Why it's done
By Mayo Clinic staffIf you have signs or symptoms of a heart problem, such as an irregular heartbeat (arrhythmia), your doctor may order a test called an electrocardiogram. An electrocardiogram is a brief, noninvasive test that uses electrodes taped to your chest to check your heart's rhythm.
However, sometimes an electrocardiogram doesn't detect any irregularities in your heart rhythm. If your signs and symptoms suggest that an occasionally irregular heart rhythm may be causing your condition, your doctor may recommend that you wear a Holter monitor for a day or so. The Holter monitor may be able to detect irregularities in your heart rhythm that an electrocardiogram couldn't, since an electrocardiogram usually takes only a few minutes.
Your doctor may also order a Holter monitor if you have a heart condition that increases your risk of an abnormal heart rhythm, such as hypertrophic cardiomyopathy. Your doctor may suggest you wear a Holter monitor for a day or two, even if you haven't had any symptoms of an abnormal heartbeat.
- What are Holter, event, and transtelephonic monitors? American Heart Association. http://www.americanheart.org/presenter.jhtml?identifier=3005149. Accessed Jan. 24, 2011.
- EKG Holter and event monitors. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/holt/holt_all.html. Accessed Jan. 24, 2011.
- Park MK. Pediatric Cardiology for Practitioners. 5th ed. Philadelphia, Pa.: Mosby Elsevier; 2008. http://www.mdconsult.com/das/book/body/121956069-4/807984289/1588/35.html#4-u1.0-B978-0-323-04636-7..50012-5--cesec52_232. Accessed Jan. 26, 2011.

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