title: Catheter ablation of haemodynamically unstable or non-sustained ventricular tachycardia.
abstract: BACKGROUND
  Ventricular tachycardia (VT) may be haemodynamically unstable or non-sustained, interfering with detailed activation mapping. Non-contact mapping permits beat-by-beat analysis of VT, projected upon a 3-dimensional reconstructed geometry of the cardiac chamber. Objective - The aim of the present study is to determine the utility of non-contact endocardial mapping to guide ablation of haemodynamically unstable VT or non-sustained VT.
  
  
  RESULTS
  Eighteen VTs in 17 patients were induced (cycle length 336 +/- 58 ms) and mapped. Three patients were mapped during premature ventricular complexes (PVCs) because sustained VT could not be induced. Analysis of the archived non-contact activation maps was performed to identify the exit point and/or the diastolic pathway of theVT reentry circuit. The endocardial exit points (10 +/- 16 ms before QRS) were defined in 17/18 VTs (94%). A diastolic pathway was identified in 5/6 ischaemic VTs. The earliest activation sites were identified in all 3 patients with PVCs. Radiofrequency current was applied around the exit point or to create a line of block across the diastolic pathway. Catheter ablation was performed in 17/18 VTs, including 3 patients mapped using only PVCs. Ablation was successful in 16/18 VTs (89%) and in 1 5/17 patients (82%). Catheter ablation was not performed in one patient (peri-hisian VT) and was unsuccessful in one patient (mapped during PVCs).
  
  
  CONCLUSIONS
  Non-contact endocardial mapping is useful to guide radiofrequency catheter ablation of untolerated or non-sustained VTs.
authors.affiliation: Department of Cardiology, First Affiliated Hospital, Sun Yat-Sen University, No. 58 Zhongshan road 2, GuangZhou 510080, China. wusuhua168@yahoo.com
authors.forename: Suhua
authors.initials: S
authors.lastname: Wu
authors.forename: Walter F
authors.initials: WF
authors.lastname: Kerwin
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Peter
authors.forename: Eli S
authors.initials: ES
authors.lastname: Gang
authors.forename: Hong
authors.initials: H
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D003971:Diastole; D004567:Electrodes, Implanted; D022062:Electrophysiologic Techniques, Cardiac; D004699:Endocardium / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012107:Research Design; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome; D018879:Ventricular Premature Complexes / Q000503:physiopathology / Q000601:surgery