title: Demonstration of posterior fascicle to myocardial conduction block during ablation of idiopathic left ventricular tachycardia: an electrophysiological predictor of long-term success.
abstract: BACKGROUND
  Idiopathic left ventricular tachycardia (ILVT) is a common form of ventricular tachycardia (VT) in structurally normal heart. Different methods have been proposed for radiofrequency ablation (RFA) of ILVT that have good short-term results but recurrence is higher. Termination of tachycardia during RFA and/or noninduciblity has been the procedural end point.
  
  
  OBJECTIVE
  To describe electrophysiological markers that add to long-term freedom from recurrences.
  
  
  METHODS
  Fifteen patients with ILVT underwent RFA guided by 3-dimensional electroanatomical mapping. After creating a 3-dimensional geometry of the left ventricle (LV), the conduction system of the LV was mapped by tracing from His recording from the left ventricular outflow tract and distally till the fascicles and perifascicular myocardium. VT was induced by using programmed electrical stimulation. Ablation was done targeting the distal posterior fascicle and extended linearly to the surrounding myocardium till conduction block was achieved between the fascicle-Purkinje network and the left ventricular myocardium.
  
  
  RESULTS
  All patients (13 men; mean age 32 ± 9 years) had inducible VTs. The mean tachycardia cycle length was 320 ± 28 ms. Radiofrequency energy was given to the distal posterior fascicle and the myocardium, with an aim to achieve a myocardial-fascicular conduction block in addition to the termination of VT and noninducibility. Ablation was successful in all. No recurrence of tachycardia was seen in any patient on follow-up (20.8 ± 8.5 months).
  
  
  CONCLUSIONS
  Distal posterior fascicle and Purkinje-myocardial junction is an effective target site for ILVT ablation. The demonstration of myocardial to fascicle conduction block serves as an important electrophysiological marker of successful ablation and improved long-term success.
authors: Institute of Cardiac Sciences, Max Superspecialty Hospital, Patparganj, New Delhi, India.
authors: Vikas
authors: V
authors: Kataria
authors: Amitabh
authors: A
authors: Yaduvanshi
authors: Manoj
authors: M
authors: Kumar
authors: Mohan
authors: M
authors: Nair
mesh_terms: D000328:Adult; D018780:Body Surface Potential Mapping; D002036:Bundle of His / Q000503:physiopathology* / Q000601:surgery; D002037:Bundle-Branch Block / Q000503:physiopathology* / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D011690:Purkinje Fibers / Q000503:physiopathology / Q000601:surgery; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery