Test assesses how well the heart responds to exercise ‘stress’
A cardiac stress test or treadmill test is done to measure how well your heart performs during exercise. During the test you will walk on a treadmill while your blood pressure, heart rate and breathing are monitored. You will also be hooked up to an electrocardiography (ECG) machine to monitor the electrical activity of your heart. In some patients, a special medication is used instead of the treadmill. The medication makes your heart respond the same way it would during exercise. Sometimes images of your heart are taken during the test (stress echocardiogram or stress echo). Some cardiac stress tests also involve injection of contrast dye through an intravenous (IV) line. The contrast dye reaches the heart and makes for clearer images of the heart and its performance.
You may need a cardiac stress test if your doctor suspects coronary artery disease (CAD). It may also be used to determine the cause of symptoms such as chest pain or shortness of breath. A stress test can also help predict future risk of heart attack.
The term cardiac stress test is also used interchangeably with nuclear stress test, myocardial perfusion SPECT (single proton emission computed tomography), cardiac SPECT, and stress perfusion test.
How a cardiac stress test is done
You will be asked to wear comfortable clothing and shoes. You may also be asked to avoid any caffeinated drinks for a day or so before your test. Drinking caffeine affects your heart rate and may produce an inaccurate reading. If you are having a treadmill test, you will have electrodes (small patches) attached to areas of your body. The person administering the test may shave those areas before attaching the electrodes. You will be asked to walk on the treadmill and then to walk at an accelerated pace. The ECG machine will monitor your heart to see how it responds to the “stress” of increased physical exertion.
If you are having a pharmacological stress test (medication-induced stress) you’ll receive the medication and you’ll be monitored in the same way, to see how your heart rate and blood pressure are affected by the stress.
The test usually takes about 60 minutes. Afterwards you may resume normal activities. If you had a radioactive tracer injected for an imaging cardiac stress test, you’ll need to drink plenty of fluids to flush the tracer out of your body.
Your doctor will review the results of the cardiac stress test with you and make any additional testing or treatment recommendations.