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Paradoxical undersensing at a high sensitivity in dual chamber pacemakers
R Willems1, P Holemans, H Ector
1Department of Cardiology, University Hospital Gasthuisberg, University of Leuven, Leuven, Belgium.
Pacing and Clinical Electrophysiology : PACE
|April 20, 2001
Summary
Pacemakers may misinterpret atrial fibrillation as normal rhythm, leading to incorrect therapy. This study reveals paradoxical undersensing in some devices during high atrial rates, impacting patient management.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Device Technology
Background:
- Accurate detection of high-rate atrial events is crucial for device therapy in atrial arrhythmias.
- Evolving indications for device therapy necessitate reliable pacemaker performance.
Purpose of the Study:
- To investigate the atrial detection capabilities of pacemakers during atrial fibrillation (AF).
- To identify potential causes of inaccurate event detection in pacemakers during high atrial rates.
Main Methods:
- Utilized a sheep model of atrial fibrillation (AF) and an in vitro waveform generator to assess pacemaker behavior.
- Evaluated Thera DR, Diamond, Saphir, and Marathon pacemakers at varying sensitivities.
- Counted annotated atrial-sensed events to chart pacemaker performance.
Main Results:
- Thera DR and Diamond pacemakers exhibited paradoxical undersensing of atrial events during AF at higher sensitivities.
- This undersensing led to inappropriate mode switching and flawed diagnostic data.
- The phenomenon was reproducible in vitro and linked to atrial sensing amplifier ringing.
- Marathon pacemakers did not display this paradoxical behavior.
Conclusions:
- Paradoxical undersensing in certain pacemakers during AF is caused by atrial sensing amplifier ringing.
- This device behavior can compromise accurate diagnostics and therapeutic delivery in patients with paroxysmal AF.
- Device management strategies may need to account for this phenomenon.