Stress Electrocardiogram

What is an Exercise Stress Test An Exercise ECG/Stress test is a very frequently used test to assess multiple cardiac conditions. It is very important to assess the hearts response to exercise to check adequate blood flow, symptoms reproduced by exercise, palpitations, blood pressure and to monitor patient’s progress over time. We often check patient’s progress after a bypass operation or coronary artery stenting and an exercise test is easy, safe and non-invasive.The aim is to increase the heart rate and put the heart under stress. Most times this is done using a walking treadmill.

After the ECG is checked and blood pressure done the test will begin with a very slow walk. This walk is manageable my almost all people of all ages and is usually possible even in people with walking difficulties. There are various protocols we use but by far the most common is called a “Bruce Protocol” test whereby the speed and slope of the treadmill increases every 3 minutes. It is not a fitness test and the test is stopped by you if asked or by us if a target heart rate is reached, symptoms are experienced, or we see abnormalities on the ECG tracing. Your test will be supervised at all times by an experienced Cardiac Technician and by a doctor.

How accurate is the test?

Exercise testing is mostly done to evaluate patients with chest pain and to look for blockages in the coronary arteries. A treadmill test will in no way rule out plaque (hardening) in the artery unless it is to the extent that is limiting blood flow down the artery. If there is significant numbers of blockages/narrowing’s, or narrowing’s in the main artery of the heart, the test is very accurate, probably over 90%. If there are minor narrowing’s in a single artery, the accuracy drops to about 60%. There is also a high degree of false positives (abnormal stress test result suggestive of blocked arteries but on further testing all arteries are normal), especially in woman. This is one reason that it is far more likely you will actually have an Exercise Echocardiogram, as discussed in that section.

How is an exercise test done?1 ECG electrodes are attached all over the front of your chest. To get better quality tracings the skin in these areas is rubbed a little and in men their chest may require minor shaving in select areas to get the ECG dots to stick. In Ladies, it is advised to wear two piece clothing so that the top can be removed but you will wear a gown whilst walking.

2. The ECG dots are connected to the ECG computer and a baseline tracing will be done to ensure there is no danger to having the test. The tracing is monitored throughout the test.

3. A blood pressure cuff will be placed around your arm and a baseline pressure recorded. This will also be checked throughout the test as you walk.

4. Once you are comfortable and happy, the treadmill is started at a very slow pace. The treadmill is electric and you do not need to push it, simply walk in your normal stride. You will be required to walk slowly at a pace which is usually slower than most people walk in their every day activities.

5. After 3 minutes, and after checking the ECG tracing and blood pressure to make sure there are no changes, the speed and slope of the treadmill increase.

AT ANY STAGE THE TREADMILL WILL BE STOPPED AT YOUR REQUEST.

6. Depending on age and fitness, you may be on the treadmill for 2 to 15 minutes with most people doing about 6 to 10 minutes. The treadmill is stopped if there are any changes on your ECG tracing, if you have any symptoms, if you ask us to stop or if our target heart rate is reached.

Is an Exercise Test safe? Exercise testing is extremely safe and is non-invasive. Because you are being monitored so closely, it is arguably safer than your usual walk down the street during every day activities.

 What should I do to prepare for the test?

1.     No special preparation is needed.

2.     Wear comfortable clothing and shoes, although it is possible to do with almost any shoes or barefoot.

3.     It is advisable to wear a two piece outfit.

4.     No fasting is needed.

5.     Take all your usual medications, although if you take beta-blockers please discuss with us or you’re referring Doctor whether to continue these on the day of your test.