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Updated: Jun 21, 2026

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Undersensing of ventricular fibrillation due to interference between a pacemaker and defibrillator in the same
Lieve Van Casteren1, Wim Huybrechts, Rik Willems
1Department of Cardiology-Electrophysiology, University Hospitals Leuven, Herestraat 49, B-3000 Leuven, Belgium.
Abstract:
Sensing in pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) is crucial to normal device behaviour. Since both devices treat different arrhythmias, the technical approach to signal detection is also completely different. A PM has a fixed threshold of sensing, above which events are sensed and therapy of the device withheld. On the other hand, the defibrillator has a variable threshold of sensing to detect tachyarrhythmias, with sometimes very small and changing electrogram amplitudes. In this case report, we describe interference between a PM and an ICD caused by these differences in the detection of cardiac events, leading to undersensing of ventricular fibrillation at defibrillation threshold testing.
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