The Electrocardiogram (ECG or EKG)
If your healthcare provider suspects a problem in your heart's electrical system, you may be scheduled for an electrocardiogram (ECG or EKG).
An electrocardiogram (ECG) test helps your healthcare provider understand what your heart rhythm is and where it comes from. In other words, how the heart’s electrical system sends impulses from the atrium to the ventricle.
An ECG test looks at:
- the heart rate
- the shape the heart signal
- the timing between the atrium and the ventricle
Three kinds of tests record your heart’s electrical activity from outside the body, each for a different period of time:
- An electrocardiogram (ECG) is done in the healthcare provider’s office. It records your heart rhythm for a few minutes.
- A Holter Monitor records and stores (in its memory) all of your heart rhythms for 24-72 hours.
- An Event Recorder records and stores your heart rhythms (in its memory) only when you push a button.
Did you know:
You may hear someone say ECG or EKG. ECG is a short way to say “electrocardiogram.” EKG is for the German word “electrokardiogram.” Both terms are used.
What to Expect
Recording an ECG is painless, takes just a few minutes, and can be done in a healthcare provider's office.
When you have an ECG test you may be asked to open your shirt or remove your clothes from the waist up, and lie on an exam table.
As many as 12 small sticky patches called electrodes are placed on your chest, neck, arms, or legs. The electrodes connect to wires on the ECG machine. They sense the heart’s electrical signals from the surface of your skin. The machine then traces your heart’s rhythm on a strip of graph paper.
An ECG can also help your healthcare provider diagnose whether:
- you have arrhythmias
- your heart medication is effective
- blocked coronary arteries in your heart are cutting off blood and oxygen to your heart muscle
- your blocked coronary arteries have caused a heart attack