title: Minimizing discordances in automated classification of fractionated electrograms in human persistent atrial fibrillation.
abstract: Ablation of persistent atrial fibrillation (persAF) targeting complex fractionated atrial electrograms (CFAEs) detected by automated algorithms has produced conflicting outcomes in previous electrophysiological studies. We hypothesize that the differences in these algorithms could lead to discordant CFAE classifications by the available mapping systems, giving rise to potential disparities in CFAE-guided ablation. This study reports the results of a head-to-head comparison of CFAE detection performed by NavX (St. Jude Medical) versus CARTO (Biosense Webster) on the same bipolar electrogram data (797 electrograms) from 18 persAF patients. We propose revised thresholds for both primary and complementary indices to minimize the differences in CFAE classification performed by either system. Using the default thresholds [NavX: CFE-Mean ≤ 120 ms; CARTO: ICL ≥ 7], NavX classified 70 % of the electrograms as CFAEs, while CARTO detected 36 % (Cohen's kappa κ ≈ 0.3, P < 0.0001). Using revised thresholds found using receiver operating characteristic curves [NavX: CFE-Mean ≤ 84 ms, CFE-SD ≤ 47 ms; CARTO: ICL ≥ 4, ACI ≤ 82 ms, SCI ≤ 58 ms], NavX classified 45 %, while CARTO detected 42 % (κ ≈ 0.5, P < 0.0001). Our results show that CFAE target identification is dependent on the system and thresholds used by the electrophysiological study. The thresholds found in this work counterbalance the differences in automated CFAE classification performed by each system. This could facilitate comparisons of CFAE ablation outcomes guided by either NavX or CARTO in future works.
authors.affiliation: Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH, UK.
authors.forename: Tiago P
authors.initials: TP
authors.lastname: Almeida
authors.affiliation: Department of Cardiovascular Science, University of Leicester, Leicester, UK.|University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Gavin S
authors.initials: GS
authors.lastname: Chu
authors.affiliation: Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH, UK.|Biomedical Engineering, Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Santo André, Brazil.
authors.forename: João L
authors.initials: JL
authors.lastname: Salinet
authors.affiliation: Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH, UK.
authors.forename: Frederique J
authors.initials: FJ
authors.lastname: Vanheusden
authors.affiliation: Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH, UK.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Jiun H
authors.initials: JH
authors.lastname: Tuan
authors.affiliation: University Hospitals of Leicester NHS Trust, Leicester, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stafford
authors.affiliation: Department of Cardiovascular Science, University of Leicester, Leicester, UK.|University Hospitals of Leicester NHS Trust, Leicester, UK.|National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester, UK.
authors.forename: G André
authors.initials: GA
authors.lastname: Ng
authors.affiliation: Department of Engineering, University of Leicester, University Road, Leicester, LE1 7RH, UK. fss1@leicester.ac.uk.|National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester, UK. fss1@leicester.ac.uk.
authors.forename: Fernando S
authors.identifier: http://orcid.org/0000-0001-5981-7726
authors.initials: FS
authors.lastname: Schlindwein
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis*; D001331:Automation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Atrial fibrillation; CFAE; Electrogram fractionation; Mapping; Statistical classification; Substrate