A cardiac stress test is one of the basic examinations used to diagnose conditions such as coronary artery disease, arrhythmia or irregular heart beat, or to check on the effectiveness of balloon angioplasty procedures or coronary artery bypass surgery.
Stress tests are non-invasive and relatively low risk procedures whereby the heart muscle is exercised so that the electrical activity of the heart may be monitored under conditions of physical stress. Often, it is possible to discover heart problems while the heart is stressed, whereas those conditions may not be apparent at other times. A cardiac stress test will often be ordered by your physician when you have experienced symptoms such as chest pain and shortness of breath, signs that your heart is not getting enough oxygen, or signs that you may be at risk for a heart attack.
Purpose of the Procedure
A cardiac stress test is used to compare the functioning of the heart before, during, and after exercise and in particular to test how well the heart muscle functions as it is increasingly stressed. The test itself is simply another type of electrocardiogram where the patient exercises to increase their heart rate.
Before the Procedure
Before the cardiac stress 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 cardiac stress test. In particular, blood pressure medications can impact the results of a cardiac stress test, so if you take this type of medication, please ask the doctor if you should stop taking it 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 test includes an electrocardiograph (a machine used to measure the electrical activity of the heart), computer, blood pressure cuff and stethoscope, and an exercise machine (usually a treadmill). A specially trained technician and a nurse 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. A small electrode will be placed on each area and wires to the electrocardiograph will connect that 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. Once that is completed, you will be asked to step on the treadmill and exercise will begin 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 enter a “cool down” period that will last several minutes. Then, the technician will again perform an electrocardiogram to measure the electrical activity of the heart following exercise. The electrocardiogram performed following the exercise will be compared with the one performed before the exercise. This will provide the physician with information about how your heart reacts under stress.
After the Procedure
Following the cardiac stress test, the technician will remove the wires and electrodes from your chest, arms and legs. 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. Normally, the physician will be able to give you a complete report often on the same day or within a day or two.
Frequently Asked Questions
What is the doctor looking for?
How the heart pumps during exercise.
Where are the tests done?
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?
Approximately 1.5 hours.