Electrocardiogram (EKG or ECG)

An electrocardiogram, sometimes called an EKG or ECG, is a common, noninvasive test to help diagnose a problem with your heart or tell your doctor if you’ve had a heart attack, heart failure or heart damage. It can also tell them if your heart rate or rhythm isn’t normal or how well your pacemaker is working.

An electrocardiogram (EKG) test records electrical activity in the heart. It can be done in your doctor’s office, a clinic or hospital. Some personal devices, such as smartwatches, also feature electrocardiogram (EKG) monitoring.

EKG and ECG tests are both abbreviations for an electrocardiogram, so there is no difference between the two tests. ECG stands for "electrocardiogram" in English, while EKG is based on the German spelling "elektrokardiogramm."

What is an EKG test?

An EKG test checks your heart’s electrical activity through electrodes attached to your chest, arms and legs. The electrodes send information to a computer, and the results are recorded as digital files.

What does an EKG test tell you?

The potential benefit of an EKG test is to prevent cardiovascular events such as heart attacks, strokes and death. Most of this benefit occurs in people at high risk of cardiovascular disease. Your doctor may use an EKG test to screen for:

Genetic heart problems, particularly if a parent or sibling had heart disease, especially early in life
Heart health before surgery
Heart problems in their early stages before you even notice symptoms
Your heart’s reaction to a new medication

An electrocardiogram (EKG) test can also help your doctor diagnose many common heart problems, including:

Are you at risk for heart disease?

Knowing your risk factors of heart disease – the leading cause of death in the U.S. – can help you lower your chances of developing it. Our heart health quiz estimates your risk, determines which of your risk factors are controllable and gives you an idea of what to do next based on your results.

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Symptoms that may require an EKG

Your doctor might order an electrocardiogram (EKG) test if you have any of the following signs and symptoms:

Chest pain
Dizziness, lightheadedness or confusion
Heart palpitations
Rapid pulse
Shortness of breath
Weakness, fatigue or a decline in your ability to exercise

Other reasons you may need an electrocardiogram (EKG) test

Your doctor might also use an EKG test to detect:

How well your pacemaker or other cardiac device or treatment is working
If blocked or narrowed arteries in the heart (coronary artery disease) are causing chest pain or a heart attack
Irregular heart rate or rhythm (arrhythmia)
Whether you've had a previous heart attack

Remote EKG test for intermittent symptoms

If your symptoms don’t happen all the time, they may not be detected during a standard EKG test. If this is the case, your doctor might recommend remote or continuous EKG monitoring such as:

Holter monitor: A Holter monitor is a small, wearable device that records a continuous electrocardiogram (EKG), usually for 24 to 48 hours.
Event monitor: This portable device is similar to a Holter monitor, but it records only at certain times for a few minutes at a time. You can wear it longer than a Holter monitor – typically 30 days. You generally push a button when you feel symptoms. Some devices automatically record when an irregular rhythm is detected.

How to prepare for an EKG test

When getting ready for your electrocardiogram (EKG) test:

Avoid oily or greasy skin creams and lotions because they can keep the electrodes from making contact with your skin.
Avoid full-length socks or tights because electrodes need to be placed directly on your legs.
Wear a shirt you can remove easily to place the electrodes on your chest.

What to expect during an EKG test

The EKG is a very simple test that doesn’t require any special preparation on your part.

The resting 12-lead electrocardiogram – the standard EKG test – takes about 15 minutes. During the EKG test, you’ll change into a hospital gown and lie on your back. The technician will place 12 EKG lead wires to adhesive electrodes on your chest, legs and arms. You’ll need to lie very still for about 10 minutes while the EKG is recorded.

After the test, you’ll be able to go home the same day with no restrictions in your activities. A physician who specializes in reading EKGs will review your test results and send them to your doctor.