Your doctor may recommend that you undergo a cardiac stress test if you are having symptoms that may indicate underlying heart problems. This test is used to measure your heart's ability to respond to external stress in a controlled clinical environment. Your doctor may order an exercise stress test if you are able to walk and perform exercise. If you are unable to do that, your doctor may order a
pharmacological stress test.
A stress test is used to evaluate the heart and vascular system during exercise and can help answer two questions: 1) Is
coronary artery disease (CAD) present and apparent when the heart is stressed? 2) If there is underlying heart disease, how severe is it likely to be?
What happens during the test? During the test, you will walk on a treadmill while connected to an
electrocardiogram (ECG). The ECG will be attached to your chest with leads (wires) and a blood pressure cuff will be placed on your arm. A sensor may be placed on your finger to measure the amount of oxygen in your blood. After a baseline ECG is obtained, you will be asked to begin performing a low level of exercise either on a treadmill or a stationary bike. The level of mechanical stress is progressively increased by adjusting the difficulty and speed. The test administrator examines your symptoms and blood pressure with each increase.
After the test, you will be monitored until any symptoms disappear and until your pulse, blood pressure and ECG return to their baseline levels.
What can the test results show? Your physician will use the results from your stress test to diagnose whether coronary artery disease (CAD) is producing blockages in the coronary arteries, which supply blood to the heart muscle. If a partial blockage is present, the heart muscle may still get all the blood supply it needs in the resting state, but not while under stress (during exercise). By "stressing" the heart with exercise, the stress test can bring out abnormalities caused by partial blockages in the coronary arteries - abnormalities that are often completely unapparent at rest.
Because exercise raises adrenaline levels, stress tests can also be useful in diagnosing certain cardiac
arrhythmias that tend to occur at times when adrenaline levels are increased. Stress tests are also useful in measuring the "functional capacity" of patients with heart disease, by assessing the significance of partial blockages.
Who is a candidate for a stress test? The American Heart Association recommends exercise treadmill testing for patients with medium risk of coronary heart disease, determined by risk factors such as smoking, family history, high blood pressure, diabetes and high cholesterol.
A cardiac stress test would be ordered by your physician to help diagnose any underlying cardiac conditions.
