During all types of stress testing, a doctor, nurse, or technician will always be with you to closely check your health status.
Before you start the "stress" part of a stress test, the nurse will put sticky patches called electrodes on the skin of your chest, arms, and legs. To help an electrode stick to the skin, the nurse may have to shave a patch of hair where the electrode will be attached.
The electrodes will be connected to an EKG (electrocardiogram) machine. This machine records your heart's electrical activity. It shows how fast your heart is beating and the heart's rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through your heart.
The nurse will put a blood pressure cuff on your arm to check your blood pressure during the stress test. (The cuff will feel tight on your arm when it expands every few minutes.) Also, you might have to breathe into a special tube so the gases you breathe out can be measured.
Next, you'll exercise on a treadmill or stationary bike. If such exercise poses a problem for you, you might turn a crank with your arms instead. During the test, the exercise level will get harder. You can stop whenever you feel the exercise is too much for you.
If you can't exercise, medicine might be injected into a vein in your arm or hand. The medicine will increase blood flow through your coronary arteries and make your heart beat fast, as it would during exercise. You can then have the stress test.
The medicine may make you flushed and anxious, but the effects go away as soon as the test is over. The medicine also may give you a headache.
While you're exercising or getting medicine to make your heart work harder, the nurse will ask you how you're feeling. You should tell him or her if you feel chest pain, short of breath, or dizzy.
The exercise or medicine infusion will continue until you reach a target heart rate, or until you:
- Feel moderate to severe chest pain
- Get too out of breath to continue
- Develop abnormally high or low blood pressure or an arrhythmia (an irregular heartbeat)
- Become dizzy
The nurse will continue to check your heart functions and blood pressure after the test until they return to normal levels.
The "stress" part of a stress test (when your heart is working hard) usually lasts about 15 minutes or less.
However, there's prep time before the test and monitoring time afterward. Both extend the total test time to about an hour for a standard stress test, and up to 3 hours or more for some imaging stress tests.
Exercise Stress Echocardiogram Test
For an exercise stress echocardiogram (echo) test, the nurse will take pictures of your heart using echocardiography before you exercise and as soon as you finish.
A sonographer (a person who specializes in using ultrasound techniques) will apply gel to your chest. Then, he or she will briefly put a transducer (a wand-like device) against your chest and move it around.
The transducer sends and receives high-pitched sounds that you probably won’t hear. The echoes from the sound waves are converted into moving pictures of your heart on a screen.
You might be asked to lie on your side on an exam table for this test. Some stress echo tests also use dye to improve imaging. The dye is injected into your bloodstream while the test occurs.
Sestamibi or Other Imaging Stress Tests Involving Radioactive Dye
For a sestamibi stress test or other imaging stress test that uses radioactive dye, the nurse will inject a small amount of dye into your bloodstream. This is done through a needle placed in a vein in your arm or hand.
You’ll get the dye about a half-hour before you start exercising or take medicine to make your heart work hard. The amount of radiation in the dye is considered safe for you and those around you. However, if you're pregnant, you shouldn't have this test because of risks it might pose to your unborn child.
Pictures will be taken of your heart at least two times: when it's at rest and when it's working its hardest. You'll lie down on a table, and a special camera or scanner that can detect the dye in your bloodstream will take pictures of your heart.
Some pictures may not be taken until you lie quietly for a few hours after the stress test. Some patients may even be asked to return in a day or so for more pictures.