Potential role of remote monitoring for scheduled and unscheduled evaluations of patients with an implantable defibrillator

Aims Follow-up of implantable cardioverter defibrillator (ICD) patients, with regular in-office visits every 3-6 months, puts a significant burden on specialized electrophysiology clinics. New technology allows for remote monitoring of device function. We wanted to investigate its potential reliability and to which extent its use can reduce in-office visits. Methods and results We retrospectively analysed data from 1739 prospectively coded ICD visits in a random set of 169 patients (followed between 2 month and 10.4 year in an academic centre). We defined (i) whether the visit was planned or not, (ii) what were the reasons for unplanned visits, (iii) whether any relevant finding was made, (iv) whether a remote monitoring system with the ability or not to detect pacing threshold would have been able to capture the problem, and (v) what actions were taken. The standard follow-up scheme consisted of in-office visits 1 month after implantation and then every 6 months, unless approaching battery depletion. From the 1739 visits, 1530 were performed according to clinical schedule (88%) and in 1197 of those (78.2%), no relevant finding was made. In 0.52% (n = 8) early post-implant pacing threshold increases would not have been detected by remote monitoring without the ability to determine thresholds (although two patients showed a high impedance). Moreover, in 6% of the planned visits, reprogramming would require a consecutive in-office visit (4%) or hospitalization (2%). Only 175 visits (9.6% of all) were conducted prior to the planned follow-up date due to patient symptoms [another 42 (2.4%) were due to planned surgery or safety warnings]. The proportion of relevant findings during unscheduled visits was significantly higher than during scheduled visits (80.6 vs. 21.8%; P < 0.0001) and a higher proportion of those was arrhythmia- and/or device-related (85.1 vs. 55.3%, P < 0.0001). Reprogramming was required more often (33.1 vs. 4%; P < 0.0001) and hospitalization rate was higher (18.3 vs. 2%; P < 0.0001), so that 51.4% of unscheduled visits would require in-office evaluation. Overall, remote follow-up would correctly exclude device function abnormalities or arrhythmic problems in 1402 (82.2%), identify an arrhythmic problem in 262 (15.3%), correctly identify a device-retated problem in 35 (2.1%), but potentially miss an isolated pacing problem in 6 (0.46%). Clinical evaluation would diagnose a relevant clinical problem in the absence of any device interrogation abnormality in 170 patients (10%). Conclusion ICD remote monitoring can potentially diagnose > 99.5% of arrhythmia- or device-related problems if combined with clinical follow-up by the local general practitioner and/or referring cardiologist. It may provide a way to significantly reduce in-office follow-up visits that are a burden for both hospitals and patients.