If you need to cancel your appointment, please do so at least 24 hours prior, or you will be charged $150.00 for nuclear medicine. Call our office at 407-894-4880 to reschedule.

Why Do I Need a Nuclear Stress Test?

A nuclear stress test is performed for the following reasons:

  • To evaluate the cause of chest pain and to rule out coronary artery disease.
  • To determine the ability of the heart to tolerate exercise in people who have had a heart attack or heart surgery.  In these patients, the nuclear stress test can identify new blockages as well.
  • To evaluate abnormal heart rhythm during exercise.
  • To evaluate the effectiveness of the current medical program.
  • To assess blockages after coronary intervention or coronary artery bypass surgery.
  • To screen for coronary artery disease in a high-risk person, such as those with high blood pressure, cholesterol, diabetes, smoking, and a family history of heart disease.

Test Preparation

  • You may take your medications up to the day of the procedure.
  • You will be asked to sign a consent form.  Overall, this is a safe test with less than 1% risk of complications.
  • No caffeine or dairy products after midnight on the day of the test. This includes decaffeinated coffee, butter, milk, and cheese.
  • Do not eat or drink 4 hours before the test.
  • Bring a light breakfast or lunch sandwich and a non-caffeinated drink with you.
  • Wear a button down short sleeve shirt (no metal buttons or zippers) and athletic shoes. Do not wear necklaces.  Women should NOT wear a dress.
  • Stop the following medications 24 hours before the Lexiscan stress test: 

o      Persantine (Dipyridamole)

o      Theophylline

o      Primatene and Theo-Dur

  • Stop the following medications 24 hours before the Exercise stress test:

o      Beta-blockers (Atenolol, Toprol, Metoprolol, Lopressor, Coreg, Zebeta, Betapace, and Corgard)      

What is a Nuclear Stress Test?

A nuclear stress test, also known as a myocardial perfusion imaging stress test,determines if there are any blockages in the coronary arteries more accurately than does a regular stress test.  When a coronary artery has more significant than a 50% blockage in the lumen, there is a potential for decreased blood flow, resulting in chest pain (angina).  Even at rest, a blocked artery can supply enough blood and oxygen to the heart muscle.  However, during exertion, there is a greater demand for oxygen, and this demand may not be met, resulting in chest pain (angina).

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There are two kinds of nuclear stress tests:

EXERCISE NUCLEAR STRESS TEST

The patient will exercise on a treadmill to achieve an age-predicated heart rate, and then the radioactive tracer is injected.  Imaging is then performed under the camera. The two images are then compared and interpreted by your physician (Dr. Jamnadas, Dr. Kelly) to determine if there is any compromise in blood flow.

LEXISCAN STRESS TEST

This is also known as a chemical stress test.  This test involves no exercise and is suited for patients with limited exercise tolerance, joint diseases (arthritis), poor circulation or claudication, stroke victims, or patients with gate disturbances, dizziness, or certain heart rhythms.  Instead of exercise, Lexiscan is injected to induce coronary artery dilation followed by the radioactive tracer injection and scanning.  This test mimics exercise to the body and is well tolerated.  The results are equal to those received in the exercise nuclear stress test.

The nuclear stress test is comprised of two parts:

Part 1:  This is when the resting images are taken.  An IV is started in the                                    arm, and the radioactive tracer is administered.  After a brief wait, you will lay on your back with an arm raised.  The camera will move around your body and capture images of the heart. 

Part 2:  This is when the stress images are taken.  The stress allows the blood vessels to dilate.  This occurs either by exercising on a treadmill or through medication that dilates the blood vessels.  The patient will be connected to an EKG machine to allow monitoring of the heart rhythm. Blood pressure will also be monitored during and after the stress test.  You will be asked to lie on your back with an arm raised as the camera moves around your body to capture the images of your heart.

Risks

·      If you have coronary artery disease, it is possible that you could experience chest pain, when stress due to exercise or a drug is applied to your heart. However, your test will be carried out under the supervision of a specialist trained to monitor you and your heart by using information being provided by the electrocardiogram, by your heart rhythm, and by your blood pressure. If necessary, medication can be given for your chest pain. Occasionally an irregular heart rhythm may develop, but emergency equipment, medications, and trained personnel are always available in the stress lab. Some patients may experience a faint feeling or flushing, but these symptoms are temporary and benign. The drug administered, adenosine, is in the body’s circulation for 4 minutes, and the symptoms (if any) are relieved after these 4 minutes. You will be monitored long enough to ensure that you are at your baseline; that is, the condition you were in when you first came for the test.

·      The use of a radioactive substance will result in exposure to a small amount of radiation to the heart and to the body. However, the amount of radioactivity administered is the smallest amount necessary to provide adequate images. The exposure is less than a dental x-ray, and the half life of the radioactive material is 6 hours.  Cardiac nuclear medicine procedures have been done for more than three decades, and no long-term adverse effects have been reported from such low-dose studies.

·      Allergic reactions to radiopharmaceuticals and adenosine can occur but are extremely rare.

·      As with all radiologic procedures, it is important that you inform your physician and the technologist if you are pregnant. In general, exposure to radiation during pregnancy should be kept to a minimum.

Results

               Your physician will review the test results.  The blood flow to your heart muscle at rest is compared to the blood flow to your heart at stress, whether induced by exercise or by adenosine.  In addition, the heart muscle contractions will be determined; this is called the ejection fraction (EF).  A normal ejection fraction is 55-60%.  This test is able to determine if you have had a previous heart attack.  It can also determine the size of your previous heart muscle damage based on the test results.   With this test, your physician can determine whether you are at risk of future heart attacks, chest pain, or disease.  A normal nuclear stress test carries a good prognosis.

After the Test: Due to company policy, the test results will NOT be discussed over the phone.  During your office visit the test results are reviewed and one of the following will be decided at that time:

1. No further work up needed.

2. A stable cardiac condition will require no change in treatment

3. Intensification of medical treatment

4. Further cardiac evaluation using cardiac catheterization and coronary angiography. 

An invasive procedure is most likely performed in patients who have a high risk nuclear stress test result.  Most patients with a low or moderate risk nuclear test can be managed with a prevention program and medical therapy.

If you need to cancel your appointment, please do so at least 24 hours prior or you will be charged $150.00 for the nuclear medicine. Call our office at 407-894-4880 to reschedule.