title: Detection Algorithm of Phase Singularity Using Phase Variance Analysis for Epicardial Optical Mapping Data.
abstract: Spiral reentry is a recognized cause of tachycardia. Detection and tracking of the spiral core are essential for understanding the spiral wave dynamics. The core of the spiral corresponds to a phase singularity (PS), which can be identified in an optical mapping image by a kernel convolution method. However, because of a large number of false positives, this method cannot automatically and stably track the core of sustaining spiral reentry in optical mapping data.
  
  
  
  We developed a new PS detection algorithm that quantifies the variance of phase values in a phase map and identifies the position of PS as its peak.
  
  
  
  In comparison with the kernel convolution method, our method improved the precision of detecting a single sustaining spiral wave core from 73.1% to 99.8%. The precision of the proposed method for virtual-electrode-polarization-induced multiple PSs detections was also higher than the convolutional method.
  
  
  
  The proposed method detects PS by finding the peaks in the phase variance distribution of cardiac optical mapping image. It improved the precision of the core detection of the spiral wave in cardiac optical mapping images in comparison with the conventional kernel convolution method.
  
  
  
  The proposed method will reveal the spiral wave dynamics in optical mapping images better than existing approaches. The objective analysis method of a spiral wave is important for understanding the mechanisms and dynamics of serious heart arrhythmias.
authors.forename: Naoki
authors.initials: N
authors.lastname: Tomii
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Arafune
authors.forename: Haruo
authors.initials: H
authors.lastname: Honjo
authors.forename: Nitaro
authors.initials: N
authors.lastname: Shibata
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakuma
mesh_terms: D000465:Algorithms; D000818:Animals; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D056149:Epicardial Mapping / Q000379:methods*; D006329:Heart Conduction System / Q000503:physiopathology*; D010363:Pattern Recognition, Automated / Q000379:methods; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology*; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods*