A Holter monitor is a device that records every heart beat for 24 or 48 hours. It is about the size of an old fashioned portable tape recorder (Walkman) and is worn on a belt. There are five ECG leads attached to the recorder, running under the clothes and connected to the skin by standard ECG tabs. The positioning of the wires is illustrated in the photograph.
The device is put on to the patient in the Cardiology Department and then the patient goes home and carries on their normal daily activities before returning either a day or two later to have the monitor removed. The time taken to put the machine on and off is about 10 to 15 minutes.
All the heart activity is recorder onto a standard recording tape which then has to be analysed. This can take some time, which is perhaps not surprising given that we all have around 80-120,000 heart beats a day!
This is a very useful device for seeing whether a patient is getting any asymptomatic AF as well showing the doctors what the heart rhythm is during any symptoms that the patient experiences. We give the patients a small diary card to note the time and nature of any symptomatic palpitations which is invaluable in correlating the patient's symptoms to the heart rhythm (if the patient actually fills in the card!).