title: Wave similarity of human ventricular fibrillation from bipolar electrograms.
abstract: OBJECTIVE
  The aim of this report was to review existing techniques for assessment of directionality in fibrillation and to describe the concept of wave similarity analysis in human VF.
  
  
  METHODS
  We applied a technique called wave similarity analysis to bipolar electrograms to study directionality during various rhythms (sinus rhythm, ventricular tachycardia and ventricular fibrillation) in humans. This technique uses the barycentre to determine the activation time and a similarity index is calculated using a technique described previously for AF studies.
  
  
  RESULTS
  We show here that using the wave similarity concept it is possible to recognize myocardial regions that are activated from multiple directions and differentiate those areas from regions that are activated by wave fronts in similar direction or at the exact mirror angle in ventricular fibrillation.
  
  
  CONCLUSIONS
  Wave similarity analysis provides a tool for assessing directional organization in human VF. This analysis of directional organization may have implications for the study of mechanisms of VF in the clinical arena.
authors.affiliation: University of Toronto, Toronto, Ontario, Canada.
authors.forename: Stephane
authors.initials: S
authors.lastname: Masse
authors.forename: Eugene
authors.initials: E
authors.lastname: Downar
authors.forename: Vijay
authors.initials: V
authors.lastname: Chauhan
authors.forename: Elias
authors.initials: E
authors.lastname: Sevaptsidis
authors.forename: Kumaraswamy
authors.initials: K
authors.lastname: Nanthakumar
mesh_terms: D004562:Electrocardiography / Q000379:methods / Q000706:statistics & numerical data*; D004566:Electrodes; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D006321:Heart / Q000502:physiology; D006801:Humans; D008433:Mathematics; D008962:Models, Theoretical; D017180:Tachycardia, Ventricular / Q000503:physiopathology; D014693:Ventricular Fibrillation / Q000503:physiopathology*