title: Spatiotemporal correlation between phase singularities and wavebreaks during ventricular fibrillation.
abstract: Phase Singularity and Wavebreak.
  
  
  BACKGROUND
  Phase maps and the detection of phase singularities (PSs) have become a well-developed method for characterizing the organization of ventricular fibrillation (VF). How precisely PS colocalizes with wavebreak (WB) during VF, however, is unknown.
  
  
  RESULTS
  We performed optical mapping of 27 episodes of VF in nine Langendorff-perfused rabbit hearts. A WB is a point where the activation wavefront and the repolarization waveback meet. A PS is a site where its phase is ambiguous and its neighboring pixels exhibit a continuous phase progression from -pi to +pi. The correlation coefficient between the number of WBs and PSs was 0.78 +/- 0.09 for each heart and 0.81 for all VF episodes (P < 0.001), indicating a significant temporal correlation. We then superimposed the WBs and PSs for every 100 frames of each episode. These maps showed a high degree of spatial colocalization. To quantify spatial colocalization, the spatial shifts between the cumulative maps of WBs and PSs in corresponding frames were calculated by automatic alignment to obtain maximum overlap between these two maps. The spatial shifts were 0.04 +/- 0.31 mm on the x-axis and 0.06 +/- 0.27 mm on the y-axis over a 20 x 20 mm2 mapped field, indicating highly significant spatial correlation.
  
  
  CONCLUSIONS
  Phase mapping provides a convenient and robust approach to quantitatively describe wave propagation and organization during VF. The close spatiotemporal correlation between PSs and WBs establishes that PSs are a valid alternate representation of WB during VF and further validated the use of phase mapping in the study of VF dynamics.
authors.affiliation: Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Yen-Bin
authors.initials: YB
authors.lastname: Liu
authors.forename: Anish
authors.initials: A
authors.lastname: Peter
authors.forename: Scott T
authors.initials: ST
authors.lastname: Lamp
authors.forename: James N
authors.initials: JN
authors.lastname: Weiss
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
authors.forename: Shien-Fong
authors.initials: SF
authors.lastname: Lin
mesh_terms: D000200:Action Potentials; D000465:Algorithms; D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004558:Electric Stimulation; D006329:Heart Conduction System / Q000503:physiopathology*; D011817:Rabbits; D013223:Statistics as Topic; D014693:Ventricular Fibrillation / Q000503:physiopathology*