How Does It Work?
A stress test forces the heart to work harder while measures of heart function are monitored. This test can tell doctors if part of the heart muscle is not receiving enough blood due to blockages in the heart (coronary) arteries, if heart valves may not be working correctly, or if a procedure to treat heart disease was successful, among other things.
The test involves asking a patient to exercise on a treadmill or stationary bike, or take medications that will make the heart respond as if the patient is exercising. During exercise, heart function is monitored by an electrocardiogram (ECG or EKG) machine that measures the electrical impulses in the heart. Common medications used for medication (pharmacological) stress tests include dipyridamole, dobutamine and Adenosine.
How Is It Performed?
During a stress test, you will be asked to walk on a treadmill or take medications to make your heart simulate the work it does with exercise. Be sure to follow any food and drink guidelines that your physician gives to you to prepare for the test. Wear shoes and clothing that are appropriate for walking on a treadmill.
While you walk, electrodes (sticky patches) that are attached to your chest and limbs send signals to an electrocardiogram machine, which creates a readout of heart activity. The continuous recording from the electrocardiogram taken during the stress test evaluates how electricity flows in the heart and any changes consistent with a portion of the heart not receiving enough blood flow. Whether you feel chest pain or other symptoms when your heart is “under stress” may indicate to your doctor the presence of any blockages in the arteries that supply blood to your heart.
In addition to the continuous recording of the electrocardiogram, your doctor may obtain images during the stress test through an echocardiogram (ultrasound) to assess the flow of blood. You may also receive a nuclear stress test, for which a small amount of radioactive tracer will be injected into your bloodstream. These imaging tests may be needed for some patients to increase the accuracy of the stress test.
Is It Safe?
A stress test is a very safe diagnostic tool. You will be closely monitored during the test to keep exercise within safe limits. Very rarely, a person can have a heart attack during a stress test. Some patients may also experience low blood pressure or abnormal heart rhythms (arrhythmias) that usually resolve soon after the test is complete. Also, certain medication stress tests may make you feel short of breath or flushed for a short time.
Questions to Ask Your Doctor About Stress Tests
The following questions can help you talk to your physician about having a stress test. Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
- What can a stress test tell us about my heart health?
- What type of stress test will I be having?
- Will my stress test be an exercise test or will I be asked to take medications to make my heart work harder?
- Do I need to have an empty stomach before the procedure? Should I withhold any of my medications?
- How accurate is a stress test?
- What happens next if my stress test shows that my heart is not receiving enough blood or is not functioning properly?
Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.
Another resource you may find helpful was developed by Choosing Wisely and SCAI, the organization that hosts this website. We invite you to download Stress Tests After a Stent Procedure: When You Need Them – And When You Don’t.