P1362Diagnostic accuracy of R-wave detection by insertable cardiac monitors

OnBehalf

1.Department of Cardiology, Ghent University Hospital, Ghent, Belgium

Introduction

Insertable cardiac monitors (ICM) allow automatic arrhythmia detection but the diagnostic performance can be hampered by poor R-wave sensing leading to false positive recordings.

Purpose

This study assesses the prevalence and predictors of R-wave under- and oversensing among different ICM types. 

Methods

Patients implanted with an ICM at the University Hospital of Ghent between January 2017 and August 2018 were included. All ICM tracings recorded at ICM interrogation or transmitted by remote monitoring were reviewed for inadequate R-wave sensing leading to false arrhythmia alerts. Inadequate R wave sensing was defined as undersensing due to sudden reduction in R wave amplitude or oversensing due to the occurrence of artefacts. Patient and implant characteristics were retrieved from the medical record and implant reports.

Results

The study screened 135 patients (age 59 ± 19 years, 44% female) implanted with different ICM types: Reveal XT and LINQ n = 92 (68%), Confirm and Confirm Rx n = 35 (26%),  BioMonitor n = 8 (6%). ICM analysis was conducted in 112 patients (83%). Overall, false arrhythmia alerts due to inadequate R wave sensing occurred in 22 (20%) of the patients. Among these 22 patients, false diagnosis of bradycardia or pauses were documented in 64%, false high ventricular rates in 14% and false atrial fibrillation alerts in 22% of the patients. Of interest, in an additional 7 (6%) patients significant changes in R wave sensing occurred, although not causing false arrhythmic alerts. Occurrence of R-wave changes occurred in 19% of Reveal, 17% of Confirm and 50% of BioMonitor ICMs (p = not significant). Occurrence of R-wave changes among the different types of ICMs were not related to age, sex, BMI, time of the day, heart frequency or implant R-wave sensing.

Conclusion

Poor R wave sensing, leading to false arrhythmia detection, occurred in a significant number of ICM, and seems to occur independent of ICM type, patient or implant characteristics.

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