title: Identification of the slow conduction zone in a macroreentry circuit of verapamil-sensitive idiopathic left ventricular tachycardia using electroanatomic mapping.
abstract: BACKGROUND
  Although idiopathic left ventricular tachycardia (ILVT) has been shown to possess a slow conduction zone (SCZ), the details of the electrophysiological and anatomic aspects are still not well understood.
  
  
  OBJECTIVE
  We hypothesized that the SCZ can be identified using a 3-dimensional electroanatomic (EA) mapping system.
  
  
  METHODS
  Ten patients with ILVT were mapped using a 3-dimensional electroanatomic (EA) mapping system. After a 3-dimensional endocardial geometry of the left ventricular was created, the conduction system with left Purkinje potential (PP) and the SCZ with diastolic potential (DP) in LV were mapped during sinus rhythm (SR) and ventricular tachycardia (VT) and were tagged as special landmarks in the geometry. The electrophysiological and anatomic aspects of it were investigated.
  
  
  RESULTS
  EA mapping during SR and VT was successfully performed in 7 patients, during VT in 3 patients. The SCZ with DPs located at the inferoposterior septum was found in 7 patients during SR and all patients during VT. The length of the SCZ was 25.2 ± 2.3 mm with conduction velocity 0.08 ± 0.01 m/s. No differences in these parameters were found between patients during SR and VT (P > 0.05). An area with PP was found within the posterior septum. A crossover junction area with DP and PP was found in 7 patients during SR and VT. This area with DP and PP during SR coincided or were in proximity to such area during VT and radiofrequency ablation targeting the site within the area abolished VT in all patients.
  
  
  CONCLUSIONS
  The ILVT substrate within the junction area of the SCZ and the posterior fascicular can be identified and can be used to guide the ablation of ILVT.
authors.affiliation: Clinical EP Laboratory and Arrhythmia Service Center of Fuwai Heart Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Chu
authors.forename: Yufa
authors.initials: Y
authors.lastname: Sun
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Liu
authors.forename: Yuhe
authors.initials: Y
authors.lastname: Jia
authors.forename: Kexiu
authors.initials: K
authors.lastname: Mao
authors.forename: Jielin
authors.initials: J
authors.lastname: Pu
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000200:Action Potentials; D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011690:Purkinje Fibers / Q000187:drug effects / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology*; D056969:Voltage-Sensitive Dye Imaging
chemical_list: D000889:Anti-Arrhythmia Agents; D014700:Verapamil