Pharmacologic Stress Testing

GENERAL INFORMATION:

What is pharmacologic stress testing? Pharmacologic stress testing is also called a chemical stress test. This test uses medicine to make the heart work just as it does when you exercise. The medicine works on the blood vessels or muscles of the heart, and is safe to use as a heart stressor. Stress makes the heart work double time so that it sends more oxygen-rich blood to the body. Arteries (blood vessels) of the heart that are blocked or damaged cause the heart to work even harder. Blocked or damaged arteries cause symptoms such as chest pain, shortness of breath, tiredness, dizziness, and weakness. Pharmacologic stress testing may show changes in the activity of your heart at rest and while doing heavy work.

Who may need pharmacologic stress testing? The chemical stress test is done to those who have heart-related symptoms but cannot do an exercise stress test. They may be any of the following:

• Elderly people who may have blocked arteries in the heart.
  
  
• People scheduled to have major surgery.
  
  
• People having a chronic (long-term) or long-standing disease with heart problems.
  
  
• Younger people who may have heart disease but also have bone, joint, muscle, or nerve problems.

Why is pharmacologic stress testing done? Your caregiver may ask you to have this test to learn how healthy your heart is. It may find changes in the rate, rhythm, and other activity of your heart, and show heart conditions. These heart conditions may include problems with the arteries of your heart and arrhythmias (abnormal heartbeats). This test may also help your caregiver decide if you can have surgery for other medical problems.

What types of medicine are used to do pharmacologic stress testing? There are two groups of medicine that may be used during a pharmacologic stress test. Your caregiver may choose from the following:

• Medicine that works on the heart muscles: These medicines include dobutamine and arbutamine. They work by increasing the activity of the heart muscles. The contractions (pumping) of heart muscles are made stronger and faster to increase the heart rate. An increase in the heart rate will cause an increase in the blood flow.
  
  
• Medicine that affects the blood vessels of the heart: These medicines include dipyridamole and adenosine. They work directly on the blood vessels of the heart. The arteries are made to dilate (widen) so that there will be more blood flow. More blood flowing in the blood vessels carries more oxygen to the tissues of the body.

How is pharmacologic stress testing done? Pharmacologic stress testing can be done in a clinic, a caregiver's office, or in a hospital.

• An intravenous (IV) line is placed in a vein of the arm.
  
  
• Electrodes (sticky patches) are stuck on your chest. If you have hair on parts of your chest or back, it may need to be shaved to help the patches stick to your skin. The electrodes will be attached to wires that send the electrical activity of your heart to the electrocardiogram (ECG) monitor.
  
  
• A baseline tracing of the heart while you are resting will be recorded.
  
  
• Your caregiver will decide on the type of medicine to be used for your test. The medicine is given slowly by a caregiver through the IV, or a pump may be used.
  
  
• Several ECG tracings will be recorded during and after the medicine is given to you.
  
  
• You may need to do mild exercise on a treadmill after the medicine is given. This is to have an ECG tracing recorded that may be used to compare with the tracing done while you were resting.

Who may not have pharmacological stress testing?

• People having asthma attacks.
  
  
• People who used medicine that contains dipyridamole within the last 24 hours. Dipyridamole is a blood thinner. Ask your caregiver for more information about medicines that may contain dipyridamole.
  
  
• People who have had food or drinks that contain caffeine within the past 12 hours. This includes chocolate, coffee, tea, or sodas.
  
  
• People who have a heart rate of 40 beats per minute or less.
  
  
• People who have a systolic blood pressure number of less than 90 millimeters mercury (mm HG). The systolic number is the top number of a blood pressure reading.
  
  
• People who have uncontrolled hypertension (blood pressure more than 200/110 mm HG).

CARE AGREEMENT:

You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.

Copyright © 2008 Thomson Healthcare Inc. All rights reserved. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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