Ambulatory ECG Monitoring (Holter Monitor and Patient-Activated Event Recorder)

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Effective Date: April 15, 2013

Recommendations and Topics


This guideline applies to the use of ambulatory electrocardiography (ECG) monitors to detect arrhythmias for adults aged ≥19 years. This is not intended to be a guideline on the diagnosis and management of arrhythmias.


Key Recommendations

  • Ambulatory ECG monitoring should only be ordered after a thorough clinical evaluation, risk assessment, and baseline ECG have been completed.
  • Use of Holter monitoring should be limited to: investigating a patient with frequent symptoms, assessing the risk of a patient in a special population (see below), or monitoring a patient’s response to therapy.
  • If the initial ­Holter monitoring is inconclusive due to low frequency of symptoms, a repeated Holter monitoring may not be appropriate and second line investigations should be considered.


Ambulatory ECG monitoring uses electrocardiographic recorders (Holter monitors and other devices) to document the cardiac rhythm of a patient during their daily activities over an extended period of time. They are used to detect, document and characterize patients’ cardiac rhythm abnormalities.

The main indications for ambulatory ECG monitoring include detection and characterization of arrhythmias to: 1,2

  • attempt to correlate a possible arrhythmia with patient symptoms: palpitations; syncope, near syncope or episodic dizziness; and/or other cardiac symptoms (e.g., shortness of breath, chest pain, episodic fatigue, or diaphoresis)
  • determine the risk of the arrhythmia in the individual clinical setting
  • detect, assess and manage atrial fibrillation
  • monitor the efficacy of pharmaceutical therapy (e.g., antiarrhythmic therapy)

Special populations:

Patients with conditions that may require documentation of an arrhythmia can include:

  1. Structural heart disease (e.g., post myocardial infarction (MI), cardiomyopathy, valvular disease)
  2. Primary electrical heart disease (e.g., sick sinus syndrome, cardiac conduction disease, Wolff-Parkinson-White syndrome (WPW))
  3. Family history of sudden death or arrhythmia
  4. Subjective complaints of symptoms

When is ambulatory ECG monitoring inappropriate?

  • Patients requiring an emergency assessment without delay. These include patients who are at immediate risk of life threatening arrhythmia, injury or sudden death, or arrhythmia causing ischemic chest pain, and pulmonary edema.
  • Patients with symptoms such as chest pain which may be due solely to coronary artery disease. Other investigations such as stress testing are more reliable for diagnosing coronary artery disease.

Which ambulatory ECG monitoring test should be ordered?

  • Choice of device depends on:
    • the type and frequency of patient’s symptom(s);
    • thes ability of the patient (e.g., to activate a device while having symptoms, to fill out a diary); and
    • the accessibility of the device.
  • Holter monitoring should only be used as a first line investigation: in a patient with frequent symptoms, for assessing the risk of a patient in a special population (see above), or for monitoring a patient’s response to therapy.
  • Based on frequency of symptoms, repeated Holter monitoring may not be appropriate and second line investigations should be considered (see table below).
  • Consultation with an internist/cardiologist can help determine which device is best suited to the clinical scenario. The consultant may help arrange the test.
Device Frequency of Symptoms
Device Characteristics
Duration of Test3 Yielda
(mainly palpitations)
External device worn constantly, with continuous tape recording which is retrieved and interpreted once the device is returned.

Only suitable for patients with symptoms occurring within the monitoring period, or when establishing risk/response to therapy.
24 hoursb Syncope
Arrhythmia ~35%3
Weekly to monthly External device worn intermittently, stores data when activated by patient during an event.

Not suitable when investigating syncope since a patient cannot activate it if suddenly unconscious.
Up to a month Arrhythmia
Weekly to monthly External device worn constantly, with memory loop recording capability. The data is stored before and after the patient activates the device. There is also a built-in automatic trigger algorithm that allows the device to store data for asymptomatic arrhythmias.

Suitable as a first line investigation for patients suspected with an arrhythmic cause for syncope.   
Up to a month Syncope5
Less than monthly Device is subcutaneously implanted, with a loop memory recording that stores data once it is manually activated by the patient or activated automatically.

Suitable for patients with spontaneous symptoms with recurrent unexplained syncope.
Up to 3 years Syncope6
a Diagnostic yields are only approximate since they are depended on many variables.
b In some circumstances, the duration of a Holter monitoring can be extended. However, the diagnostic yield of an extended time or repeat test is low.
c These tests are usually arranged in consultation with a specialist.


What is the accessibility of these devices?

  • Holter monitoring is usually arranged by the primary care provider, whereas the other types of tests are usually arranged in consultation with a specialist.
  • Accessibility of these devices may vary depending on community and hospital.
  • Locations of ambulatory ECG can be accessed through Healthlink, or contacting your local lab, private clinics and hospital.
  • Locations may provide patient guides on their websites.

What is the diagnostic value of ambulatory ECG monitoring? 4,7

  • The key to the diagnostic value of ambulatory ECG monitoring is the correlation between symptoms and the timing of the arrhythmia.
  • If no symptoms are present but an arrhythmia documented, there is likely an asymptomatic arrhythmia.
  • If symptoms are present but no arrhythmia documented, an arrhythmia can likely be excluded as the mechanism.
  • If no symptoms are present during the monitoring period and no arrhythmia documented, the test is considered non-diagnostic to the symptoms. 
  Arrhythmia documented during monitoring
Yes No
Symptoms present during monitoring Yes Symptoms attributable to arrhythmia Arrhythmia as cause of symptoms likely excluded
No Asymptomatic arrhythmia Test non-diagnostic


Can ambulatory ECG monitoring be performed on pediatric patients? 2

  • Though outside of this guideline’s scope, ambulatory ECG monitoring can be performed on patients under the age of 19.
  • Indications for monitoring and selection of devices are similar to adults, but you may want to consult with a pediatrician/cardiologist.



  1. Podrid PJ. Ambulatory monitoring in the assessment of cardiac arrhythmias. In: Zimetbaum PJ, Downey BC, editors. MA: UpToDate; 2012.
  2. Crawford MH, Bernstein SJ, Deedwania PC, et al. ACC/AHA Guidelines for ambulatory electrocardiography: A report of the American College of Cardiology/American Heart Association Task Force of practice guidelines. J Am Col Cardiol. 1999;34:912-948.
  3. Zimethbaum P, Goldman A. Ambulatory arrhythmia monitoring: Choosing the right device. Circulation. 2010;122:1629-1636.
  4. Raviele A, Giadda F, Bergfeldt L, et al. Management of patients with palpitations: A position paper from the European Heart Rhythm Association. Europace. 2011;13:920-934.
  5. Angaran P, Klein GJ, Yee R, et al. Syncope. Neurol Clin. 2011;29:903-925.
  6. Edvardsson N, Frykman V, van Mechelen R, et al. Use of an implantable loop recorder to increase the diagnostic yield in unexplained syncope: Results from the PICTURE registry. Europace. 2011;13:262-269.
  7. Moya A, Sutton R, Ammirati F, et al. Guidelines for the diagnosis and management of syncope of the European Society of Cardiology (ESC). Eur Heart J. 2009:30;2631-2671.


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This guideline is based on scientific evidence current as of the Effective Date.

This guideline was developed by the Guidelines and Protocols Advisory Committee, approved by the British Columbia Medical Association, and adopted by the Medical Services Commission.

The principles of the Guidelines and Protocols Advisory Committee are to:

  • encourage appropriate
    responses to common
    medical situations
  • recommend actions
    that are sufficient
    and efficient, neither
    excessive nor deficient
  • permit exceptions
    when justified by
    clinical circumstances.

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