title: An activation-repolarization time metric to predict localized regions of high susceptibility to reentry.
abstract: BACKGROUND
  Initiation of reentrant ventricular tachycardia (VT) involves complex interactions between front and tail of the activation wave. Recent experimental work has identified the time interval between S2 repolarization proximal to a line of functional block and S2 activation at the adjacent distal side as a critical determinant of reentry.
  
  
  OBJECTIVE
  We hypothesized that (1) an algorithm could be developed to generate a spatial map of this interval ("reentry vulnerability index" [RVI]), (2) this would accurately identify a site of reentry without the need to actually induce the arrhythmia, and (3) it would be possible to generate an RVI map in patients during routine clinical procedures.
  
  
  METHODS
  An algorithm was developed that calculated RVI between all pairs of electrodes within a given radius.
  
  
  RESULTS
  The algorithm successfully identified the region with increased susceptibility to reentry in an established Langendorff pig heart model and the site of reentry and rotor formation in an optically mapped sheep ventricular preparation and computational simulations. The feasibility of RVI mapping was evaluated during a clinical procedure by coregistering with cardiac anatomy and physiology of a patient undergoing VT ablation.
  
  
  CONCLUSIONS
  We developed an algorithm to calculate a reentry vulnerability index from intervals between local repolarization and activation. The algorithm accurately identified the region of reentry in 2 animal models of functional reentry. The clinical application was demonstrated in a patient with VT and identified the area of reentry without the need of inducing the arrhythmia.
authors: Division of Imaging Sciences, King's College London, London, United Kingdom. Electronic address: nchild@hotmail.com.
authors: Nicholas
authors: N
authors: Child
authors: Division of Imaging Sciences, King's College London, London, United Kingdom.
authors: Martin J
authors: MJ
authors: Bishop
authors: Department of Mechanical Engineering, University College London, London, United Kingdom.
authors: Ben
authors: B
authors: Hanson
authors: Academic Medical Center, Amsterdam, The Netherlands; L'Institut de RYthmologieet de Modelisation Cardiaque (LIRYC), Fondation Université Bordeaux, Bordeaux, France.
authors: Ruben
authors: R
authors: Coronel
authors: Academic Medical Center, Amsterdam, The Netherlands.
authors: Tobias
authors: T
authors: Opthof
authors: Department of Biomedical Engineering, George Washington University, Washington, DC.
authors: Bastiaan J
authors: BJ
authors: Boukens
authors: L'Institut de RYthmologieet de Modelisation Cardiaque (LIRYC), Fondation Université Bordeaux, Bordeaux, France; INSERM, Universite de Bordeaux, Centre Recherche, Cario-Thoracique de Bordeaux U1045, Bordeaux, France.
authors: Richard D
authors: RD
authors: Walton
authors: L'Institut de RYthmologieet de Modelisation Cardiaque (LIRYC), Fondation Université Bordeaux, Bordeaux, France; Department of Biomedical Engineering, George Washington University, Washington, DC; Department of Biomedical Engineering, Washington University, St Louis, Missouri.
authors: Igor R
authors: IR
authors: Efimov
authors: Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom.
authors: Julian
authors: J
authors: Bostock
authors: Division of Imaging Sciences, King's College London, London, United Kingdom.
authors: Yolanda
authors: Y
authors: Hill
authors: Department of Cardiology, Guy's and St Thomas' Hospital, London, United Kingdom.
authors: Christopher A
authors: CA
authors: Rinaldi
authors: Division of Imaging Sciences, King's College London, London, United Kingdom.
authors: Reza
authors: R
authors: Razavi
authors: Division of Imaging Sciences, King's College London, London, United Kingdom.
authors: Jaswinder
authors: J
authors: Gill
authors: Department of Cardiovascular Sciences, University College London, London, United Kingdom.
authors: Peter
authors: P
authors: Taggart
mesh_terms: D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D004198:Disease Susceptibility / Q000175:diagnosis / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D023421:Models, Animal; D008955:Models, Cardiovascular; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012756:Sheep; D013552:Swine; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology
keywords: Ablation; Arrhythmia; Ventricular tachycardia