Abstract 13915: Atrial Fibrillation Begets Atrial Fibrillation in Cryptogenic Stroke Patients: Results from the Crystal-AF Trial

Abstract

Introduction: Initial episodes of atrial fibrillation (AF) detected following a cryptogenic stroke (CS) may be brief in duration and the clinical relevance of such episodes is uncertain. Hypothesis: We investigated whether an initial brief episode of AF was predictive of subsequent long duration AF episodes in CS patients (pts) with an insertable cardiac monitor (ICM). Methods: CS pts (n=208, age 61.6±11.3 years, 66% male) randomized to the ICM arm of the CRYSTAL-AF study and inserted with a device (Reveal® XT) were followed for 21±9 months. AF episodes (>30 seconds) were independently adjudicated and the first adjudicated AF episode was classified as brief (<1 hour) or long (≥1 hour). The incidence of subsequent long duration AF episodes among pts with an initially brief episode was computed. The impact of episode duration on prescription of oral anticoagulation (OAC) therapy was also assessed. Results: Among 36 pts with an adjudicated AF episode for which duration information was available, the initial episode was classified as brief in 18 (50%) pts and long in 18 (50%) pts. Among those with initially brief episodes, 10 (56%) experienced only subsequent brief episodes while 8 (44%) went on to experience at least one long AF episode. The median time between the initial brief episode and first long AF episode was 75 days [interquartile range: 27-624 days]. OAC was prescribed in 7/10 pts (70%) with only brief AF episodes compared to 26/26 pts (100%) with at least one long episode of AF (p=0.017). Conclusion: Initial AF episodes in pts with CS are equally likely to be of short or long duration. However, nearly half of CS pts with initially brief episodes of AF subsequently have long duration episodes detected much later via prolonged monitoring with ICMs. Therefore, early detection of brief AF episodes may merit more rigorous monitoring of AF with ICMs since physicians were significantly more likely to prescribe OAC for secondary stroke prevention in response to longer duration episodes.