Department of CARDIOLOGY
Dr. Yadvinder Singh
- Stress Echo/TMT
Cardiology is the study and treatment of disorders of the heart; it is a medical specialty which is involved in the care of all things associated with the heart and the arteries. A cardiologist is not the same as a cardiac surgeon – the cardiac surgeon opens the chest and performs heart surgery, a cardiologist, on the other hand, carries out tests and procedures, such as angioplasty.
Heart disease differs from cardiovascular disease, in that the latter refers to disorders and illnesses of the heart and blood vessels, while the former is only concerned with the heart.
Interventional Cardiology – involves the use of intravascular catheter-based techniques with fluoroscopy to treat congenital cardiac, valvular and coronary artery diseases. Interventional cardiologists may perform angioplasties, valvuloplasties, congenital heart defect corrections, and coronary thrombectomies.
Echocardiography – the use of ultrasound waves to create images of the heart chambers, valves and surrounding structures. Echocardiography can measure how well the heart is pumping blood (cardiac output), as well as determining levels ofinflammation around the heart (pericarditis). Echocardiography can also be used to identify structural abnormalities or infections of the heart valves.
Cardiac electrophysiology – the study of the mechanism, spread, and interpretation of the electric currents which occur inside heart muscle tissue – the system that generates the heart beat.During an electrophysiology study (EPS) of the heart, catheters are threaded into a vein at the top of the leg; guided under fluoroscopy, the catheter makes its way to the heart. The catheters measure the electrical signals within the heart. EPS of the heart may be performed to determine whether the patient
needs a pacemaker, why somebody is fainting if other tests have found no cause, and to help decide the best treatment for patients with arrhythmia (abnormal heart rhythm). EPS may also determine how prone a patient is to tachycardia (accelerated heart beat).
TMT or Stress Test It is common to find heart patients who have normal ECG. One must remember that the ECGs are taken at rest when the heart is beating at its lowest rate. Even with 90% blocks the patients can have a normal ECG. In such cases the patient would also agree that at rest there is no pain in the chest, the angina symptoms would only come when they increase the heart rate, while doing some physical exertion like walking. This is the condition where we need a TMT test. The patients are to gradually increase their heart rate, thus increasing the blood requirement of the heart muscles. Simultaneously ECG records are taken. If there is a blockage of approximately more than 70% ECG shows changes, suggestive of Angina.
Patients have to physically exert for this test which uses a computerised machine. The level of the exercise is gradually increased according to a standard protocol called the Bruce’s Protocol. The continuous ECG monitoring during the exercise would reflect any blood and oxygen deficit in the muscles of the heart during exercise.
The Patient is asked to stop exercising as soon as ECG changes appear or any symptoms of chest pain or discomfort or breathlessness are felt.
TMT test is also called Exercise Stress Test, Computerised Stress Test or simply Stress test. This is the most easy, popular and common test performed on heart patients to determine the severity of the heart disease. Taken at an interval, this test can also show the improvement or deterioration of patient’s angina.
A negative TMT or Stress Test is declared when the patient can reach a certain heart rate without showing any ECG changes. This rate is called a target heart rate and is calculated by a formula (Target Heart Rate = 220 – age of patient). If this rate is reached by the patient without producing any ECG changes, though the TMT can be called negative, but it would not mean that the blockage is zero. It will only mean that the person performing the test probably has a blockage less than 70%