Ambulatory Electrocardiogram (Holter Monitor)

(Also called: Holter monitor)


Also known as an ambulatory ECG or EKG monitor, the Holter monitor is a portable device used to make a continuous recording of your heart rate and rhythm as you go about your daily routine. A cardiologist uses the information from the device to detect heart rhythm abnormalities, determine whether your medications need adjusting, or to match your symptoms with heart activity.

If you have signs and symptoms of an arrhythmia, such as palpitations (episodes of rapid heartbeats) or unexplained fainting or dizziness, your doctor may recommend wearing a Holter monitor for 72 hours to 14 days. Over that period, the Holter monitor will record abnormalities in your heart rate and rhythm. Additionally, you can press the Event button to document when you feel a specific symptom. This helps a cardiologist assess whether your symptoms are related to abnormal electrical activity in your heart.


Your doctor must order this test. Your doctor will fax a requisition to 613-696-7197 or electronically submit a completed form to the Arrhythmia Monitoring Centre to book an appointment. The office staff will contact you with the date and time. A few days before your scheduled appointment, you will receive an automated phone call reminder of your appointment.

If you need to change the appointment date, you can contact the Arrhythmia Monitoring Centre at 613-696-7239.

What to expect at your appointment

  • You will have three small areas on your chest cleaned, marked, and rubbed lightly with fine sandpaper. An electrode will adhere to the skin better if hair is shaved from the area and/or if a special tincture or spray is used. Please ask the technician for hypoallergenic electrodes if you have sensitive skin or if you are allergic to the electrodes.
  • A technician will apply electrodes clipped to wires to each prepared site on your chest. Tape will secure the wires to your skin.
  • The wires and cable are connected to the Holter device. You may clip the device to your clothing or place it in a disposable pouch worn around the neck.
  • The Holter technician will instruct you to press the Event button when experiencing symptoms. The technician may provide you with a diary in which you may record symptoms experienced, including the time and activity level associated with the symptom. If you do not experience symptoms during the monitoring period, return the diary and write “no symptoms” in the diary.
  • A technician will instruct you to remove the monitor at a specified time and to discard the electrodes.
    • Remove the equipment by hand only.
    • Scissors and other sharp tools should not meet the device or the attachments.
    • Do not use sharp tools near any part of the equipment.
  • Place the equipment in a clean bag and return by the time specified. There are two well-identified drop-off boxes in the entrance of the Heart Institute. Please deposit in the box with the least equipment if one of the boxes is overflowing.
  • Once the equipment is returned, a cardiologist will review the data. The cardiologist will send a report to your doctor. Your doctor’s office will notify you of the results.

Patient instructions

Bring a list of all your medications to your appointment, including any vitamins or supplements that you take. Wear comfortable clothing and please arrive 15 minutes before your scheduled appointment.

If you have a hairy chest, you may opt to shave in advance.

It is important to bring the monitor back at the scheduled time. Other patients are waiting.

Additional info