Time until diagnosis of clinical events with different remote monitoring systems in implantable cardioverter-defibrillator patients

Background: Remote monitoring (RM) is an established technology integrated into routine follow-up of patients with an implantable cardioverter-defibrillator (ICD). Current RM systems differ according to transmission frequency and alert definition.

Objective: The purpose of this study was to compare the time difference between detection and acknowledgment of clinically relevant events between 4 RM systems.

Methods: We analyzed time delay between detection of ventricular arrhythmic and technical events by the ICD and acknowledgment by hospital staff in 1802 consecutive patients followed with RM between September 2014 and August 2016. Devices from Biotronik (BIO; n = 374), Boston Scientific (BSC; n = 196), Medtronic (MDT; n = 468), and St Jude Medical (SJM; n = 764) were included. We identified all events from RM web pages and their acknowledgment with RM or at in-clinic follow-up. Events that occurred during weekends were excluded.

Results: We included 3472 events. Proportion of events acknowledged within 24 hours was 72%, 23%, 18%, and 65% with BIO, BSC, MDT, and SJM, respectively, with median times of 13, 222, 163, and 18 hours from detection to acknowledgment (P <.001 for both comparisons between manufacturers). Including only events transmitted as alerts by RM, 72%, 68%, 61%, and 65% for BIO, BSC, MDT and SJM, respectively, were acknowledged within 24 hours. Variation in time to acknowledgment of ventricular tachyarrhythmia episodes not treated with shock therapy was the primary cause for the difference between manufacturers.

Conclusion: Significant and clinically relevant differences in time delay from event detection to acknowledgment exist between RM systems. Varying definitions of which events RM transmits as alerts are important for the differences observed.