NUCLEAR STRESS TESTING

Other Names: myocardial perfusion scan, myocardial perfusion scintigraphy, Sestamibi stress test; technesium stress stest, myoview stress test 

Description/Test Basics/Reasons for the test:  A nuclear stress test measures blood flow into your heart muscle at rest and during stress (exercise). This test can detect narrowing of the coronary arteries (the arteries that supply blood directly to the heart).  It is performed similar to a routine exercise stress test but incorporates an imaging modality/image-taking of the heart in addition to the stress electrocardiograms. (Please see stress test description)

During a nuclear stress test, a radioactive substance, or energy emitting isotope, is injected into your bloodstream. This substance is carried through the bloodstream into your heart muscle. A special scanner, the nuclear camera, detects the radioactive material in your heart and uses that information to construct images of your heart. These images are displayed on a computer monitor.  The area of the heart that has normal blood flow will receive larger amounts of radioactive substance and therefore appear brighter than areas with lesser or inadequate blood flow, because not as much of the radioactive substance reaches the heart muscle.

Myoview stress test is a nuclear imaging method that shows how well blood flows into the heart muscle, both at rest and during activity (stress).

Test preparation/pre-test guidelines:

  • Pregnant women should check with their physician before engaging in a nuclear stress test.
  • Nothing to eat or drink for a minimum of 5 hours prior to the test.  Should you chose to eat something at that time, it should not be “heavy”- by this we mean something light such as a small amount of oatmeal, a slice of toast, a small amount of juice for example. 
  • No smoking or tobacco products the day of the test. 
  • Please do not exercise for at least 8 hours prior to the stress test.
  • Wear loose, comfortable clothes in which to exercise and walking shoes with non-skid soles. Since your blood pressure will be checked periodically during the test, a short-sleeved shirt or blouse is preferred.  Do not wear boots, jumpsuits, overalls, or a dress.
  • Do not take any medications the day of the test.  Bring all your medications with you.  Medications used to treat asthma and angina may interfere with test results. Never stop taking any medicine without first talking to your doctor.
  • No caffeine 24 hours prior to the test.  This includes caffeinated beverages such as tea, coffee, and sodas, as well as chocolates, and certain pain relievers and cold remedies.
  • The test will take 3-4 hours and we highly recommend reading material.  Family and friends are welcome in the office but will be asked to remain in the waiting room to limit their radiation exposure.

Test process/How the test is done: Prior to the test, ten electrodes will be placed on your chest just as they would be for an electrocardiogram (ECG) or regular stress test. The nurse or technician will start an intravenous line, or IV, line in your arm most likely. You will then be given your first dose, or “resting dose” of myoview, the radioactive substance, via the IV line that was set up. Per protocol, you will wait for a minimum of 30 minutes before your first scan on the nuclear camera. The camera will take 13 minutes to complete a series of scans/pictures of your heart.  A computer creates pictures of the heart by tracking how the radioactive material moves through the area.

The next phase of the test is your stress test.  As described in detail on the stress page, the patient will perform a “graded” exercise treadmill test.  If the patient cannot walk on the treadmill for any reason, the patient will be given the vasodilator adenosine which simulates the effects of exercise.
 Recordings of the heart's resting activity are made before exercise begins, including heart rate, blood pressure and ecg. The patient begins the stress test by walking slowly on a treadmill. The speed and incline of the treadmill typically increase every 3 minutes to raise the patient's exertion level and increase the work the heart must do. The physician or technician may stop the test at any time for medical reasons or you may stop the test because of significant fatigue or discomfort. In general, however, we encourage you to exercise as long as possible in order to maximally stress the blood flow to your heart.  Exercise typically lasts from 5 to 15 minutes. When the person's maximum predicted heart rate has nearly been reached, or about 75 seconds before the patient needs to stop exercising, the radioactive tracer myoview is injected into the patient's bloodstream through the IV line.  This second dose of myoview is referred to as your “stress” dose. The person continues exercising for about 1 minute to allow the myoview to circulate through the bloodstream and into the heart. Myoview  is absorbed by the heart muscle in proportion to the blood flow to it through the coronary arteries. The stress test is completed and the patient is monitored to ensure their heart rate and blood pressure are normalizing.  You will also be required to drink a minimum of three cups of water. The water helps clear out activity in the stomach and colon, or “gut”, which might obscure the images of the heart. The patient is then placed back on the nuclear camera which detects the radiation being emitted by the myoview as it progresses through its series of scans.  The camera will take 13 minutes to complete a series of scans/pictures of your heart. After you leave the laboratory the technician will “process” the pictures in order to compare the blood flow patterns at stress and rest. The technician's have undergone special training to do this.

The entire test can take about 4 hours. You will be given breaks in between scans.  It is recommended you bring reading material with you.

Post-test guidelines: Most patients resume normal activities immediately following nuclear stress testing.  Patient's will be asked to refrain from taking a shower for a minimum of 6 hours after the stress test and drink plenty of fluids to flush the myvoiew out of their system


Test location: Your stress test will be performed at our main office, located in Denton, Texas:   
 

The Heart Center of North Texas
3304 Colorado Blvd.
Suite 101
Denton, TX 76210




HOSPITAL PRIVILEGES:   •  Denton Regional Medical Center   •  Texas Health Presbyterian Hospital Denton
   •  Muenster Memorial Hospital   •  North Texas Medical Center


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