A treadmill test, also called a TMT (or TMT test), is a test that is performed to diagnose patients who may be suffering from a suspected heart disease. It is also called an exercise stress test.
Why Is A Treadmill Test Done?
A treadmill test is useful for many reasons. It can determine if the blood supply to the heart is reduced.
It can also help determine if the patient’s lungs are in a good condition. It can help in determining exercise tolerance as well.
Treadmill tests are performed according to guidelines that have been laid down by the American Heart Association.
Preparing For A Treadmill Test
If you are taking medicines for blood pressure or diabetes, you doctor will advise you as to whether you should take these on the day of the test.
The treadmill test is best done on an empty stomach. This is because the exercise can sometimes make you nauseous, especially if you have had some food a short while ago.
Men will need to shave their chest till their naval. Women should wear comfortable clothing – if possible trousers and a T-shirt. Bring some comfortable shoes with you.
How Is A Treadmill Test Performed?
An exercise treadmill test is performed as an outpatient test. It involves a patient having to walk on a treadmill while being attached to an ECG monitor that records the heartbeat throughout the test.
The patient arrives at the diagnostic center ideally on an empty stomach. It is recommended that the patient wear comfortable walking shoes so that they do not experience any inconvenience or difficulty walking on the treadmill.
A full consent will be taken and the patient is then attached to the monitor using a series of ECG leads on the chest wall. Female patients will be offered a gown during the test.
Please note: In order to place the ECG leads on the chest, the patient’s chest will need to be exposed. Men will need to have their chest shaved so that the leads can be attached firmly to the skin of the chest. Women will need to remove their undergarments so that leads can be attached to their chest wall. Following this, women will be covered in a gown.
Once the patient is attached to the monitor, they will be asked to lie down and a blood pressure recording will be taken. The patient will then be asked to stand up and another BP recording will be taken.
If the blood pressure is too high, it is unsafe to do the test, and it may be rescheduled for another day.
Following this, a technician or the doctor will demonstrate how to walk on the treadmill. Once the patient feels comfortable they will be asked to stand on the treadmill.
The treadmill is then turned on and the patient is asked to walk at a steady pace keeping their back straight while looking straight ahead. While this may be slightly difficult initially, there is nothing to worry about as the technician or the doctor will offer the guidance and support that is required to make sure that the patient is comfortable.
The treadmill moves at a slow speed to start off with and has a slight incline (depending on the type of test). It feels as if one is walking up a hill. Every 3 minutes, the doctor will check the patient’s blood pressure and record it.
At the same time, the treadmill will increase in speed and incline slightly. The heart rate will be constantly monitored along with the blood pressure.
In short, the treadmill test consists of stages, each of which last 3 minutes. With each advancing stage, the test becomes slightly harder.
If at any point the patient develops any chest pain or is unable to walk comfortably on the treadmill, the test will be stopped either at the physician’s request or at the patient’s request.
Another BP recording will be taken and the patient will be asked to relax for a few minutes before the test is concluded.
The entire test can take anywhere between 30 to 45 minutes to perform. This depends completely on the exercise capacity of the patient and also on the information that is obtained during the test.
After the test has concluded, the ECG leads will be taken off and the patient will be asked to dress themselves.
The report is provided immediately after the test. Recommendations for further investigations may be offered as well depending on the results.
What Information Does A Treadmill Test Provide?
An exercise treadmill test offers information regarding whether or not the heart is able to undergo increasing amount of stress during exercise.
The basic principle underlying a treadmill test is simple. During exercise, the heart beats faster and needs more blood to function.
If there is underlying narrowing of the heart arteries which is reducing the amount of blood reaching the heart, then during the exercise test, there will be changes on the heart monitor that will demonstrate this.
In other words, changes in the ECG are reflective of changes in blood flow to the heart.
Patients may experience chest pain along with these changes. This is usually indicative of underlying heart artery disease.
In addition to this, the exercise stress test also provides information regarding the exercise capacity of patients and can sometimes be performed for patients with heart failure. It is also performed for patients who have undergone previous coronary artery bypass grafts or coronary intervention of any sort.
Types Of Exercise Treadmill Tests
While there are a number of different types of exercise stress test protocols, there are broadly two different kinds – Bruce protocol and modified Bruce protocol.
The difference between the two is the stress the patient undergoes during the test.
The Bruce protocol is performed on patients who are healthier and can withstand a greater degree of stress on the treadmill.
The modified Bruce protocol is offered to patients who have underlying heart disease and who may not be able to tolerate the Bruce protocol.
The decision as to which protocol is best suited for the patient will be made by the physician.
The information obtained from an exercise stress test may sometimes be inconclusive as the patient may not be able to walk easily on the treadmill.
In addition, there may be certain changes seen on the ECG that are not particularly indicative of underlying coronary artery disease.
A treadmill test will not be performed in certain patients who suffer from narrowed heart valves, a very recent heart attack and severe heart failure.
If the patient’s blood pressure is very high at the start of the test, the exercise stress test may be postponed.
Risks Of A Treadmill Test
An exercise stress test is performed under close supervision by a physician.
While the risks of any sort are rare, it is good to be aware that in patients who have significant underlying coronary artery disease that has not yet been diagnosed, an exercise stress test can induce chest pain and sometimes even cause a heart attack. Some patients may also experience an irregular heartbeat. These are risks are extremely rare.
A treadmill test is a useful test to find out why you are getting chest pain. It can help determine if the flow of blood to the heart is reduced.
For more on how to diagnose heart blockages, click here.