress tests don’t always identify the underlying cause of these issues.
The test can also assist in guiding treatment if you’re diagnosed with heart conditions such as Coronary Artery Disease (CAD) or arrhythmia. It helps assess how effective your current treatment is and allows your doctor to adjust your care plan accordingly. Additionally, it provides insight into how much exercise your heart can handle safely.
- To diagnose Coronary Artery Disease (CAD): CAD occurs when plaque builds up in the coronary arteries, which supply oxygen-rich blood to the heart. This can lead to damage or disease in the arteries. Symptoms like chest pain and shortness of breath may point to CAD, and a Nuclear Stress Test can confirm if this is the case.
- To evaluate the size and shape of your heart: The images captured during a Nuclear Stress Test can reveal if your heart's size and shape are normal, and measure its ejection fraction (the heart's pumping efficiency).
Does a Nuclear Stress Test Identify Blocked Arteries?
What is the Duration of a Nuclear Stress Test?
- Renal MRI or CT Scan: These imaging tests offer more detailed views of the renal arteries and can help identify other abnormalities, such as tumors or cysts.
- Renal Nuclear Medicine Scan: This test uses a small amount of radioactive material to assess kidney function and blood flow.
- Renal Angiogram: This procedure involves injecting contrast dye into the renal arteries and using X-ray imaging to evaluate blood flow and detect blockages or narrowing. It is more invasive than a renal artery ultrasound and carries a higher risk of complications.
What Happens During a Stress Test?
When you arrive, your doctor will ask about your medical history and your physical activity habits.
Before the test begins, a technician will insert an intravenous (IV) line into your hand or arm and attach electrodes (patches) to your chest, arms, and legs. These electrodes connect to an electrocardiogram (ECG) machine that monitors your heartbeat. A cuff will also be placed around your arm to measure changes in your blood pressure during the test.
During the resting portion of the test, a radioactive dye will be injected into your bloodstream via the IV, and images of your heart will be taken to assess blood flow while at rest.
For the stress portion of the test, you will either walk on a treadmill or ride a stationary bike. If you cannot exercise adequately, medication will be given through the IV to stimulate your heart. Afterward, more radioactive dye will be injected into your bloodstream, and additional images of your heart will be captured using equipment similar to an X-ray machine.
The two sets of images help the doctor evaluate how well blood flows to your heart both at rest and under stress.
Depending on the medication used, side effects may include shortness of breath or flushing, similar to the effects of exercise.
If you’re exercising, the treadmill will start at a slow pace and gradually increase in speed. The doctor will ask you not to grip the railing tightly, as it may affect the results. If you’re using a stationary bike, the resistance will increase as the test progresses.
The test continues until your heart reaches a target heart rate, but you can ask your doctor to stop the test if you feel uncomfortable.
What Is the Follow-Up Process After a Stress Test?
What Are the Possible Risks of a Nuclear Stress Test?
Although the test involves some exposure to radiation, a Nuclear Stress Test is generally considered safe. Complications are rare but may include:
- Allergic reactions to the radioactive dye
- Arrhythmias triggered by exercise or medication, which typically resolve once the exercise ends or the medication wears off
- Heart attack, though this is extremely rare
- Chest pain or flushing, which are usually brief but should be reported to your doctor immediately if they occur
Are There Other Treatments Related to This?
An alternative to a nuclear stress test is an exercise stress test, where the patient runs on a treadmill while EKG electrodes are attached to monitor and assess cardiac activity.