Quick Search

Stress tests are usually performed while exercising, and the results help determine causes of chest pain or the presence of silent coronary artery disease. It can also identify heart rhythm disturbances and the capacity for exercise after cardiac surgery or heart attack.

During the test, heart activity (ECG) and blood pressure readings are recorded while you walk on a treadmill.

Exercise begins slowly and the speed and grade of the treadmill increases gradually every three minutes. The heart's response to the increased workload is monitored and any symptoms, such as chest pressure or arm pain are noted. The test continues until a target heart rate is reached, unless complications develop and it is stopped. Monitoring continues after exercise stops until the heart rate returns to its baseline.

Ultrasound images and the treadmill test are combined when more accurate and detailed information is needed. Images are taken before and after exercise. Heart rate, heart rhythm and blood pressure are monitored continuously and the before and after images are compared.

The dual isotope stress test evaluates blood supply to the heart muscle and is done using the radioactive tracers Cardiolite and Thallium. In a normal heart, uptake of these substances is uniform. If there is a blockage in one or more coronary arteries, a spot or defect appears on the image.

An IV in your arm delivers a small dose of the radioactive tracer Thallium. After the injection, a special camera rotates around your chest taking pictures of your heart while you lie still. Approximately one minute before peak exercise, a second radioactive tracer, Cardiolite, is injected and 45 minutes later stress images are taken.

For patients unable to exercise, intravenous (IV) medicines may be used to make the heart work as hard as if the person were running. This is called pharmacologic stress testing and is used to diagnose the same heart conditions revealed by an exercise stress test.

Dobutamine is similar to a chemical that your body releases when it needs to increase activity. It increases heart rate and the strength of heart muscle contraction. Dobutamine is infused through an IV in your arm in several stages over 15 minutes. Heart activity (ECG) and blood pressure readings are recorded continuously during the test. Ultrasound images of your heart are taken before the test, at several different stages, and after the drug is stopped. When finished, the recovery period is five to ten minutes and heart rate, rhythm and blood pressure are monitored until they have returned to baseline.