This test is for those who have symptoms of heart disease even when their ECG recording is normal. So the underlying heart disease remains to be accurately diagnosed. Thus, TMT is done when there is doubt of possible heart disease despite a near-normal ECG.
The test is done while you walk or run on a treadmill (an endlessly moving belt). Your ECG is continuously recorded while you keep walking. If you have a narrowed coronary artery i.e. less blood flows through it. It is recorded on the ECG and a diagnosis can be made. In case you have chest pain or discomfort while the test is on, it is instantly stopped. Your blood pressure and ECG are recorded before a TMT.
In the beginning, the endless belt moves slowly so you may walk at a slow pace. Gradually, the speed of the belt increases. It also inclines upwards so that you have to walk up a slope. You have also to walk rapidly in an upwardly inclined position. Gradually, the heart is exerted more and more and it beats faster and faster. This activity is recorded on the ECG.
In the meanwhile, your BP is checked at intervals.
Your heart rate and blood pressure begin to increase, if you have angina. It will be detected on the ECG taken, while you walk rapidly up the slope.
In case you get chest pain, the test is instantly stopped. An experienced doctor is always there, ready to give emergency medical treatment if it is a required. Emergency medical drugs and equipment are always ready in a TMT lab.
TMT is a reasonably safe and non-invasive test to determine cardiac function. It is useful in patients with symptoms of angina, but with a normal ECG.
If, however, you are unable to walk, you cannot undergo TMT. If you are obese have knee pain, are short of breath, or have very high BP, have valvular heart disease etc., TMT can not be done.
For such patients, Dobutamine Stress Echocardiography or Thallium Testing is done.
TMT may be used as a routine two yearly test after the age of 40 to monitor the performance of the heart under the stress of exercise.