What you can expectBy Mayo Clinic staff
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During the procedure
An electrocardiogram can be done in the doctor's office or hospital, and is often performed by a technician. After changing into a hospital gown, you'll lie on an examining table or bed. Electrodes — often 12 to 15 — will be attached to your arms, legs and chest. The electrodes are sticky patches applied with a gel to help detect and conduct the electrical currents of your heart. If you have hair on the parts of your body where the electrodes will be placed, the technician may need to shave the hair so that the electrodes stick properly.
You can breathe normally during the electrocardiogram. Make sure you're warm and ready to lie still, however. Moving, talking or shivering may distort the test results. A standard ECG takes just a few minutes.
If you have a heartbeat irregularity that tends to come and go, it may not be captured during the few minutes a standard ECG is recording. To work around this problem, your doctor may recommend another type of ECG:
- Holter monitoring. Also known as an ambulatory ECG monitor, a Holter monitor records your heart rhythms for an entire 24-hour period. Wires from electrodes on your chest go to a battery-operated recording device carried in your pocket or worn on a belt or shoulder strap. While you're wearing the monitor, you'll keep a diary of your activities and symptoms. Your doctor will compare the diary with the electrical recordings to try to figure out the cause of your symptoms.
- Event recorder. If your symptoms don't occur often, your doctor may suggest wearing an event recorder. This device is similar to a Holter monitor, but it allows you to record your heart rhythm just when the symptoms are happening. You can send the ECG readings to your doctor through your phone line.
- Stress test. If your heart problems occur most often during exercise, your doctor may ask you to walk on a treadmill or ride a stationary bike during an ECG. This is called a stress test. If you have a medical condition that makes it difficult for you to walk, medication may be injected to mimic the effect of exercise on the heart.
After the procedure
Usually, your doctor will be able to tell you the results of your ECG the same day it's performed. If your electrocardiogram is normal, you may not need any other tests. If the results show there's a problem with your heart, you may need a repeat ECG or other diagnostic tests, such as an echocardiogram. Treatment depends on what's causing your signs and symptoms.
- Electrocardiogram. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/ekg/. Accessed Aug. 20, 2012.
- Podrid PJ. Ambulatory monitoring in the assessment of cardiac arrhythmias. http://www.uptodate.com/index. Accessed Aug. 20, 2012.
- Stress testing. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/health-topics/topics/stress/. Accessed Aug. 20, 2012.