Abstract 16305: Incidence and Timing of High-Risk Arrhythmias With Long-Term Continuous Ambulatory Electrocardiographic Monitoring

Abstract

Background: Ambulatory electrocardiographic (ECG) monitoring is the standard of care to screen patients for arrhythmias. However, there is marked variation in the technological features and patient adherence among different ECG monitoring systems. We evaluated a novel adhesive, wireless, single-lead, full-disclosure, up to 14-day ECG monitoring system to measure the burden and timing of high-risk arrhythmias. Methods: We examined data from 122,815 long term continuous ambulatory ECG Monitors. (ZIO® Patch Service, iRhythm Technologies, San Francisco, CA) from 2011-2013 and categorized high-risk arrhythmias into two types: (1) ventricular arrhythmias including non-sustained and sustained ventricular tachycardia and (2) high risk bradyarrhythmias including sinus pauses >3 seconds, atrial fibrillation pauses >5 seconds, and high grade heart block including Mobitz Type II or third-degree heart block. We calculated the proportion of patients with each arrhythmia and the elapsed wear time until each arrhythmia. Results: Of 122,815 Ziopatch recordings, median wear time was 9.9 (IQR 6.8-13.8) days and median analyzable time was 9.1 (IQR 6.4-13.1) days. There were 22,443 (18.3%) with at least one episode of non-sustained ventricular tachycardia (NSVT), 238 (0.2%) with sustained VT, 1,766 (1.4%) with a sinus pause >3 seconds (SP), 520 (0.4%) with a pause during atrial fibrillation >5 seconds (AFP), and 1,486 (1.2%) with high-grade heart block. Median time to first arrhythmia was 74 hours (IQR 26 -149 hours) for NSVT, 22 hours (IQR 5-73 hours) for sustained VT, 22 hours (IQR 7-64 hours) for SP, 31 hours (IQR 11-82 hours) for AFP, and 40 hours (SD 10-118 hours) for high-grade heart block. The yield over time is shown in the Figure 1. Conclusions: A significant percentage of high-risk arrhythmias can be identified by long term continuous monitoring for longer than 24 to 48 hours. The clinical impact from better identification of high-risk arrhythmias warrants further study.