Thallium stress test is a kind of nuclear scanning test that is conducted to test the activity of the heart in a state of rest as well as during physical exercise. This is an imaging test that gives an accurate estimate of how big the chambers of the heart are and how well blood is being circulated into the muscles of the heart. Thallium Stress Test also helps detect blockages in the coronary arteries and helps monitor the response of the heart muscles to medication administered as part of treatment following a cardiac arrest or heart surgery. It is also useful in determining the risk of further complications and the course of treatment that should be followed to prevent the same.
The actual procedure that is followed during the test is fairly simple and completely painless. You would be required to walk on a treadmill. If you have a severe respiratory problem or suffer from acute pain in the joints and consequently cannot bear physical strain, your doctor may alternatively administer to you a kind of medicine called vasodilator, which makes your heart beat faster without your having to engage in physical exercise. Once you have reached a stage when your heart starts to beat rapidly, a medical assistant will inject a small portion of a radioactive substance (usually thallium) into one of your veins. Following this, you will be asked to lie down on a table and a camera will move over your chest to obtain images of your heart.
Another set of images will be obtained once your heartbeat is back to normal after a few hours of rest. Usually, the entire procedure takes about 4 hours. It is by comparing the two sets of images that your doctor assesses the functioning of your heart. If the circulation of blood in your heart muscles is found to increase normally under physical stress then your coronary arteries are supposed to be in good working condition. If, however, it is observed that the supply of blood to your heart is normal in a state of rest but inadequate when you are engaged in physical exercise, then it is inferred that your heart muscles are not getting enough blood supply under stress. This could be indicative of a narrowing of or obstruction in a coronary artery. The nuclear scan image reveals exactly which part of the heart receives blood insufficiently and thereby helps determine the necessary course of action.
Submitted by M T on February 14, 2010 at 10:39