A stress test is used to make sure the heart muscles are able to get enough blood when the heart rate and workload are increased. To do this, your heart needs to be looked at during a period of rest and then again during a period of increased activity. A chemical stress test uses chemical agents injected into the body through the vein. These chemicals make the heart function as if it were under stress.
There are many different ways to examine the heart during a stress test. The heart can be examined with:
A chemical stress test is used when a
traditional stress test
(called a cardiac stress test) cannot be done. A cardiac stress test requires you to walk on a treadmill or ride a stationary bicycle until your heart rate reaches a level where your heart is stressed. You may not be able to participate in this test if you have certain conditions such as:
You will lie down on a table. A technician will place electrodes on your chest. Your resting blood pressure and ECG readings will be taken. An IV will be placed in your arm. You will be hooked up to a heart monitor that will record your heart’s activity. Your blood pressure and heart rate will be checked often. A small amount of chemical will be injected through the IV and into your body. Depending on which chemical is used, your heart will beat faster and/or the blood vessels near your heart will open wider. An ECG may also be done at this time.
If you have chest pain, trouble breathing, lightheadedness, or any other symptoms, report them right away. The test may need to be stopped. Changes in the ECG may also be a reason to stop the test.
If you are getting nuclear imaging, the technician will inject a mildly radioactive chemical through your IV. Thirty to sixty minutes after the chemical injection, a special camera or an MRI will be used to track the flow of the chemical through and around your heart. Images will be taken to find areas of the heart that may not be getting enough blood or are blocked. If you are getting a stress echocardiogram, an ultrasound will be taken at specific time points. The pictures of your heart under stress will be compared with pictures of your heart at rest.
Your blood pressure, heart rate, and ECG will be monitored until levels return to normal. You will be able to leave after the test is done.
How Long Will It Take?
Typically takes 3-4 hours to complete (may be done over 1-2 days)
Will It Hurt?
You should not feel pain during the test. You may feel a pinch when the IV is inserted. You may also feel a flushing sensation when the medication is injected.
Your doctor may discuss some of the results on the same day as the test. It may take 2-3 days for the full results to be ready.
One or more of the following are considered a positive stress test:
ECG changes that show low oxygen supply to the heart
Significant blood pressure drops or rhythm changes
You have chest pain or trouble breathing, especially if linked with ECG changes
Stress test pictures that show areas of your heart having low blood flow or abnormal movements
A positive test may mean that you have CAD. Not everyone tests positive for it. Based on your results, your doctor may recommend more tests or care.
Pearson TA, Blair SN, Daniels SR, et al. AHA guidelines for primary prevention of cardiovascular disease and stroke: 2002 update. Circulation. 2002;106(3):388-391.
Stress testing. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/cardiovascular-disorders/cardiovascular-tests-and-procedures/stress-testing. Updated September 2017. Accessed February 28, 2018.
Stress testing. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health-topics/stress-testing. Accessed February 28, 2018.
What is a stress test? American Heart Association website. Available at: https://www.heart.org/idc/groups/heart-public/@wcm/@hcm/documents/downloadable/ucm_300453.pdf. Accessed February 28, 2018.
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