Abstract 13201: Atrial Fibrillation Detection in Community Ischemic Stroke Patients is Improved With Implantable Cardiac Monitors

Abstract

Introduction: Although implantable cardiac monitors (ICM) improve atrial fibrillation (AF) detection relative to Holters or other extended ambulatory cardiac monitors (EACMs) (e.g., 30-day event monitors or outpatient telemetry) in clinical trials, data are limited on their performance in the community setting. We investigated AF detection in ischemic stroke patients and subsequent initiation of oral anticoagulation (OAC) in a real-world setting. Methods: We identified patients with ischemic stroke (2010-2015) in IBM MarketScan, a national prospectively acquired data set in whom Holters, EACMs, or ICMs were ordered. We further selected patients with no prior history of AF or OAC and continuous database enrollment 6 mos pre- and 24 mos post monitoring. Propensity score matching (PSM) was used to adjust for baseline characteristics differences between monitoring types. Logrank test was used to compare the Kaplan-Meier (KM) curves for AF detection and OAC initiation in patients with AF. Results: A total of 6,287 patients were analyzed: 4,107 Holter (age 63±14 yrs, 46% female, 28% coronary artery disease [CAD], 71% hypertension [HTN]), 1,829 EACM (age 61±14 yrs, 49% female, 27% CAD, 73% HTN), and 351 implanted with ICM (age 63±13 yrs, 51% female, 38% CAD, 82% HTN). After 1:1 PSM, the Holter-ICM cohort comprised of 664 patients and the EACM-ICM cohort comprised of 676 patients. In the Holter-ICM pair, 2 yr AF diagnoses rate was 14.5% for Holter vs 38.3% for ICM (logrank p<0.01, Panel A). In the EACM-ICM pair, 2 yr AF diagnoses rate was 15.4% for EACM vs 38.2% for ICM (logrank p<0.01, Panel B). Initiation of OAC in AF patients by 2 yrs was 41.7% for Holters vs 49.6% for ICMs (logrank p=0.30, Panel C) and 61.5% for EACM vs 49.6% for ICM (logrank p=0.16, Panel D). Conclusion: In community patients with ischemic stroke with no history of AF or prior OAC, rates of OAC initiation are comparable between monitoring types when AF is detected, and ICM outperforms Holter and EACM for the detection of AF.