Real-World Experience with Insertable Cardiac Monitors to Find Atrial Fibrillation in Cryptogenic Stroke

Abstract

Background: The characteristics of atrial fibrillation (AF) episodes in cryptogenic stroke patients have recently been explored in carefully selected patient populations. However, the incidence of AF among a large, real-world population of patients with an insertable cardiac monitor (ICM) placed for the detection of AF following a cryptogenic stroke has not been investigated. Methods: Patients in the de-identified Medtronic DiscoveryLink™ database who received an ICM (Reveal LINQ™) for the purpose of AF detection following a cryptogenic stroke were included. AF detection rates (episodes ≥2 min) were quantified using Kaplan-Meier survival estimates at 1 and 6 months and compared to the CRYSTAL AF study at 6 months. The time to AF detection and maximum duration of AF episodes were also analyzed. Results: A total of 1,247 patients (age 65.3 ± 13.0 years) were followed for 182 (IQR 182-182) days. A total of 1,521 AF episodes were detected in 147 patients, resulting in AF detection rates of 4.6 and 12.2% at 30 and 182 days, respectively, and representing a 37% relative increase over that reported in the CRYSTAL AF trial at 6 months. The median time to AF detection was 58 (IQR 11-101) days and the median duration of the longest detected AF episode was 3.4 (IQR 0.4-11.8) h. Conclusions: The real-world incidence of AF among patients being monitored with an ICM after a cryptogenic stroke validates the findings of the CRYSTAL AF trial and suggests that continuous cardiac rhythm monitoring for periods longer than the current guideline recommendation of 30 days may be warranted in the evaluation of patients with cryptogenic stroke.

Heart Rhythm Monitoring Strategies for Cryptogenic Stroke: 2015 Diagnostics and Monitoring Stroke Focus Group Report

“…In the CRYSTAL AF study, if monitoring had stopped at 30 days as recommended in the current guidelines, most AF would have been missed, given that the median time from randomization to AF detection was 84 days (interquartile range, 18–265) at 12 months. Furthermore, several studies using insertable cardiac monitors to monitor CS patients have also shown average times to diagnosis longer than 30 days and ranging from 41 to 152 days (Table ) . Future research should characterize the time course for AF detection post‐CS and the progression of AF over time.…”

P- and R-Wave Amplitude Sensed By Reveal LINQ™ Loop Recorder in Pediatric Patients

“…7,8 This algorithm has been validated in adult patients to assist in P-wave detection. 9,10 Further research has demonstrated that a sensed R-wave amplitude of at least 0.2 mV is required for arrhythmia detection.…”

Diagnostic and therapeutic value of implantable loop recorder: A tertiary care center experience

“…Ziegler et al in their review of the de‐identified Medtronic Discovery Link database also detected AF at a median duration of 112 days in 21% of patients postcryptogenic stroke with better results seen using continuous monitoring over intermittent monitoring . Brachmann et al concluded that the longer the time over which continuous monitoring was performed, the higher the yield of diagnosing AF in the CRYSTAL–AF study . Ziegler reproduced the same results in a real‐world cohort .…”