Exercise Electrocardiogram (EKG)

Test Overview

An exercise electrocardiogram (EKG or ECG) is a test that checks for changes in your heart while you exercise. Sometimes EKG abnormalities can be seen only during exercise or while you have symptoms. This test is sometimes called a "stress test" or a "treadmill test." During an exercise EKG, you may either walk on a motor-driven treadmill or pedal a stationary bicycle.

The heart is a muscular pump made up of four chambers. The two upper chambers are called atria, and the two lower chambers are called ventricles. A natural electrical system causes the heart muscle to contract and pump blood through the heart to the lungs and the rest of the body.

An exercise EKG translates the heart's electrical activity into line tracings on paper. The spikes and dips in the line tracings are called waves.

A resting EKG is always done before an exercise EKG test. Then results of the resting EKG are compared to the results of the exercise EKG. A resting EKG may also show a heart problem that would make an exercise EKG unsafe.

Why It Is Done

An exercise electrocardiogram is done to:

• Help find the cause of unexplained chest pain or pressure.
• Help decide on the best treatment for a person with angina.
• See how well people who have had a heart attack or heart surgery are able to tolerate exercise.
• Help find the cause of symptoms that occur during exercise or activity, such as dizziness; fainting; or rapid, irregular heartbeats (palpitations).
• Check for a blockage or narrowing of an artery after a medical procedure, such as angioplasty or coronary artery bypass surgery, especially if the person has chest pain or other symptoms.
• See how well medicine or other treatment for angina or an irregular heartbeat is working.
• Help you make decisions about starting an exercise program if you have been inactive for a number of years and have an increased chance of having heart disease.

How To Prepare

• Your doctor may recommend how you should eat before the test. For example, your doctor may suggest you only eat a light breakfast before your test.
• If you smoke, your doctor may recommend that you do not smoke for about 4 hours before the test.
• Remove all jewelry from your neck, arms, and wrists. Wear flat, comfortable shoes (no bedroom slippers) and loose, lightweight shorts or sweat pants. Men are usually bare-chested during the test. Women often wear a bra, T-shirt, or hospital gown. Avoid wearing any restrictive clothing other than a bra.
• You may want to stretch your arm and leg muscles before you start an exercise EKG.
• Understand exactly what test is planned, along with the risks, benefits, and other options.
• Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.

How It Is Done

You most likely will either walk on a treadmill or pedal a stationary bicycle.

You will have a blood pressure cuff on your upper arm. Small pads or patches (electrodes) will be placed, like stickers, on your skin on each arm and leg and on your chest. Your doctor may wrap your chest with an elastic band to keep the electrodes from falling off.

On the treadmill, you will start out slowly in a level or slightly inclined position. After certain periods of time, the speed and steepness of the treadmill will be increased so that you will be walking faster and at a greater incline.

On the stationary bicycle, you will pedal fast enough to keep a certain speed. After certain periods of time, the resistance will be increased, making it harder to pedal.

In both tests:

• Your EKG, heart rate, and blood pressure are recorded.
• You might be asked to use numbers to say how hard you are exercising. The higher the number, the harder you think you are exercising.
• The test will continue until:
  • You need to stop.
  • You have reached a target heart rate.
  • You have angina symptoms, such as chest pain or pressure.
  • You are very tired or very short of breath.
  • Your doctor feels you need to stop because of a change in your heartbeat or blood pressure.

After the test, you will be able to sit or lie down and rest. Your EKG and blood pressure will be checked for about 5 to 10 minutes.

How long the test takes

The test may take about 30 to 60 minutes.

How It Feels

The electrodes may feel cool when they are put on your chest. If you have a lot of hair on your chest, a small area under each electrode may need to be shaved. When the electrodes are taken off, they may pull your skin a little.

The room where the exercise electrocardiogram is done may be kept cool for comfort, since you will warm up rapidly when you begin to exercise.

The blood pressure cuff on your arm will be inflated every few minutes. This will squeeze your arm and feel tight. Tell your health professional if this is painful.

While you exercise, you may have leg cramps or soreness; feel tired, short of breath, or lightheaded; have a dry mouth; and sweat. You might even have some mild chest pain or pressure. Tell the health professional or doctor if you have these symptoms.

Risks

• There is very little chance of having a problem from this test.
• Risks include:
  • Irregular heartbeats during the test.
  • Severe angina symptoms.
  • Fainting.
  • Falling.
  • Heart attack.
• No electricity passes through your body during the test. There is no danger of getting an electrical shock.

Results

Your doctor may be able to talk to you about your results right after the test. But complete test results may take several days.

Your doctor will look at the pattern of spikes and dips on your EKG to check the electrical activity in different parts of your heart. The spikes and dips are grouped into different sections that show how your heart is working.

Some people who have a normal exercise EKG may still have heart disease. And some people with an abnormal test don't have heart disease.