Holter Monitor (Ambulatory ECG)

What is an electrocardiogram (ECG)?

An electrocardiogram (ECG) is a test that records the electrical activity of the heart. It is a non-invasive, painless test.  An ECG may be recommended by the doctor to investigate:

• How fast the heart beats and if the rhythm is normal
• The effect of certain medications or devices (e.g. pacemakers) on the heart rhythm
• The size and position of the heart chambers
• Potential heart disease

What is a Holter Monitor?

A holter monitor is an ambulatory ECG device, that continuously records the heart rhythms while it is being worn by the patient, which is typically over a 24 hour period. For a holter monitor test, electrodes are placed on the chest and connected to a battery-operated recording device carried in the pocket or around the neck on a strap. Whilst wearing the device, patients will be asked to keep a diary of activities and symptoms. The doctor will then compare the diary entries with the electrical recordings to determine the cause of the symptoms.

Preparing for a Holter Monitor Test

No special preparation is needed before the test, although it is advised that patients shower on the morning of the test as they will be unable to shower for the 24 hour duration of the test. Patients should also wear a button down shirt for convenience. Patients will be taught how to reattach the electrodes in case they fall off or become loosened. Patients should advise if they are aware of any allergies to tape or other adhesives.  

While wearing the device, patients should avoid: 

• Electric blankets 
• High-voltage areas
• Magnets
• Metal detectors
• Staying too close to wi-fi sources (such as modems, routers or access points) for extended periods