Nuclear Cardiac Imaging
A cardiac nuclear imaging stress test is a diagnostic procedure that uses radioactive tracer to detect how well the blood and oxygen in your arteries is flowing to your heart muscle during rest and at stress (when your heart is working harder).
Your provider may order this test to find out:
- How well a treatment (medicines, angioplasty, or heart surgery) is working.
- If you are at high risk for heart disease or complications.
- If you are planning to start an exercise program or have surgery.
- The cause of new chest pain or worsening angina.
- What you can expect after you have had a heart attack.
The results of a nuclear stress test can help:
- Determine how well your heart is pumping.
- Determine the proper treatment for coronary heart disease.
- Diagnose coronary artery disease.
- See whether your heart is too large.
How to Prepare for the Test
- Fasting (no eating) is required for 4 hours before the procedure. You may drink sips of water.
- Avoid taking anything with caffeine for 24 hours before the test, including: coffee or tea (even decaffeinated), chocolate, sodas, energy drinks, medications, or herbal supplements that may contain caffeine.
- Theophylline medications should be stopped 48 hours prior to the test.
- If you are diabetic, please consult your physician for special instruction on when to take your diabetes medications.
- Do not apply any creams, lotions, or powder to your chest area on the day of your test.
- The procedure will be explained to you and you will have the opportunity to ask any questions that you might have about the procedure.
- You will be asked to sign a consent form that gives your permission to perform the test. Read the form carefully and ask questions if something is not clear.
- If you are pregnant or suspect that you may be pregnant, you must notify the staff.
- Notify the staff of all medications (prescription and over‐the‐counter) and herbal supplements that you are taking.
- Notify the staff if you have a pacemaker, defibrillator, or any other implanted devices.
- Please wear comfortable clothing as well as a pair of comfortable walking shoes or sneakers. Avoid wearing pull-on/slip-on shoes.
- Based upon your medical condition, your physician may request other specific preparation.
What to Expect on the Day of Your (3 part) Test
- After you are checked-in and registered at the front desk, you will be brought back to have an intravenous (IV) line started.
- A radioactive tracer, thallium or sestamibi, will be injected through the IV line.
- You will wait up to 45 minutes to allow the tracer to be absorbed in your heart muscle prior to being scanned with a special camera to acquire images of your heart at rest. Typically, this may take at least 15 to 20 minutes. This is the first part of the test.
- Next, you will be taken into the stress lab to proceed with the stress portion (second part) of the test.
- If you are physically capable and have no contraindications for an exercise treadmill test then you will be asked to walk on the treadmill with gradual increase of speed and incline at 3 minute intervals until your peak of heart rate is achieved.
- If you are not able to exercise, you may be given a medicine/stress agent which is a vasodilator (such as Adenosine or Lexiscan) through your IV. This drug widens (dilates) your heart arteries to help increase blood flow to your heart for the stress portion of the test.
- In other cases, you may get a medicine (Dobutamine) that will make your heart beat faster and harder, similar to when you exercise.
Your heart rate, blood pressure, and heart rhythm (ECG) will be monitored throughout the test. At peak of exercise or vasodilation, a second dose of radioactive tracer is injected through your IV.
During the stress test with these stress agents, you may feel the following:
Dyspnea, jaw and/or chest tightness, head pressure, fatigue, flushing, tingling, lightheadedness, nausea, abdominal cramping. If any of these symptoms occur during your stress test, tell the provider performing the test. These symptoms should subside and resolve within a small timeframe.
After the stress test is completed, you will wait up to 45 minutes prior to returning to the scanner for the stress (second) scan to complete the cardiac nuclear stress test. During this wait, you are allowed to eat and drink.
Typically, your appointment will take about 2-4 hours to complete the study. Some of this time is spent in preparation for the test, and in waiting for the tracer in the bloodstream to be taken up by the heart. There are special circumstances when the procedure may be a two-day study.
Your provider who referred you for the cardiac stress test should receive the test results within 24 hours.