Your Health

The team at Salem CardioVascular Associates wants you to be educated about heart health and vascular disease. Every office visit is an opportunity for you to become better informed and to have your questions answered.

• What is Coronary Artery Disease?

  Coronary Artery Disease (CAD) is a condition where there is inadequate blood supply to the heart, usually caused by blocked arteries.

• What is a Myocardial Perfusion Imaging Stress Test?

  A Myocardial Perfusion Imaging Stress Test is usually performed to learn if your heart muscle is receiving adequate blood supply under stress and/or rest conditions. The test is done in a Nuclear Medicine Department or Cardiac Clinic on either an outpatient or inpatient basis. The test involves an injection of a small amount of radioactive material which circulates in the bloodstream followed by taking pictures with a nuclear medicine camera. The radioactive injection is a clear liquid called MYOVIEW (Tc99m Tetrofosmin for injection) or CARDIOLITE. Another material which could also be used is called Thallium.

• How safe is a Myocardial Perfusion Stress Test?

  Any stress procedure may have some risks and you should consult with your physician regarding the risks and benefits prior to having this procedure. The radioactive materials, Myoview, Cardiolite and Thallium, have been shown to be safe with low incidence of adverse reactions. This test and materials are used routinely worldwide, under physician supervision, for myocardial perfusion imaging. Neither Myoview nor Thallium are "dyes," and there should be no serious side effects from their injection.

• Why would my doctor order a Myocardial Perfusion Imaging stress test instead of a regular stress test?

  Under certain circumstances, a regular stress test may yield inconclusive results. To improve the diagnostic accuracy, your physician may request a Myocardial Perfusion Stress Test.

• How is the test performed?

  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 procedure. The entire test may be completed in one day or in two separate days. You will be informed if the exercise or rest portion will be done first. MYOVIEW will be administered by injection during peak exercise and once again while you are at rest.

  To begin the test, ECG electrodes will be attached to your chest. This will allow your physician to monitor your heart rate before, during, and after you have exercised. A blood pressure cuff will be placed on your arm to monitor your blood pressure before, during and after exercise. Additionally, an intravenous (I.V.) line will be placed in your hand or arm vein to allow for ease of the MYOVIEW 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. Exercise begins slowly, with the pace gradually increasing approximately every three minutes. As you exercise, your heart rate and blood pressure will change. This is normal and you will be closely monitored throughout the exam. At your peak exercise, MYOVIEW will be injected into the I.V. You will then be asked to continue exercising for an additional one or two minutes.

  Approximately 30 minutes to 1 hour after the exercise is complete, pictures will be taken of your heart using a special camera able to trace either the MYOVIEW or the Thallium that has localized in your heart. You will be asked to sit in an imaging chair. The chair will rotate around the detector heads and take pictures of your chest. This will take 8 to 10 minutes to complete. 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.

• What happens if I am unable to exercise?

  Some people, due to a variety of disabilities, are unable to exercise adequately on a treadmill machine to achieve a diagnostic test result. In these cases, your physician will give you an injection of Lexiscan to take the place of the treadmill. It has a few side effects which dissipate quickly.

• Are there any special preparations or instructions for the Myocardial Perfusion Imaging study?

  

  CLOTHING - You should wear comfortable, loose-fitting clothing for exercise and comfortable shoes appropriate for walking. Please try to avoid underwire bras and metal on your shirt.

  MEDICATIONS - Consult with your physician regarding whether certain medications should be taken before, or held until after, the test. Certain medications may interfere with the effectiveness of the exam.

  WORK - Depending on the department procedure, time permitting, you may have time to go back to work between the two parts of the exam. The physician will inform you if this is possible.

  Important Points to Remember

  • The test may take place on one or two days, depending on the individual.
  • Both parts must be completed for obtaining results.
  • You will receive an injection for both parts of the exam.
  • The radioactive material is ordered especially for you. If you are unable to keep your appointment for any reason, notify us at 503-585-5585 before the exam.
  • A written report of the test will be sent to your physician once it is interpreted.
  • If you are pregnant or suspect you may be, notify your doctor before taking the test.

  Please note that this information is provided for educational purposes only. It is not intended to substitute for informed medical advice. The user of this site should not use this information to diagnose or treat a health problem or disease without consulting with a qualified health care provider.

• How does an Isotope Stress Test Work?

  An isotope stress test is also known as a nuclear, thallium, Cardiololite, Myoview or dual isotope stress test, depending upon the method used.

  During exercise, healthy coronary arteries dilate (develop a more open channel) more than an artery that has a blockage. This unequal dilation causes more blood to be delivered to heart muscle supplied by the normal artery. In contrast, narrowed arteries end up supplying reduced blood flow to its area of distribution. This reduced flow causes the involved muscle to "starve" during exercise. The "starvation" may produce symptoms (like chest discomfort or inappropriate shortness of breath), and EKG abnormalities. When a "perfusion tracer" (a nuclear isotope that travels to heart muscle with blood flow) is injected intravenously, it is extracted by the heart muscle in proportion to the flow of blood.

  The amount of tracer uptake helps differentiate normal muscle (which receives more of the tracer) from the reduced uptake demonstrated by muscle that is supplied by a narrowed coronary artery. In other words, areas of the heart that have adequate blood flow quickly picks up the tracer material. In contrast, muscle with reduced blood flow pick up the tracer slowly or not at all. Analysis of the images of the heart (taken by a scanning camera) can help identify the location, severity and extent of reduced blood flow to the heart. The reduced blood flow is known as ischemia (pronounced is-keem-ya).