Implantable loop recorders in the real world: a study of two Canadian centers

  • Omar A. Ibrahim
  • Doran Drew
  • Christopher J. Hayes
  • William McIntyre
  • Colette M. Seifer
  • Wilma Hopman
  • Benedict Glover
  • Adrian M. Baranchuk



Implantable loop recorders (ILRs) are increasingly being used for ambulatory electrocardiography. We sought to evaluate ILR indications, diagnostic yield, ILR-guided interventions, and complications in two Canadian centers.


This was a retrospective study using electronic medical records to identify ILR implants at Queen’s University and the University of Manitoba. Information was collected on patient characteristics, medications, indication for implant, results of prior investigations, diagnostic outcome, and subsequent management.


A total of 540 patients were identified; 386 had completed monitoring at time of analysis. Forty patients were lost to follow-up. Indications were unexplained syncope 84.8%, palpitations 12.8%, and suspected atrial fibrillation 11.7%. For syncope, ILRs documented arrhythmia or conduction disorder in 46%. Most common conditions were asystole/sinus pause (22%), complete heart block (10.4%), and atrial fibrillation (AF) (6.9%). After ILR diagnosis, 39.9% of implanted patients received pacemaker/ICD and 2.7% underwent catheter ablation. For palpitations, ILRs documented arrhythmia or conduction disorder in 60.4%. Most common conditions were AVNRT, AF, complete heart block, and ventricular tachycardia. After diagnosis, 25% underwent catheter ablation and 22.9% received pacemaker/ICD. For suspected AF, AF was diagnosed in 40%. Complications were observed in 3.3% of implanted patients: implant site infection 1.5%, non-infectious implant site pain requiring device removal or pocket revision 1.5%, 0.2% hypertrophic scar, and 0.2% device malfunction.


An ILR has excellent diagnostic yield for syncope, palpitations, and suspected AF, and a considerable proportion of patients undergo ILR-directed interventions following monitoring. ILR implantation is a low-risk procedure.


Implantable loop recorder Syncope Palpitations Atrial fibrillation 



This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Compliance with ethical standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required.


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Copyright information

© Springer Science+Business Media, LLC 2017

Authors and Affiliations

  • Omar A. Ibrahim
    • 1
  • Doran Drew
    • 1
  • Christopher J. Hayes
    • 2
  • William McIntyre
    • 3
  • Colette M. Seifer
    • 2
  • Wilma Hopman
    • 1
  • Benedict Glover
    • 1
  • Adrian M. Baranchuk
    • 1
    • 4
  1. 1.Department of Cardiology, Kingston General HospitalQueen’s UniversityKingstonCanada
  2. 2.Department of Cardiology, St. Boniface HospitalUniversity of ManitobaWinnipegCanada
  3. 3.Population Health Research InstituteMcMaster UniversityHamiltonCanada
  4. 4.Cardiac Electrophysiology and Pacing, Kingston General HospitalQueen’s UniversityKingstonCanada

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