Nuclear Stress Test

Frequently Asked Questions Regarding Ultrasound

Myocardial Perfusion Imaging stress testing is usually done in nuclear medicine departments of a hospital or in cardiac clinics. The test may be performed on an out-patient or inpatient basis. The test involves an injection of radioactive pharmaceutical, a clear radioactive diagnostic liquid for intravenous injection. A small amount of this radioactive pharmaceutical is injected into the bloodstream, where it is taken up into the heart muscle. A special camera is used to take pictures of the heart. From those pictures, your doctor can determine the blood flow to the heart muscle as well as additional structural information about the heart.

*WARNING: *Radioactive pharmaceuticals should not be given during pregnancy unless the potential benefit to the mother outweighs the potential risk to the unborn child. *Radioactive pharmaceuticals may be given to nursing mothers; however, formula should be substituted for breast milk until the radioactive component has cleared the body. Safety and effectiveness in pediatric patients has not been studied..

The radiopharmaceutical stress tests are indicated when your doctor needs to evaluate for example:

  • How well your heart responds to exercise.
  • The cause of your chest pain.
  • The degree of blockage in your coronary arteries.
  • How well a heart procedure done to improve blood flow in your coronary arteries is working.
  • Irregular heart rhythms.

There are several reasons you may be asked to have a stress test:

  • Your doctor suspects you may have heart disease and wants to confirm it Your doctor can suspect coronary artery disease if you have chest pressure or other symptoms.  Having certain risk factors such as high blood pressure or family history of heart disease could increase your chance of having coronary artery disease.  It’s important to be tested, because people with heart disease feel no symptoms at all.
  • Your doctor already knows you have heart disease and wants to monitor your condition. If you have already been diagnosed with heart disease, your doctor may ask for a stress test to:  look for any heart damage you may have, track the progress of your condition and assess your risk for problems in the future, and determine how well your treatment is working.
  • To provide your doctor with information about how well blood is flowing to your heart and how well your heart is working.

The test usually consists of two parts:  after exercising and under resting conditions.  There are many variations for performing the test, which depend on the department’s routine.  The entire test may be completed in one day or on two separate days.  You will be informed if the exercise or test portion will be done first.  Radioactive pharmaceutical will be administered by injection during peak stress and once again while you are at rest.

As in a regular stress test, ECG electrodes will be attached to your chest.  This will allow your physician to monitor your heart rate before, during, and after exercise.  A blood pressure cuff will be placed on your arm to monitor your blood pressure before, during, and after exercise.  Additionally, an intravenous(IV) line will be placed in a vein in your hand or arm to allow for ease of the radioactive pharmaceutical injection.  The IV will be removed when the exam is completed.

The exercise part of the exam is usually done with a treadmill, very similar to a treadmill used at a health club.  Exercising will begin slowly, and approximately every three minutes, the pace will increase.  As you exercise, your heart rate and blood pressure will change.  This is normal, and remember, you are being closely monitored throughout the exam.  At your peak exercise, radioactive pharmaceutical will be injected in the IV, and you will be asked to continue exercising for an additional one to two minutes.

Approximately 15-45 minutes after the exercise is completed, pictures will be taken of your heart using a special camera able to trace the radioactive pharmaceutical that has localized in your heart.  You will lie down on a special table.  The camera will rotate above and around your chest while special pictures are being taken, which will take approximately 20 to 30 minutes to complete.  You may breathe normally while the pictures are being taken.  It is very important that you hold very still while the camera takes the pictures of your heart.  You will not receive any radiation from the camera.

The resting pictures are taken in the same manner as the exercise pictures.  Remember, the order in which pictures are taken depends on the department’s imaging procedure.  The total time needed for the test varies and may take from two to five hours.

Some people, because of a variety of disabilities, are unable to exercise adequately on a treadmill machine to achieve a diagnostic test result.  In these cases, your doctor may decide to use a pharmacological stress agent to stimulate the effect of exercise stress on your heart.  These drugs are usually injectable medications.  After they are injected and they begin to take effect, a radioactive pharmaceutical is also injected into the bloodstream via the IV line.  After about 25 to 60 minutes, you will be placed on a special table where a camera will take pictures of your heart.  In some cases, your doctor may require you to perform exercise such as squeezing a rubber ball or other mild, small movements while the pharmacological stress agent is being injected and after the radioactive pharmaceutical is administered.  It is important to avoid all caffeine intake for 24 hours prior to the test; do not drink coffee, tea, colas or other soft drinks, or eat chocolates, including candies, frosting, cookies, pies, cocoa, or chocolate milk for 24 hours prior to the test.

Patients are allowed to maintain normal activity after there test is complete.

The entire nuclear imaging test may last 2-3 hours or longer, so you will need to plan accordingly.
There may be two parts to the exam, in which you will need to return to the office for the second part.

Yes, your doctor must provide a referral (prescription) in order for you to receive a examination.  In addition, some insurance carriers or HMO’s require a pre-certification.  Please discuss this with your doctor and your insurance company or HMO prior to your test.

A Cardiologist will review your study the same day and a written report will be available within 24 hours.  A detailed written report of the procedure, findings, and results will be sent to your physician within 24 hours.  Your physician will then call you to discuss the results.  Urgent results will be telephoned immediately to your doctor.

Normal Values:
When a normal amount of the radiotracer arrives into all areas of the heart, the heart images are obtained are normal.  The heart images at peak exercise are compared to the heart images at rest.  If during both exercise and rest all images are normal, then your blood flow through the coronary arteries is considered to be normal.

Abnormal Values:
In your heart pictures, an area may lack the radiotracer and thus show a spot of a different color, called a ‘defect’.  Defects represent poor uptake of the radiotracer by the heart because of reduced blood flow.
When a defect occurs at peak exercise and not at rest, the most likely cause is a significant blockage of a coronary artery.  When a defect is observed both at rest and with exertion, that indicates that previous damage from a heart attack has occurred and that the heart has a scar.

Any stress procedure may have some risks, and you should consult with your physician regarding the risks and benefits of this procedure.  Radioactive pharmaceuticals that are used have been shown to have an excellent safety profile, with a low incidence of adverse reactions.  Radiation exposure from a myocardial perfusion study using radioactive pharmaceuticals is very slight.  The most common patient complaints include:  chest pain, flushing, shortness of breath, abdominal pain, headache, dizziness, and abnormal taste sensations.  On rare occasions, patients receiving radioactive pharmaceutical injections have allergic side affects including skin rashes, blurred vision, and fever.  Please inform the technologist of any side affects you may experience during the exam.

You will be instructed to wear comfortable clothes and shoes with non-skid soles.  Please do not wear dresses, skirts, or shoes with heals.  You will probably be asked not to eat or drink anything for 4 hours prior to the exam, except for a few sips of water if you need to take medication.  Please refrain from wearing any cologne or perfume the day of the exam.

NO CAFFEINE FOR 24 HOURS PRIOR TO EXAM:
For one entire day prior to the test, you will be required to abstain from caffeine and certain medications.  Caffeine is in food and beverages such as all regular and decaffeinated coffees and teas, chocolate products, many sodas, and certain pain relievers.  These are just a few examples.  Please read the labels of your food and beverages carefully, because caffeine consumed before the test may invalidate the test results.

Medications that you may need to stop taking before the test include some asthma  medications and medications for chest pain (angina); check with your doctor.  If you take insulin to control your blood sugar, ask your physician if or how much insulin you should take the day of the test.  Please do not wear nitro patches, they will have to be removed and thrown out, but please bring them with you for after the exam.  If you take medication to control your blood pressure, please bring them with you to take them after the exam.

The entire nuclear imaging test may last 2-3 hours, so you will need to prepare accordingly.  At some point during your stay for the test you will likely be given a long break and be allowed to have a snack.  Please bring a snack with you.  During this test you will not be sedated and therefore once the test is completed you will be able to drive yourself home.