Stress / Echo
Some patients have blocked coronary arteries that cannot be detected until the heart muscle is exercised (stressed). During exercise, normal arteries will expand (dilate) to permit more blood to flow to the heart. However, blocked arteries are not able to expand as much as normal arteries. So, when the heart muscle is exercised and calls for more blood flow, a blocked artery may be unable to provide enough needed blood. When this happens, symptoms may occur including chest pain, shortness of breath, abnormalities in the electrical activity of the heart, or changes in the way the walls of the heart move. A stress echo/test is designed to identify those symptoms of a blocked coronary artery. A stress/echo test is, as the name suggests, the combination of a cardiac stress test and an echocardiogram.
Purpose of the Procedure
A stress echo test is used to compare the functioning of the heart before and after exercise and in particular to identify any abnormalities in the functioning of the heart that would indicate that one or more coronary arteries may be partially blocked or that there is a problem with a heart valve.
Before the Procedure
Before the stress echo test, you should receive an explanation of the procedure and the benefits and risks, and you will be asked to sign medical consent forms to authorize the procedure and acknowledge that you understand the risks. Be sure to ask any questions you may have about the procedure and why it needs to be performed. The more you understand, the better. You will also be asked about your medical history and any symptoms you have been feeling. Please be sure to talk to your doctor about whether or not you should take your medications prior to a stress echo test. In particular, blood pressure medications can impact the results of a stress echo test, so if you take this type of medication, please ask the doctor if you should stop taking it prior to the procedure. Diabetic patients should also discuss with their doctor or nurse any special instructions about insulin intake prior to the procedure.
Because the test involves strenuous exercise, you should avoid eating or drinking 6 hours prior to the test to minimize the possibility that you may feel nausea or cramping during the exercise portion of the procedure.
You should wear comfortable clothes and shoes suitable for walking or jogging. You will be asked to remove your shirt for the procedure. Women will need to remove their bra due to imaging and will be provided with a hospital gown. You should be sure to tell your doctor, nurse, or the hospital if you have asthma, chronic lung problems, or frequent periods of shortness of breath. If you weigh more than 350 pounds or you have difficulty walking more than six city blocks, you should also alert the doctor, nurse, or hospital staff before you arrive for your procedure.
During the Procedure
The equipment used for a stress echo test includes an electrocardiograph (a machine used to measure the electrical activity of the heart), echocardiograph (a machine that uses sound waves to produce an image of the heart in motion), computer, blood pressure cuff and stethoscope, and an exercise machine (usually a treadmill). A specially trained technician, a nurse and a specially trained echocardiographer will usually conduct the test.
You will first be asked to remove your shirt and the nurse or technician will clean and shave (if needed) several small areas on your chest, arms, and legs. A small electrode will be placed on each area and wires to the electrocardiograph will connect each electrode.
Either immediately before you are hooked up to the electrocardiograph or immediately following, the technician will ask you several questions including your name, height, weight, and current medications. This information will be entered into the computer to calculate your maximum heart rate. The technician will monitor your heart rate throughout the procedure to make sure it does not exceed the maximum rate.
After the information is collected and input into the computer, the technician will measure your resting heart rate and blood pressure, and also perform an initial electrocardiogram to trace the electrical activity of your heart at rest. Then you will be asked to lay down on your left side and an initial echocardiogram will be administered (sometimes, the echocardiogram is performed before the electrocardiogram). The echocardiographer will apply gel to your chest to assist the machine to collect a good image of your heart in motion. The echocardiographer will then place a small wand called a transducer into the gel and by moving the wand around the chest, an image of the heart will be generated and displayed on the video monitor included in the echocardiograph. You will also hear the amplified sound of your heart beat which the echocardiographer uses to detect abnormalities in the heart valves. During the echocardiogram, you may be asked to change position, hold your breath, or take other actions. This aids the echocardiographer to create the most accurate image possible. As soon as your initial echocardiogram (called the resting echocardiogram) is completed, you will be asked to step on the treadmill to begin the exercise portion of the procedure.
At first, the treadmill will move at a very slow rate. Approximately every three minutes, your blood pressure and heart rate will be measured and the treadmill will increase in speed and elevation. At first, it will be as if you are slowly walking on level ground. Then, the speed and elevation will change and you will be walking faster up a small incline. Based upon your physical condition and how your heart rate reacts to the changing speed and elevation of the treadmill, the exercise portion of the procedure may last for just a few minutes or perhaps fifteen minutes or longer. The longer the procedure lasts, the faster the treadmill will go and the higher the elevation. After several minutes, if your heart rate and physical condition permit, you will feel like you are running up a hill. Throughout the procedure, the technician will ask you how you feel. If at any time if you feel severe fatigue, chest pain, or other significant discomfort, you should tell the technician and ask that the procedure stop. The goal of the exercise portion of the procedure is merely to raise your heart rate to near the maximum rate, if possible. Once the heart rate increases sufficiently, or you feel like you should stop, the exercise portion of the exam will be terminated.
Immediately after the exercise concludes, you will be asked to again lay down near the echocardiograph for another echocardiogram. This echocardiogram will be a repeat of the one you were given before the exercise portion of the procedure. The echocardiographer will collect motion images of your heart that will allow the physician to identify abnormalities that appear only after the heart muscle is exercised. Once the second echocardiogram is complete, the procedure is over.
After the Procedure
Following the stress echo test, the technician will remove the wires and electrodes from your chest, arms and legs. You will also be given a cloth or paper towel to remove the excess gel that was used during the echocardiograms. You will then be able to put your shirt on and leave the examination room. No special requirements or restrictions follow a cardiac stress test, but you may feel fatigued from the exercise. You are able to eat or drink as normal following the procedure. Usually, the physician will be able to give you a complete report within a day or two.
Frequently Asked Questions
What is the doctor looking for?
The doctor is looking for abnormalities in the function of the heart that are produced when the heart is exercised or stressed. These may include blocked coronary arteries, problems with heart valves, blood clots, or excess fluid around the heart.
Where are the tests done?
The procedure is performed in the stress lab.
May I eat or drink?
You must not eat or drink at least six hours before the test.
What about medications?
You need to discuss your medications with your doctor or nurse. You should be off Beta Blockers and Calcium Channel Blockers for 24 hours before the test. If you are diabetic, take half of your usual insulin. You may bring the rest of your dose and something to eat or drink if you feel you need it. Do NOT take pill form of diabetes medication unless otherwise instructed. All other medications except those we mentioned may be taken with a sip of water. * If you have any questions, please call your Doctor.
Will I have an IV?
Do I Need Special Clothing?
You should wear comfortable clothing and shoes suitable for walking or jogging.
How Long Does The Test Take?
The entire procedure should last approximately 1 1/2 to 2 hours.
How safe is a stress echo test?
The exercise portion of the test does include some risk due to the nature of exercising the heart muscle, but a stress echo test is considered a relatively low-risk procedure.
How accurate is a stress echo test?
Generally, a stress echo test is considered highly reliable and capable of detecting heart disease in more than 85 percent of patients with coronary artery disease. The actual reliability of the procedure depends on the quality of the echocardiogram images and the ability of the patient to generate a sufficient heart rate during the exercise portion of the procedure.