Incidence of false-positive transmissions during remote rhythm monitoring with implantable loop recorders.

Background: Implantable loop recorder (ILR) is preferred strategy for prolonged rhythm monitoring.

Objective: The purpose of this study was to report the incidence and causes of false-positive (FP) diagnoses during remote monitoring with ILR.

Methods: During a 4-week study period, all consecutive remote transmissions in patients with ILR (Reveal LINQ, Medtronic) implanted for atrial fibrillation (AF) surveillance, cryptogenic stroke (CS), and syncope were reviewed. A nurse specializing in device management and an electrophysiologist adjudicated all transmissions. Primary endpoint of the study was incidence of FP in patients with AF, CS, and syncope.

Results: A total of 695 remote transmissions (scheduled downloads: 414; Alerts: 281) sent from 559 patients were adjudicated. The majority of patients had ILR for AF surveillance (n = 321), followed by CS (n =168) and syncope (n = 70) with nominal programming for rhythm diagnosis. Incidence of FP transmissions during the study period was 46%, 86%, and 71% in patients with AF, CS, and syncope, respectively. Incidence of FP transmissions was higher in patients with CS and syncope than in patients with AF (P <.001). For scheduled transmissions, primary causes of FP were signal dropout and undersensing; for alert transmissions, primary reasons for FP were premature atrial and ventricular ectopy.

Conclusion: Incidence of FP during remote monitoring with nominal settings on this ILR was substantial, ranging from 46% to 86% depending on the indication for implantation. Adjudication of these transmissions required a considerable time commitment from electrophysiologists and device clinic personnel but would be required to avoid misdiagnosis and potential errors in clinical management.