Event monitoring factsheet


The event monitor is a patient-activated device that records the heart's electrical activity (ECG). The aim of event monitoring is to document and describe abnormal electrical behaviour in the heart.

These can be random, spontaneous, emotionally triggered or exercise induced. They may be life threatening if not detected. 

Event monitoring is particularly useful where symptoms occur irregularly and may not have appeared on other diagnostic tests including ECG and Holter monitoring

Your doctor may recommend an event monitor to assist in:

  • diagnosing a heart-related cause of symptoms such as chest pain, shortness of breath, fainting or dizziness
  • documentation of rhythm disturbance (preferably onset and offset) in patients with palpitations
  • ruling our cardiac issues as a cause for seizures.

 Before the procedure

Your doctor/technician will explain the procedure to you and offer you the opportunity to ask any questions.

The skin must be clean and dry and free from any moisturisers or oils which make it impossible for the electrodes to stick to the skin.

Two electrodes are positioned on the chest one high on the right side and the other on the left side of the rib cage. The leads are then attached to the electrodes. Some monitors may vary. 

Once the lead set is inserted into the monitor, the machine will run preliminary checks on the batteries and memory and will then start scanning. The machine alerts you when the batteries need changing or the memory is full.

There is a small risk of minor skin irritation caused by the electrodes. Your technician will explain how best to avoid this. Please discuss any concerns with your doctor prior to wearing the monitor. You may deny consent at any time.

 During the procedure

The event monitor is a portable device that records the heart's electrical activity (ECG). It only stores the ECG in memory when activated by the patient. 

It is pre-programmed to capture and store a timed amount of ECG before and after the record button is pressed. 

As a minimum standard, the monitor can store five events, each being one minute long (30 secs before and 30 secs after the record button is pressed). 

The monitor may be worn on a belt, in a pocket or clipped to your clothes at your waist. Two adhesive electrodes (stickers) are attached to your chest, which are connected to leads from the machine. 

When the patient feels a symptom, a simple press of the record button stores and records the ECG surrounding the symptoms or event. The patient must  write the date, time, activity and symptoms in the diary provided.

 After the procedure

The recorded data is sent via the telephone. It may be sent after one or multiple episodes have been recorded. 

A full explanation of sending the ECG will be given when you receive your monitor from your cardiac team.

Last updated Wednesday 10th July 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024

This factsheet was produced with support from John Hunter Children's Hospital.