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Holter Monitoring


Ambulatory electrocardiography, commonly known as Holter monitoring after its originator, provides a continuous record of the electrical activity of the heart over a 24 or 48 hour period.


A Holter monitor is a portable device small enough to be worn by a patient during normal activity. It consists of an electrocardiograph and a recording system capable of storing 24 hours or more of the individual's ECG record. It is particularly useful in obtaining a record of cardiac arrhythmia that would not be discovered by means of an ECG record of only a few minutes duration.

In some cases, a physician may want to know what happens to an individual's heart rate over a longer period of time than can be measured with an electrocardiogram in a single office visit. The Holter monitor provides a means of recording an ECG continuously on a small cassette tape, usually for 24 hours, while the patient goes through normal daily activities.

Potentially serious arrhythmias (irregularities in heartbeat) are the primary indication for using a Holter monitor, although it is increasingly used in the diagnosis of silent ischemia (deficiency of flow and oxygen due to functional constriction or obstruction of blood vessels).

Holter monitoring involves no risk or discomfort. There is no special preparation for the test, although men may need to have small areas of the chest shaved. Patients can carry on their normal daily activities, although they may avoid showering.


What kind of monitor will be worn?

How accurate is the monitor?

How detailed does the diary need to be? Or how often does an entry need to be made?

What kinds of symptoms should be written in the diary?

What kind of irregularities might show up in the results?

What should be done if an electrode becomes loose?

What is an event recorder?