Abstract 17325: Initial False Positive Episodes and Outcomes of Programming Changes With a Novel Implantable Loop Recorder

Abstract

Introduction: Management of voluminous data from implantable cardiac devices is resource intensive. False positive events can be especially problematic with implantable loop recorders (ILRs). We sought to describe our early experience with a novel ILR. Hypothesis: Sensitivity adjustment to <=0.10 mV may reduce false positive ILR detection of bradycardia/pauses. Methods: A single center retrospective study was performed in patients with the Abbott Confirm RX ILR. Tachycardia, atrial fibrillation (AF), bradycardia, and pause events were reviewed to determine whether they were true or false positives. Results: The study included 13 patients (age 67 ±15.8 years, 62% men). The reasons for implant included: AF (n=7, 54%), syncope(n=3, 23%), palpitations (n=2, 15%), and stroke (n=1, 8%). The median follow-up duration was 3.1 months (IQR 1.3-4.4 months). There was no change in serial R waves during mean follow-up of 0.58 months (pre 0.62±0.22 mV, post 0.63±0.22 mV, p=0.52). Tachycardia detection occurred in 6 patients (46%), with only 1 patient having a false positive episode. AF detection occurred in 8 patients (62%), with only 2 patients having true AF episodes. Pause/bradycardia episodes were detected in 5 patients (39%), with false positive episodes in 4 patients. There was no difference in R waves at implant among patients with and without false positive bradycardia/pauses episodes (0.66 ±0.27 vs. 0.44 ± 0.28 mV, p=0.21). The max sensitivity was higher among patients with than without false positive bradycardia/pause episodes (0.14 ±0.01, 0.07 ±0.02 mV, p<0.0001). No patients programmed to sensitivity <=0.10 mV had false positive bradycardia/pause episodes. The sensitivity was adjusted to <=0.10 mV in 3 of 4 patients with false positive bradycardia/pause episodes which eliminated future false positive episodes and did not result in false positive tachycardia/AF episodes. The overall mean monthly rate of false positive bradycardia/pause events was reduced from 387 events/month to zero in these patients. Conclusion: Programming the novel ILR to a sensitivity of <=0.10 mV resulted in a marked reduction in false positive bradycardia/pause episodes without an increase in false positive tachycardia/AF episodes.