What is this test?
A stress test (sometimes called an exercise electrocardiogram) measures the heart’s response to an increased demand for oxygen. The patient is placed on either a treadmill or exercise bicycle. Slowly, the incline of the treadmill, or the resistance of the bicycle is increased, resulting in an increased workload for the heart. The patient’s heart rate, blood pressure and heart rhythm are continuously monitored during the test.
Why this test may be performed
A stress test is performed to evaluate how the heart will respond to increasing demands for oxygen. It is used to assist the physician in diagnosing the cause of chest pain, to determine how well the heart is working after a heart attack, to assess the effectiveness of prescribed medications, to identify irregularities in the heart rhythm that may occur with increased stress, and to help in the development of a rehabilitation program for someone who has suffered a heart attack or who has existing heart disease.
What this test involves
A stress test can be performed in the cardiology suite or doctor’s office. A physician is usually present or readily available during this exam. Before the test begins, electrodes are placed on the chest and secured by a vest or belt to prevent them from falling off during the test. A blood pressure measurement is obtained and the blood pressure cuff remains on the arm, so that the blood pressure can be measured during exercise. An electrocardiogram is performed before the test begins. Testing begins by having the patient begin to walk slowly on the treadmill or pedal lightly on the stationery bicycle.
After several minutes, the speed and incline of the treadmill are slowly increased at periodic intervals. If you are using a stationary bicycle, the resistance will be increased at periodic intervals. As the intensity of your exercise increases, so does the heart’s demand for oxygen. You will be instructed to report any symptoms that might occur during this test. For example, if you develop chest pain, dizziness, shortness of breath, or extreme fatigue the test will be stopped. At frequent intervals during the test, your blood pressure and electrocardiogram tracing will be recorded. A physician then analyzes this information. A stress test can last for several hours, although you will only be involved in the actual exercise portion of this test for less than 15 minutes. The patient is advised to avoid smoking, eating and drinking for about 4 hours before the test. Wear comfortable shoes, suitable for walking.
What are the risks/precautions for this test?
A stress test is a non-invasive test. Because this test places added stress on the heart, it may compromise the flow of blood and of oxygen to the heart muscle itself. On rare occasions, the extra stress may cause a heart attack or abnormal heart rhythm.
If you are undergoing a stress test, it is imperative to alert the doctor immediately should you develop any chest discomfort, dizziness, shortness of breath or extreme fatigue. The test will be stopped if these symptoms occur. A physician should be present during this exam and emergency equipment should be readily available in the event that the patient develops any complications during a stress test.
What the results may tell you
A stress test allows the physician to evaluate your heart’s function in response to physical stress, when increased demands for oxygen are occurring. Since heart disease may produce no symptoms until it becomes quite severe, an abnormal stress test suggests that one or more of your coronary arteries may be narrowed. A stress test can also identify abnormalities in the heart’s rhythm that may occur only with activity. Following a heart attack, a stress test can provide information about which type of exercise is recommended for rehabilitation of the heart and what type of exercise may result in further injury and therefore should be avoided.