What to Expect During a Nuclear Stress Test?
A nuclear stress test, also known as a myocardial perfusion scan or persantine thallium test, is a diagnostic exam that assesses the flow of blood to your heart and how your heart pumps while you are under stress. The test is performed by injecting a small amount of radioactive substance into your blood stream and taking pictures of your heart using a specialized camera.
What Happens Before the Test?
Before the test, you will need to stop taking certain medications, including those that slow your heart rate, such as beta-blockers, on the day of the test. Your doctor will inform you about which medications you need to stop taking.
- Arrive 2 hours prior to the test time
- Change into a comfortable outfit and go to the bathroom before arriving
- Avoid food and water for at least 3 hours prior to the test
During the Test
The test consists of two phases:
Contents
Phase 1: Resting Images
- You will lie down on an exam table, and a gamma camera will be placed above you.
- The gamma camera takes images of your heart for 10-30 minutes to create a picture of your heart at rest.
- The radiation injection (technetium) is administered intravenously during this phase.
Phase 2: Stress Images
- The stress portion of the test is designed to mimic physical activity. For this part, you may either walk on a treadmill or take medication that simulates the effects of exercise, such as adenosine or dobutamine.
- You will wear a heart monitor to measure your heart rate and blood pressure during this phase.
- More gamma camera images of your heart will be taken while you are exercising or during the simulation.
- The exercise/stress part of the test usually takes around 20-40 minutes to complete.
Post-Stress Relaxation Period
- After the stress portion, you will sit quietly for 5-10 minutes to allow the technetium to reach its highest level.
- The gamma camera takes final images of your heart during this time.
After the Test
- You may go back to your normal daily activities, including driving.
- If you underwent a treadmill exercise, you can start walking after about 1 hour, as long as you’re not experiencing any chest discomfort, shortness of breath, or severe fatigue.
- You can return to your medications that you stopped taking before the test.
- The doctor’s office or hospital will usually call with the test results within a few hours to a day or two, depending on the radiology facility.
Potential Complications
- Arrhythmias: An abnormal heart rhythm, which usually resolves itself once the radiation is out of your body.
- Risks associated with stress medication: Rare side effects such as chest pain, headaches, and heart palpitations may occur. These symptoms typically resolve within a few minutes of discontinuing the medication.
What Do the Results Show?
The images taken during the nuclear stress test are used to create maps of blood flow and cardiac function. A nuclear medicine technician or a radiologist interprets the images and can identify any areas of:
- Reduced blood flow, which can indicate blockages in the coronary arteries (CAD)
- Areas of increased damage (infarcted myocardium), indicating past or current heart attack
Your doctor will explain the test results, explaining any abnormal findings, potential dysfunctional areas of the heart, and correlation with clinical symptoms and past medical history.
By understanding what to expect during a nuclear stress test, you can feel more comfortable and prepared for this essential diagnostic tool in determining your heart’s health. If you have any further questions or concerns, it is always best to consult your doctor or the healthcare professional performing the test.
