Who needs a Holter or event monitor?

You may need a Holter or event monitor if your doctor suspects you have an arrhythmia. This is a problem with the speed or rhythm of your heartbeat. Holter or event monitors are most often used to detect arrhythmias in people who have:

• Fainted or sometimes feel dizzy: A monitor may be used if causes other than a heart rhythm problem have been ruled out.
• Palpitations that recur with no known cause: Palpitations are the feeling that your heart is pounding, racing, fluttering, or beating unevenly.

People who are being treated for a heart rhythm problem also may need to use a Holter or event monitor. These monitors can show how treatment is working.

In some people, heart rhythm problems only occur during certain events, such as sleep or physical exertion. Holter and event monitors record the heart rhythm while a person does his or her normal daily routine. This allows the doctor to see how the heart responds to different daily activities, which helps diagnose the problem.

Holter and event monitors also are used for elderly people who may have trouble getting to and from clinics.

This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.