Site Map

Holter monitor (24h)

Ambulatory electrocardiography; Electrocardiography - ambulatory; Atrial fibrillation - Holter; Flutter - Holter; Tachycardia - Holter; Abnormal heart rhythm - Holter; Arrythmia - Holter; Syncope - Holter; Arrhythmia - Holter

A Holter monitor is a machine that continuously records the heart's rhythms. The monitor is worn for 24 to 48 hours during normal activity.

Images

Holter heart monitor
Heart - section through the middle
Heart - front view
Normal heart rhythm
Conduction system of the heart

How the Test is Performed

Electrodes (small conducting patches) are stuck onto your chest. These are attached by wires to a small recording monitor. You carry the Holter monitor in a pocket or pouch worn around your neck or waist. The monitor runs on batteries.

While you wear the monitor, it records your heart's electrical activity.

It is very important that you accurately record your symptoms and activities so the provider can match them with your Holter monitor findings.

Electrodes must be firmly attached to the chest so the machine gets an accurate recording of the heart's activity.

While wearing the device, avoid:

Continue your normal activities while wearing the monitor. You may be asked to exercise while being monitored if your symptoms have occurred in the past while you were exercising.

How to Prepare for the Test

You do not need to prepare for the test.

Your provider will start the monitor. You'll be told how to replace the electrodes if they fall off or get loose. Contact your provider if the monitor turns off before the end of the test.

Tell your provider if you are allergic to any tape or other adhesives. Make sure you shower or bathe before you start the test. You will not be able to do so while you are wearing a Holter monitor.

How the Test will Feel

This is a painless test. However, some people may need to have their chest shaved so the electrodes can stick.

You must keep the monitor close to your body. This may make it hard for you to sleep.

Occasionally there may be an uncomfortable skin reaction to the sticky electrodes. You should contact your provider's office where it was placed to tell them about it.

Why the Test is Performed

Holter monitoring is used to determine how the heart responds to normal activity. The monitor may also be used:

Heart rhythms which may be recorded include:

Normal Results

Normal variations in heart rate occur with activities. A normal result is no significant changes in heart rhythms or pattern.

What Abnormal Results Mean

Abnormal results may include various arrhythmias such as those listed above. Some changes may mean that the heart is not getting enough oxygen.

Risks

Other than the uncommon skin reaction, there are no risks associated with the test. However, you should be sure not to let the monitor get wet.

Related Information

Electrocardiogram
Heart attack
Arrhythmias
Chest pain
Atrial fibrillation and atrial flutter
Multifocal atrial tachycardia
Paroxysmal supraventricular tachycardia (PSVT)
Heart palpitations
Fainting

References

Curtis AB, Tomaselli GF. Approach to the patient with cardiac arrhythmias. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022:chap 61.

Olgin JE. Approach to the patient with suspected arrhythmia. In: Goldman L, Cooney KA , eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 49.

BACK TO TOP

Review Date: 5/27/2024  

Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo
Health Content Provider
06/01/2025

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complied with the HONcode standard for trustworthy health information from 1995 to 2022, after which HON (Health On the Net, a not-for-profit organization that promoted transparent and reliable health information online) was discontinued.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2024 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.