What happens during the test?
During an ECG, small electrodes (called "leads") will be placed on your wrists, ankles, and chest. Older machines require a small amount of gel applied to the skin, which allows the electrical impulses of the heart to be more easily transmitted to the ECG leads, while newer machines just use special stickers. Shaving a small amount of hair from the skin (usually chest hair on men) may also be necessary to improve the contact between the lead and the skin. You will be asked to stay still and to stop breathing or breathe softly.
The leads pick up tiny electrical currents that flow through your heart. The electrical signals are carried from the leads to the ECG machine, which converts the signals into patterns of waves. ECG waves show the heart's rate and rhythm, and can give doctors clues about potential heart damage. The ECG machine produces a print-out which is given to the doctor.
The electrocardiogram can be performed in a doctor's office or at the bedside in a hospital. The entire test takes just a few minutes.
If you have chest pain during the test, tell the technician or the doctor. This information is useful when the doctor interprets the test results.
How should I prepare for this test?
Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any medication allergies and medical conditions that you may have.
Ask your doctor or pharmacist whether you need to stop taking any of your medications before the test. Certain medications affect your heart and can influence the patterns of ECG recordings.
What can I expect after the test?
You can return to your normal activities after the ECG has been completed. Call your doctor if you have heart-related symptoms which worsen.
Results
Your cardiologist or family doctor will analyze the patterns of waves on the ECG print-out and will discuss the test results with you. Each chamber of the heart has its own unique pattern, so doctors can see if a certain area of the heart is producing abnormal electrical signals.
Because ECGs record only the electrical activity of your heart while you're at rest, other types of ECGs are sometimes required, such as an exercise stress test. This is because some heart disorders occur when the heart is working harder than normal.
Depending on the test results, your doctor may have follow-up information for you. Make sure to ask any questions you have about the results of your ECG.