What is a Holter Monitoring?

A Holter monitor is a small, battery-operated, portable, wearable device that measures and tape records your heart beat (rhythm) through ECG (electrocardiography) continuously for 24 hours or longer depending on the type of monitoring device used.  In other words, this small Holter device keeps track of your heart rate and rhythm and records your ECG as you go about your daily activities.

A Holter monitor test is usually performed after a routine traditional test to check your heart rhythm (ECG) does not show up anything abnormal.


Who requires to do a Holter monitor test?

It is usually done when an individual complains of palpitations, “skipped beats”, “jumped beats”, fast or slow fluttering of the heart or irregular heartbeats (arrhythmias) or unexpected fainting.  A regular ECG can only allow the doctor to look at the heart’s activity at one point in time during the ECG recording (lasting a few seconds).  As abnormal heart rhythms can come on and off, at any time of the day or night, the Holter monitor will allow the individual’s heart beat to be recorded over time.


Are there any risks to wearing a Holter monitor?

There are no significant risks involved in wearing a Holter monitor device. There is no radiation and no side effects other than the possibility of skin irritation where the electrodes are placed on the chest and some inconvenience of carrying the device.

Holter monitors are not usually affected by other electrical appliances.  However one should avoid being close to metal detectors, magnets, microwave oven, electric blankets, electric razors and toothbrushes while wearing the monitor device as these can interrupt the signal from the electrodes to the Holter monitor.  Also, keep away from cell phones and portable music players at least 6 inches from the monitor for the same reason.


How is Holter monitor test performed?

Electrodes that sense your heartbeats will be applied by sticking small conducting patches on the chest. They are then attached by wires to a small recording monitor (see figure 1).  The Holter monitor (about the size of a deck of cards) is put in a pocket or pouch and worn around the neck or waist.  You will be given a diary to keep track of your activities and record how you feel (e.g. time when palpitations, skipped heartbeats, shortness of breath, chest pain or light-headedness symptoms occur).  This will allow the cardiologist to compare data of your symptoms with that collected from the Holter monitor recorded and therefore help with the diagnosis of your condition.

An important point to note is once the Holter monitor is in place; you cannot get the monitor wet or remove the device to bathe.

Figure 1


What happens after completion of the duration of the Holter monitoring?

On completion of the monitoring period, the device is returned to the technician.  The information recorded in the monitor will be processed via a computer software program and a report will be generated for the cardiologist to review (figure 2 and 3).  This also includes a correlation with the notes in your diary.  Your cardiologist will then discuss the results with you.

In some cases, the Holter monitoring cannot detect any abnormalities during the duration (usually 24 hours) of the monitoring especially if you did not have any irregular heart rhythm while you wore the monitor.  Your cardiologist may then recommend a wireless Holter monitoring or an event recorder, both of which can be worn longer than the standard Holter monitor.  Event recorders are similar to Holter monitors and generally require you to push a button when you feel symptoms.  There are several different types of event recorders.

Figure 2

Figure 2