Electrocardiogram (EKG/ECG)

An electrocardiogram (EKG or ECG) is a quick, noninvasive test that records your heart’s electrical activity. Healthcare providers use it for many reasons, such as to diagnose heart rhythm issues or to monitor how well a treatment is working. You may get an EKG in your provider’s office, at a hospital or even in an ambulance, depending on why you need one.

A typical EKG must be done in a medical facility and only tracks your heart’s electrical activity for a short time. This is sometimes called a standard 12-lead EKG. You may get it while lying down and resting or while you’re exercising as part of a stress test.

But some heart rhythm problems only happen once in a while. That means a standard EKG may not show them. It’s like when your internet is acting up, but it seems fine when someone comes to repair it. So, in some cases, your healthcare provider may recommend a device that records your heart’s electrical activity for a longer time, like a Holter monitor or implantable loop recorder.

Why is an EKG done?

Healthcare providers use EKGs to:

• Find the cause of symptoms
• Diagnose heart conditions
• See how your heart is doing since you got a pacemaker
• See how well a new medication is working
• Make sure you’re fit for an upcoming surgery
• Evaluate your heart health if you’re at a higher risk for heart disease
• Check your heart rhythm after a heart attack

Your provider may give you an EKG if you have these symptoms:

• Chest pain
• Shortness of breath
• Tiredness
• Dizziness
• Fainting (syncope)
• Blue hands and feet (cyanosis)
• A flutter or skip in your heartbeat
• A fast heartbeat
• Difficulty with blood supply during physical activity (chronotropic incompetence)

How do I prepare for the test?

Before an electrocardiogram, you can eat and drink as you normally would. But on the day of your EKG test, try to:

• Avoid using oily or greasy skin creams and lotions. These keep the electrodes from making good contact with your skin.
• Avoid full-length pantyhose or tights that prevent the electrodes from touching the skin on your legs.
• Wear a shirt that you can remove easily when your provider places the leads on your chest.

What happens during an EKG?

A healthcare provider will attach 12 electrodes with adhesive pads to the skin on your chest, arms and legs. They’ll put six electrodes (sensors) on your chest and six on your limbs. To allow a better connection, your provider may shave any hair that’s in the way. The sensors send information through wires or leads, which is why people call it a 12-lead EKG.

For a resting EKG, you’ll lie flat and relax. If you’re doing a stress test, you’ll walk on a treadmill or pedal on a stationary bike.

It takes about 10 minutes to attach the electrodes and complete a resting EKG test. But the actual recording takes only 10 seconds. An EKG that’s part of an exercise stress test may take longer.

A computer creates a picture (on graph paper or a screen) of the electrical impulses traveling through your heart. The impulses form a wave pattern that your healthcare provider can look at. You won’t feel anything different when the electrodes communicate with the computer.

The electrodes will stay on your skin until the EKG test is done. Then, your provider will remove them, and you can return to your normal activities.

What are the risks of this test?

An electrocardiogram is a low-risk test. It doesn’t use radiation or put electricity into your skin. You might have some skin irritation after your healthcare provider removes the sticky patches that were attached to the sensors.

What type of results do you get and what do the results mean?

An EKG test produces a picture of your heart’s electrical activity. Your healthcare provider will “read” this picture to see how much electrical activity there is and how strong it is. They’ll also look at how much time passes between the different waves or peaks that represent the electrical impulses.

A normal EKG should show a regular series of waves that repeat. These include, in order:

1. A small bump (P wave), created by your upper heart chambers (atria)
2. A spike (QRS complex), created by your lower heart chambers (ventricles)
3. Another small bump (T wave), which shows your heart at rest or recovering after beating

These waves should happen again and again with the same distance (which represents time) between them. This means your heart rate is regular and its rhythm is normal.

Unusual wave patterns can mean there’s a problem. Abnormal EKG results can help a provider know which part of your heart has an issue. The process of making your heart beat is a complex one that involves many parts of your heart.

Problems that an EKG can help diagnose include:

• Abnormal heart rhythms (arrhythmias) or abnormal electrical conduction
• Poor blood flow to your heart muscle (ischemia) because of coronary artery disease
• An issue with your heart valves
• Congenital heart disease
• Heart attack
• Enlarged heart chambers
• Heart damage or heart failure

When should I know the results of the test?

If your healthcare provider can review your EKG test results right away, they may speak to you soon afterward. This is especially true when you need treatment immediately. But if your electrocardiogram test is routine or part of a group of tests before a planned surgery, you may not hear from your provider for a few days.

Your provider will keep your EKG records on file to compare with future ones.

If the results are abnormal, what are the next steps?

The next steps depend on why your provider performed the EKG. Based on what they learn, your provider may:

• Adjust your pacemaker settings
• Do other tests to confirm a diagnosis
• Plan treatments, like medications, procedures or surgeries

When should I call my doctor?

Contact your healthcare provider if:

• It’s been several days since your EKG test, and you haven’t heard from them.
• Your symptoms are worse than they were before the test.
• You have questions about the next steps.

EKG vs. ECG — what’s the difference?

You may hear the terms EKG and ECG. Both mean the same thing: an electrocardiogram. EKG comes from the German word, which uses “k” instead of “c.”