What is a Holter ECG?
A Holter ECG is a small, portable heart monitor that you wear while you get on with your normal day. A standard ECG in the rooms records only about ten seconds of your heartbeat, so a problem that comes and goes can easily be missed. The Holter records every heartbeat continuously, usually for twenty-four or forty-eight hours, through sticky patches (electrodes) on the chest connected to a device about the size of a cell phone.
Why is it done?
It is used when your symptoms may be caused by an intermittent rhythm disturbance: palpitations, a racing or skipping heartbeat, dizziness, near-fainting or unexplained tiredness. It also shows whether the heart rate is too slow, whether atrial fibrillation is present or how well it is controlled, whether extra beats are frequent, and whether medication or a pacemaker is doing its job.
What happens on the day?
The electrodes and the monitor are fitted in the rooms. The skin is cleaned and, if necessary, chest hair is trimmed so that the electrodes stay attached. You are then asked to carry on with your usual routine, including work and gentle exercise, and to write down the time and nature of any symptoms in a diary. The monitor must be kept dry, so you can not shower or bath while wearing it. You sleep with it in place. When the recording period is over you return the device to the rooms.
What to expect afterwards
Once the patches are off you can shower normally and there are no restrictions at all. The recording contains hundreds of thousands of beats, so it is analysed by computer and then reviewed beat by beat by a technologist.
Possible complications
The test is very safe, as the monitor only listens to your heart. The usual complaints are minor: itching, redness or an occasional small rash under the electrode patches, and the inconvenience of not being able to shower. Some people find the device uncomfortable to sleep with for the first night.
This information does not replace a consultation. Please discuss your own risks and options with your cardiologist.