Exercise Stress Test
What is an Exercise Stress Test?
An Exercise Stress Test or exercise stress ECG is a walking treadmill test usually performed help diagnose significant coronary artery disease, however it can also assist in the investigation of abnormal heart rhythms.
Testing for Coronary Artery Disease
Coronary artery disease is a result of blockages within the coronary arteries, the vessels that supply blood to the heart muscle (myocardium). If a partial blockage is present, the heart muscle may still receive an adequate supply to meet its needs at low levels of exercise, and therefore remain undiagnosed. During exercise, the heart requires more blood and partially blocked arteries may not be able to supply the amount of blood required, resulting in a lack of oxygen to the heart muscle (ischaemia). Ischaemic heart muscle may cause chest discomfort (angina) and shortness of breath. There may be characteristic changes on the electrocardiogram (ECG). These ECG changes along with other clinical information is how the test is interpreted.
Testing for Cardiac Arrhythmias
Some heart rhythm disturbances only occur when exercising, so a stress test may be conducted in order to reproduce abnormal heart rhythms so a diagnosis can be made. Patients with programmable pacemakers may also require a stress test so that their Cardiologist can check that the pacemaker responds properly as the patient is exercising.
How do I Prepare?
You will be required to wear comfortable walking shoes and fast for 2 hours prior to the test. Take your medicine as usual unless you are told otherwise by your doctor. A gown will be available but it may be advisable to wear shorts or a skirt to walk in. You may have a shower following the test if you wish.
What Should I Expect?
The ECG electrodes will be applied to the skin at specific places across your chest, and you will have a blood pressure cuff on one arm. After some initial baseline recordings and measurements the Cardiologist will then supervise the test.
The exercise stress test is performed using a standardised, multi-stage protocol for assessing cardiac health, that takes into account the patient’s individual characteristics:
- The standard Bruce protocol (called the ‘Bruce Protocol Stress Test’) is for patients of average fitness
- The Naughton protocol (which is a slower and flatter walk) for less fit or frailer patients
- The accelerated Bruce protocol is for fit patients.
The test will start with an easy walk and then progress every 1-3 minutes with an increase in speed and slope depending upon your level of fitness. Your electrocardiogram (ECG) and blood pressure are continually monitored throughout the test.
The stress test continues until the highest level of activity you can complete before stopping due to fatigue, or symptoms (chest pain, shortness of breath, or light-headedness), or until changes in the ECG or blood pressure indicate a cardiac problem. After the test, you will remain monitored until any symptoms resolve, and the ECG and blood pressure return to a normal resting state.
This is a very low risk procedure. The most common risks include:
- Chest pain which can be treated by stopping the test and administering medication.
- An abnormal heart beat or “arrhythmia” which may be treated by stopping the test and may also be treated with or without medication.
- Serious risks including heart attack or dangerous arrhythmia may occur at a rate of 1 in 10,000 people.
If you have a history of previous/recent heart attack, aortic dissection, recent fluid or clots in the lungs, severe heart valve disease, heart arrhythmias, palpitations, or recent increase in chest pain you should advise the staff before you commence the test. You will also be asked to provide a list of your medications so that these can be noted prior to the test.
Exercise Stress Test Results
A report will be generated by the Cardiologist, this will than go to your referring Doctor, usually on the same day or overnight. You should contact your referring Doctor for your results and any follow up required.