Performance of an implantable automatic atrial fibrillation detection device: impact of software adjustments and relevance of manual episode analysis

Charlotte Eitel, Daniela Husser, Gerhard Hindricks, Manuela Frühauf, Sebastian Hilbert, Arash Arya, Thomas Gaspar, Ulrike Wetzel, Andreas Bollmann, Christopher Piorkowski, Charlotte Eitel, Daniela Husser, Gerhard Hindricks, Manuela Frühauf, Sebastian Hilbert, Arash Arya, Thomas Gaspar, Ulrike Wetzel, Andreas Bollmann, Christopher Piorkowski

Abstract

Aims: Implantable loop recorders (ILRs) with specific atrial fibrillation (AF) detection algorithms (ILR-AF) have been developed for continuous AF monitoring. We sought to analyse the clinical value of a new AF monitoring device and to compare it to serial 7-day Holter.

Methods and results: Sixty-four consecutive patients suffering from paroxysmal AF were included in this prospective analysis and received an ILR-AF. Manual electrogram analysis was performed for each automatically detected episode and each was categorized into one of three possible diagnoses: 'no AF', 'definite AF', and 'possible AF' (non-diagnostic). Analysis was performed separately before and after a software upgrade that was introduced during the course of the study. A subgroup of patients (51 of 64) underwent AF catheter ablation with subsequent serial 7-day Holter in comparison with the ILR-AF. A total of 333 interrogations were performed (203 before and 130 after software upgrade). The number of patients with AF misdetection was significantly reduced from 72 to 44% following the software upgrade (P = 0.001). The number of patients with non-diagnostic interrogations went from 38 to 16% (P = 0.001). Compared with serial 7-day Holter, the ILR-AF had a tendency to detect a higher number of patients with AF recurrences (31 vs. 24%; P = 0.125).

Conclusions: The rate of AF detection on ILR-AF may be higher compared with standard AF monitoring. However, false-positive AF recordings hamper the clinical value. Developments in device technology and device handling are necessary to minimize non-diagnostic interrogations.

Figures

Figure 1
Figure 1
(A) Device stored electrogram with correctly classified atrial fibrillation. (B) Device stored electrogram with misclassified AF (red arrows) due to myopotentials (upper panel) and PAC (lower panel).
Figure 2
Figure 2
(A and B) Clinical classification of interrogations before and after software upgrade.
Figure 3
Figure 3
Clinical classification of patients before and after the software upgrade.

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