title: A New Efficient Method for Detecting Phase Singularity in Cardiac Fibrillation.
abstract: BACKGROUND
  The point of phase singularity (PS) is considered to represent a spiral wave core or a rotor in cardiac fibrillation. Computational efficiency is important for detection of PS in clinical electrophysiology. We developed a novel algorithm for highly efficient and robust detection of PS.
  
  
  METHODS
  In contrast to the conventional method, which calculates PS based on the line integral of the phase around a PS point equal to ±2π (the Iyer-Gray method), the proposed algorithm (the location-centric method) looks for the phase discontinuity point at which PS actually occurs. We tested the efficiency and robustness of these two methods in a two-dimensional mathematical model of atrial fibrillation (AF), with and without remodeling of ionic currents.
  
  
  RESULTS
  1. There was a significant association, in terms of the Hausdorff distance (3.30 ± 0.0 mm), between the PS points measured using the Iyer-Gray and location-centric methods, with almost identical PS trajectories generated by the two methods. 2. For the condition of electrical remodeling of AF (0.3 × ICaL), the PS points calculated by the two methods were satisfactorily co-localized (with the Hausdorff distance of 1.64 ± 0.09 mm). 3. The proposed location-centric method was substantially more efficient than the Iyer-Gray method, with a 28.6-fold and 28.2-fold shorter run times for the control and remodeling scenarios, respectively.
  
  
  CONCLUSIONS
  We propose a new location-centric method for calculating PS, which is robust and more efficient compared with the conventionally used method.
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Young-Seon
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Jun-Seop
authors.initials: JS
authors.lastname: Song
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Minki
authors.initials: M
authors.lastname: Hwang
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Byounghyun
authors.initials: B
authors.lastname: Lim
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Boyoung
authors.initials: B
authors.lastname: Joung
authors.affiliation: Yonsei University Health System, Seoul, Korea.
authors.forename: Hui-Nam
authors.initials: HN
authors.lastname: Pak
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D018780:Body Surface Potential Mapping / Q000379:methods*; D003198:Computer Simulation; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008955:Models, Cardiovascular