Detection of atrial fibrillation in real world setting in patients with cryptogenic stroke and an implantable loop recorder

Abstract

Introduction: Implantable loop recorders (ILR) are used to screen for atrial fibrillation (AF) in patients with cryptogenic stroke (CS). However, there is limited real-world data regarding the long-term rate of AF detection using ILR and management consequences in patients with CS. The objective is to assess the rate of AF detection in patients with CS in a real-world study over 36 months of follow-up and its consequences on stroke prevention. Methods: This retrospective study included patients with an ILR placed for CS at Baylor College of Medicine and Baylor St. Luke's Medical Center between January 2014 and July 2021. The primary outcome was AF detection in patients with ILR. The secondary outcome was the rate of subsequent strokes after ILR placement in patients with or without diagnosed AF. The AF detection rate in our cohort was compared to the rate in CRYSTAL-AF Trial at 36-month follow-up. The impact of AF detection on clinical management was examined. Results:We identified 225 patients. 51.1% were women and 38.2% African American.Among 85 patients with ILR labeled AF, 43 patients had true AF, and 42 had incorrectly labeled AF (48.3% false positive). The estimated AF detection rate at 36 months followup was 28.6% (95% CI, 26.6%-30.6%). 58.1% of patients with AF were initiated on oral anticoagulation, 80.0% of whom were started on a direct oral anticoagulant. 13.8% of patients had recurrent strokes after ILR implantation; 4 of whom were diagnosed with AF. Conclusion:Compared to CRYSTAL-AF, the AF detection rate in our cohort is similar, but this cohort includes a higher proportion of female and African American patients.Most patients with recurrent strokes after ILR implant did not have AF during 36 months of monitoring.

False‐positive alarms in patients with implantable loop recorder followed by remote monitoring: A systematic review

“…We identified 12 studies as being eligible, of which five prospective studies (two 8,9 and three single-center 10,11,12 ); and seven retrospective studies (two 13,14 and five single-center 15,[16][17][18][19] ). We assigned a star only at those studies with a sample size of at least 100 people.…”

“…The clinical indication for ILR implantation was available for 1830 patients from 11 out of 12 studies included in the analysis. Of 11 studies, eight included patients with cryptogenic stroke (n = 746; 41%) 9,11,12,[14][15][16][17]19 ; five studies included patients in need of AF surveillance for pharmacological optimization (n = 584; 32%) 9,[10][11][12]17 ;…”

“…In 11/12 studies, the ILR-detected episodes were reviewed by trained professionals thought dedicated remote monitoring website 8,9,[11][12][13][14][15][16][17][18][19] ; in 1/12 an electrophysiologist validated the ILR alerts according to the those recoded by PM. 10 5/12 studies (n = 944) focused specifically on FP alarms for AF, 8,12,14,15,18 which was recognized by ILRs analyzing R-R interval variability (represented with a widespread Lorenz Plot distribution 8 or as a variability in R-R duration wider than the variability rate set 15,18 ). In 1/5 study P-wave signal and R-R variability were contextually analyzed by artificial intelligence.…”

“…12 1/5 study did not provide information about AF detection parameters. 14 The other seven studies (n = 2361) evaluated all types of FP (including asystole, bradycardias, tachycardias or high ventricular rate). 9,10,11,13,16,17,19 Overall, 3.305 patients have been screened in the cited articles.…”

“…11,14,16 ThisTA B L E 2Abbreviations: AF, atrial fibrillation; CS, cryptogenic stroke; FP, false positive alarms; HVR, high ventricular rate; ILR, implantable loop recorder; US, unexplained syncope; TIA, transient ischemic attack; SVRD, sudden ventricular rate drop; VT, ventricular tachycardia.…”