Nuclear Cardiac Stress Test What is and How Does it Work
The nuclear cardiac stress test uses a small amount of radioactive substance (tracer or radiopharmaceutical) and an imaging device to display how blood flows to the heart. The test measures blood flow while resting and during activity and shows areas of poor blood flow or damage to the heart.
Your health care provider injects a small amount of the tracer into the bloodstream. The blood vessels and heart muscles absorb the tracer, making them more visible in the images. The provider then uses a special camera to take pictures of the blood flow in and around the heart.
A nuclear cardiac stress test is only one of the various existing stress tests. To your knowledge, a radiolabel used during a nuclear cardiac stress test serves to help your physician assess the risk of a heart attack or any cardiac episode in case you have coronary artery disease.
Patients may undergo a nuclear cardiac stress test after a regular exercise stress test to learn more about their heart, or it may be the first stress test used.
Doctors have their patients do this test with a positron emission technology (PET) scanner or a single-photon emission computed tomography (SPECT) scanner. Medical staff may also call the nuclear cardiac stress test, myocardial perfusion imaging (MPI) study, cardiac PET study, or cardiac SPECT study.
Another way a nuclear cardiac stress test can be classified is whether it involves physical activity or medication to stress the heart:
- Exercise stress test:
You run on a treadmill or use a stationary bike to maximize blood flow to the heart and meet a target heart rate.
- Pharmacologic stress test:
If you cannot exercise, you receive medication to increase blood flow and stress the heart.
Why Perform A Nuclear Cardiac Stress Test
You probably require a nuclear cardiac stress test if you have symptoms or signs of heart disease, such as chest ache or shortness of breath. Doctors also use a nuclear cardiac stress test to guide treatment if they have diagnosed you with heart disease.
Your health provider may suggest a nuclear cardiac stress test for the following:
- Diagnosing a coronary artery disease:
The primary blood vessels that supply blood, oxygen, and nutrients to the heart are the coronary arteries. Coronary artery disease happens when these arteries become damaged or diseased, usually due to a buildup of deposits containing cholesterol and other substances, like plaques.
If you are experiencing shortness of breath or chest ache, a nuclear cardiac stress test may help identify if you have coronary artery disease and if the condition is severe.
- Determine a treatment plan for your condition:
For example, when you have coronary artery disease, a stress test can tell your physician if the treatment is functioning as it should be. The test also helps your physician develop the proper treatment for you by determining how much exercise your heart can handle.
What Does A Nuclear Cardiac Stress Test Show
Cardiologists usually use the Nuclear Cardiac stress Test to diagnose and monitor coronary artery disease (CAD) by showing blood flow to the heart. CAD happens when blood vessels are clogged or blocked.
This test can also:
- Determine if your heart muscle is pumping well.
- Identify poor blood flow.
- Locate blocked arteries.
- Show if your heart has been damaged, for example, by a heart attack.
People with the following issues may also use this test:
- Severe coronary syndrome.
- Bundle branch block.
- Congestive heart failure.
- Other suspected or confirmed heart problems.
- Shortness of breath.
Cardiologists often order this test. They may perform the test themselves, or a radiology technologist may perform the test.
Nuclear Cardiac Stress Test Risks
A nuclear cardiac stress test is usually safe. Complications are rare. Like any medical procedure, it can bring difficulties, which may include the following:
- Arrhythmias (abnormal heart rhythms):
Arrhythmias that occur on a stress test usually go away quickly when you stop exercising, or the effect of the medication wears off. Life-threatening arrhythmias are rare.
- Heart attack:
Although extremely rare, a nuclear cardiac stress test causes a heart attack.
- Low blood pressure:
Your blood pressure may drop during exercise or immediately afterward; you may feel dizzy or faint. However, this problem should disappear after you stop exercising.
- Dizziness or chest ache:
These symptoms may appear while you are performing a this stress test. Some individuals also have shortness of breath, nausea, headache, shakiness, flushing, and anxiety when doing the stress test. These symptoms and signs are generally mild and brief, but report them to your physician if they happen.
This test involves a small dose of radiation exposure. Radiation exposure can cause cancer, yet scientists believe it requires large or frequent quantities.
You should not have a nuclear cardiac stress test if you have certain conditions that are serious or uncontrolled, such as:
- Arrhythmia
- Aortic stenosis, which is a narrowed aorta.
- Angina pectoris.
- Aortic dissection.
- Infection of the heart.
- Congestive heart failure.
- Pulmonary hypertension.
- Pulmonary embolism.
A Stress Test Versus A Nuclear Cardiac Stress Test
A standard exercise stress test and a nuclear cardiac stress test are similar. Both evaluate your heart’s electrical activity using an electrocardiogram (EKG). Both consider how your heart works under stress. But a cardiac test is a more advanced method that provides more specific data.
An exercise stress test utilizes only an EKG to monitor your heart while you rest and then exercise. Instead, a nuclear stress test includes images of your heart before and after exercising from the particular camera.
How To Get Ready For A Nuclear Cardiac Stress Test
Your physician will provide you with detailed directions on how to prepare for this stress test, and these may include:
- Avoid beverages, food, and medications containing caffeine for twenty-four hours before the test. Some examples include soft drinks, coffee, tea, and chocolate.
- Carry anything that helps you breathe, such as your inhaler.
- Do not smoke before the test.
- Inform your physician about any medications you take, including prescription drugs, illegal drugs, over-the-counter medications, and supplements.
- Do fasting, so do not eat or drink anything but water for a few hours beforehand.
- Wear tennis shoes and comfortable clothing.
Your physician may ask you to skip certain medicines before the test or change your dose. Either way, it would be best if you did not change the way you take prescribed medications without talking to your doctor, who gave them to you first.
What To Expect During A Nuclear Cardiac Stress Test
A specialized technician, a radiology technologist, a cardiologist, or a physician can perform this test in a hospital or clinic.
Members of the medical staff will:
- Insert an IV into your arm to inject the tracer into your bloodstream, which may initially feel cold.
- Wait a few minutes for the tracer to circulate and reach the heart.
- Place patches (electrodes) on your skin, usually on your chest, arms and legs. You may shave your hair a little to make the patches stick.
- Connect the patches to an electrocardiograph to measure the electrical activity of your heart.
- Put a cuff on your arm to monitor your blood pressure.
- Ask you to lie on a table and lie still so they can take pictures with a special camera.
- Instruct you to exercise on a treadmill or stationary bike, starting slowly and increasing the intensity.
- Ask you to keep exercising until you reach a target heart rate or experience bothersome symptoms. You may stop this test at any moment if you do not feel comfortable continuing.
- Inject more tracer substances into your bloodstream.
- Ask you to lie back down on a stretcher to take the second set of images after exercise.
A health care provider may inject medicine into your arm if you have a medical condition that does not allow you to exercise. The medication stimulates the heart and enhances blood flow to imitate exercise conditions.
A stress test generally lasts about three to four hours.
What To Avoid After A Nuclear Cardiac Stress Test
Your physician will give you directions to follow after having the test. Typically, people may return to their normal activities right away. However, you may want to drink plenty of fluids to help flush the tracer substance out of your body.
After the test, you may have a headache, fatigue, or somewhat drowsy. These symptoms should vanish with time and rest.
Results From The Nuclear Cardiac Stress Test And Follow-up
You will have nuclear cardiac stress test results after a few days. A cardiologist, a specialized technician, or a radiologist should review the images and interpret the results.
This will help to diagnose and monitor heart problems such as CAD, among others.
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