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People with heart disease often show normal results on heart tests performed under resting or relaxed conditions. However, these test results can look abnormal when the heart is made to work harder, and since exercise is the most common way to stress a person's heart, this is the basis for exercise stress tests.

During an exercise stress test, your heart activity (ECG) and blood pressure readings are recorded while you walk on an exercise treadmill. The test helps determine the causes of chest pain or if a person without symptoms has silent coronary artery disease (i.e., blockages or hardening of the arteries of the heart). It can also help to identify heart rhythm disturbances during exercise and the capacity of the heart for exercise after cardiac surgery or a heart attack.

Technologists place ECG electrodes on your chest, which are connected to a special monitoring station. A blood pressure cuff is placed on one of your arms. Exercise begins slowly and the speed and grade of the treadmill increases gradually every three minutes. A specially trained, registered nurse monitors your heart's response to an increased workload and asks you to report any symptoms, such as chest pressure or arm pain. The test continues until you reach a target heart rate, unless complications such as chest pain develop. Monitoring continues 10 to 15 minutes after you finish exercising or until the heart rate returns to its baseline.

To increase the accuracy of the test, you must exercise as long as you can. The nurse will stop the treadmill when you tell the nurse that you have exercised to your maximum potential. When the exercise portion of your stress test is finished, there will be an appropriate recovery period, during which your ECG rhythm, blood pressure and any symptoms you have experienced will continue to be monitored.

The nuclear stress test is used to evaluate the supply of blood to your heart muscle. This stress test is performed in combination with the use of Cardiolite and Thallium, which are radioactive tracers. A normal heart shows uniform uptake of these radioactive substances. However, if there is a blockage in one or more of the coronary arteries, there will be a "spot" or "defect" on the image. The use of these radioactive tracers provides more accurate and detailed information than that provided by a regular treadmill test.

To begin the test, an intravenous line (IV) is inserted into your arm. You then receive a small dose of a radioactive tracer, Thallium, which does not cause any side effects. After this injection, you lie very still on a table, where a special camera rotates around your chest, taking pictures of your heart.

You then perform the exercise portion of your test as described above. Approximately one minute before you reach your peak exercise, a second radioactive tracer, Cardiolite, is injected. The nurse monitoring your test helps you determine when this occurs. Approximately 45 minutes after the injection of the second tracer, your "stress images" are taken.

An exercise stress test with echocardiography combines ultrasound and the treadmill test to give more accurate and detailed information than what is provided by a regular treadmill test. In addition to the ECG electrodes and blood pressure cuff described in the exercise stress test above, a sonographer takes a few ultrasound pictures while you are lying on a stretcher and enters these images into the computer. After the treadmill test, you then get back into position on the stretcher for the sonographer to take "after exercise" images. These images are compared to the original images taken prior to the exercise. Your heart rate and rhythm and blood pressure are monitored continuously.

For patients who are unable to exercise for any reason, intravenous (IV) medicines may be given in place of exercise to make the heart work as hard as if the person was running. This is called pharmacologic stress testing, and it is used to diagnose the same heart conditions revealed by an exercise stress test, including "silent" coronary artery disease (i.e., blockages or hardening of the arteries of the heart). It can also help to identify heart rhythm disturbances during exercise and the capacity of the heart for exercise after cardiac surgery or a heart attack.

Dobutamine is similar to a chemical that your own body releases when it needs to increase its activity. The drug increases your heart rate and the strength of your heart muscle contraction. During the test, an IV is inserted into your arm to infuse the Dobutamine. The Dobutamine medication is given to you slowly in several stages over a 15 minute period. A registered nurse performs this procedure under the direction of a cardiologist. Your heart activity (ECG) and blood pressure readings are recorded continuously during the test. A sonographer also takes ultrasound images of your heart before the test begins and at several different stages during the exam. More images of your heart are recorded after the drug is stopped. Your heart action returns to normal within a few minutes. If you experience any symptoms, such as chest or arm pain, shortness of breath or lightheadedness, you should immediately inform the nurse or physician supervising your test. The stress test is followed by a five- to ten-minute recovery period, during which your heart rate, rhythm and blood pressure are monitored until they have returned to baseline.