Do I Need a Stress Test?
Dr. Francesca Delling, a cardiologist at Beth Israel Deaconess Medical Center
Q. What is a stress test used for?
A. In a patient with chest pain of unknown cause, a
stress test is used to make a diagnosis of
coronary artery disease (blockages in the coronaries, the vessels that supply the heart muscle with blood).
In a patient with known coronary artery disease or a prior
heart attack, a stress test is used to predict future heart attacks or risk of death.
The patients at greater risk, based on the results of the stress test, are the ones that benefit the most from a
cardiac catheterization and possible
stent placement or
Q. How do I know if I need a stress test?
A. Patients who experience chest discomfort that occurs with exertion and is relieved by rest, particularly in patients with risk factors for coronary artery disease (such as
high cholesterol levels,
hypertension or family history of heart attacks at a young age), should be evaluated with a stress test.
Q. What happens during the test?
A. There are two types of stress test: exercise based or pharmacologic.
During an exercise tolerance test (ETT), the patient is asked to walk on a treadmill or, more rarely, to ride a bike, and an
electrocardiogram is recorded during exercise. Any symptoms or changes on the electrocardiogram are monitored.
An exercise test can be performed by itself or in combination with an
echocardiogram (ultrasound) or pictures obtained after the injection of a radioactive tracer that binds to any part of the heart muscle that is deprived of blood flow because of coronary blockages. If a patient is unable to exercise, a medication is given that mimics exercise either by increasing the heart rate and "squeeze" (dobutamine) or by causing relaxation of the coronary arteries.
Q. What will the test tell the doctor about my heart?
A. It will tell if there are any areas of the heart muscle that suffer from low blood supply secondary to blockages in the coronary arteries.
Q. Can it determine if my arteries are clogged or predict whether I may be at risk for a heart attack?
A. Although it can't show the blockages in the coronary arteries (only a more invasive test such as a
cardiac catheterization can do this), it can determine the effect of these blockages by showing abnormalities on the electrocardiogram (on a plain exercise test) or by showing the areas that suffer from low blood supply (on a stress test with imaging).
In a patient that is known to have coronary blockages because of a previous heart attack, a stress test gives information about the risk of having another heart attack or dying from one. We can tell this by observing how well one can exercise before having chest pain, or by looking at the size of the heart muscle area that is suffering from poor blood supply (seen on the ultrasound or on images obtained after injection of a radioactive tracer).
Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
Posted September 2010