What To Expect During Stress Testing

During all types of stress testing, a technician or nurse will always be with you to closely check your health status.

Before you start the "stress" part of a stress test, the technician or 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 technician or nurse may have to shave a patch of hair where the electrode will be attached.

The electrodes are connected to an EKG (electrocardiogram) machine. This machine records your heart's electrical activity and 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 each part of your heart.

The technician or 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 may be asked to breathe into a special tube so the gases you breathe out can be measured.

After these preparations, you'll exercise on a treadmill or stationary bicycle. If such exercise poses a problem for you, you may instead turn a crank with your arms. During the test, the exercise level will get harder. You can stop whenever you feel the exercise is too much for you.

Stress Testing

The illustration shows a patient having a stress test. Electrodes are attached to the patient's chest and connected to an EKG (electrocardiogram) machine. The EKG records the heart's electrical activity. A blood pressure cuff is used to record the patient's blood pressure while he walks on a treadmill.

If you can't exercise, medicine may be injected into a vein in your arm or hand. This medicine will increase blood flow through your coronary arteries and/or make your heart beat fast, as would exercise. The stress test can then be done.

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 technician will frequently 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 abnormal heartbeat)
• Become dizzy

The technician will continue to check your heart functions and blood pressure after the test until they return to your normal levels.

The "stress" part of a stress test (when you're exercising or given medicine that makes your heart work 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 technician 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 usually can't hear. The echoes from the sound waves are converted into moving pictures of your heart on a screen.

You may be asked to lie on your side on an exam table for this test. Some stress echo tests also use a dye to improve imaging. This 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 tests that use radioactive dye, the technician will inject a small amount of dye (such as sestamibi) into your bloodstream. This is done through a needle placed in a vein in your arm or hand.

You're usually given 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 thought to be safe and not a danger to you or 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 see 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.