Holter monitor

Holter monitor

Holter monitor
Other names	Ambulatory electrocardiography device
Uses	Heart monitor
Inventor	Norman Holter
Related items	Heart rate monitor

In medicine, a Holter monitor (also called an ambulatory device) is a portable device for continuously monitoring various electrical activity of the central nervous system for at least 24 hours. The most common use is for monitoring the heart or ECG, but can also be used for monitoring EEG. Its extended recording period is sometimes useful for observing occasional cardiac arrhythmias or epileptic events (EEG) that would be difficult to identify in a shorter period of time. For patients having more transient symptoms, a cardiac event monitor which can be worn for a month or more can be used.

The Holter monitor is named for Dr. Norman J. Holter who invented telemetric cardiac monitoring in 1949.^[1] Clinical use started in the early 1960s.^[1]

Much like standard electrocardiography (ECG), the Holter monitor records electrical signals from the heart via a series of electrodes attached to the chest. The number and position of electrodes varies by model, but most Holter monitors employ between three and eight. These electrodes are connected to a small piece of equipment that is attached to the patient's belt, and is responsible for keeping a log of the heart's electrical activity throughout the recording period.

Older devices used to use reel to reel tapes or a standard C120 audio cassette and ran at a 2mm/second speed to record the data. Once a recording has been made, it is played back and analysed at 60x speed so 24 hours of recording can be analysed in 24 minutes. More modern units record onto digital flash memory devices. The data are uploaded into a computer which then automatically analyzes the input, counting ECG complexes, calculating summary statistics such as average heart rate, minimum and maximum heart rate, and finding candidate areas in the recording worthy of further study by the technician.

Electrodes should be placed over bones to minimize artifacts from muscular activity.

Both 24 hour and 30 day event recorders are available.

Event diary

In addition to wearing the device, most patients are asked to keep a diary of activities such as running and sleeping, symptoms, and times that their symptoms occur. This information is used by doctors and technicians to rapidly pinpoint problem areas in the large amount of data recorded during the monitoring period.

Gallery

A Holter monitor can be worn for many days without causing significant discomfort.

Canine Holter Monitor with DogLeggs Vest

A Holter monitor with a US quarter dollar coin to show scale

Wearing the monitor

The recording device can be worn on a belt or in a case on a strap worn across the chest. Individuals who want to minimize the visibility of the device can wear layers or bulky clothes so the case is not as obvious. Also, because of the placement of the electrodes, individuals wearing a holter monitor may wish to wear shirts with a high neck.

Generally, the monitors cannot be worn in the shower, although removal of the device and connected electrodes is occasionally permitted. ^[2]

References

External links

• Holter monitor - MedLine Plus
• Holter monitor - Texas Heart Institute
• Holter Monitor information from Children's Hospital Heart Center, Seattle.