An electrocardiogram is a simple, painless test that measures
your heart’s electrical activity. It’s also known as an ECG or EKG. Every
heartbeat is triggered by an electrical signal that starts at the top of your
heart and travels to the bottom. Heart problems often affect the electrical
activity of your heart. Your doctor may recommend an EKG if you’re experiencing
symptoms or signs that may suggest a heart problem, including:
- pain in your chest
- trouble breathing
- feeling tired or weak
- pounding, racing or fluttering of your heart
- a feeling that your heart is beating unevenly
- detection of unusual sounds when your doctor
listens to your heart
An EKG will help your doctor determine the cause of your symptoms
along with what type of treatment might be necessary.
If you’re 50 or older or if you have a family history of heart
disease, your doctor may also order an EKG to look for early signs of heart
What Happens During an Electrocardiogram?
An electrocardiogram is quick, painless, and harmless. After you
change into a gown, a technician attaches 12 to 15 soft electrodes with a gel
to your chest, arms, and legs. The technician may have to shave small areas to
ensure the electrodes stick properly to your skin. Each electrode is about the
size of a quarter. These electrodes are attached to electrical leads (wires),
which are then attached to the EKG machine.
During the test, you’ll need to lie still on a table while the
machine records your heart’s electrical activity and places the information on
a graph. Make sure to lie as still as possible and breathe normally. You
shouldn’t talk during the test.
After the procedure, the electrodes are removed and discarded.
The entire procedure takes about 10 minutes.
Types of Electrocardiograms
An electrocardiogram records a picture of your heart’s electrical
activity for the time that you’re being monitored. However, some heart problems
come and go. In these cases, you may need longer or more specialized
Some heart problems only appear during exercise. During stress
testing, you’ll have an EKG while you’re exercising. Typically this test is
done while you’re on a treadmill or stationary bicycle.
Also known as an ambulatory ECG or EKG monitor, a Holter monitor
records your heart’s activity over 24 to 48 hours while you maintain a diary of
your activity to help your doctor identify the cause of your symptoms.
Electrodes attached to your chest record information on a portable,
battery-operated monitor that you can carry in your pocket, on your belt, or on
a shoulder strap.
Symptoms that don’t happen very often may require an event
recorder. It’s similar to a Holter monitor, but it records your heart’s
electrical activity just when symptoms occur. Some event recorders activate
automatically when they detect symptoms. Other event recorders require you to push
a button when you feel symptoms. You can send the information directly to your
doctor over a phone line.
What Risks Are Involved?
There are few, if any, risks related to an EKG. Some people may
experience a skin rash where electrodes were placed, but this usually goes away
People undergoing a stress test may be at risk for heart attack,
but this is related to the exercise, not the EKG.
An EKG simply monitors the electrical activity of your heart. It
doesn’t emit any electricity and is completely safe.
Getting Ready for Your EKG
Avoid drinking cold water or exercising before your EKG. Drinking
cold water can cause changes in the electrical patterns that the test records.
Exercise can increase your heart rate and affect the test results.
Interpreting the Results of an EKG
If your EKG shows normal results, your doctor will likely go over
them with you at a follow-up visit.
Your doctor will contact you immediately if your EKG shows signs
of serious health problems.
An EKG can help your doctor determine if:
- your heart is beating too fast, too slow, or
- you’re having a heart attack or you’ve previously
had a heart attack
- you have heart defects, including an enlarged
heart, a lack of blood flow, or birth defects
- you have problems with your heart’s valves
- you have blocked arteries, or coronary artery
Your doctor will use the results of your EKG to determine if any
medications or treatment can improve your heart’s condition.