title: Characteristics of Clinical and Induced Ventricular Tachycardia Throughout Multiple Ablation Procedures.
abstract: BACKGROUND
  Optimal procedure endpoints of catheter ablation for ventricular tachycardia (VT) are not defined and multiple repeat procedures are sometimes required. However, there are few studies to compare the details of repeat procedures to the initial procedure. The aim of this study is to compare the characteristics of clinical and induced VT throughout multiple procedures and clarify their relations.
  
  
  RESULTS
  Of 425 consecutive patients with structural heart disease who underwent catheter VT ablation, second, third and fourth procedures were performed in 101, 23, and 5 patients, respectively. Of 227 VTs that were induced during the second procedure, 68 (30%) VTs had previously been induced at the first procedure. In multivariable analysis, identification of an exit/isthmus site (HR = 0.29, P = 0.047), early termination of VT during radiofrequency application (HR 0.11, P = 0.037) and elimination of target VT at the end of first procedure (HR = 0.43, P = 0.036) were independently associated with noninducibility of the same VT at the second procedure. Over the course of multiple procedures the mean VT cycle length gradually lengthened (381 ± 107, 413 ± 111, 460 ± 124, 507 ± 99 milliseconds in first, second, third, and fourth procedure, respectively, P < 0.001) and more induced VTs became mappable (32%, 40%, 62%, and 70% in first, second, third, and fourth procedure, respectively, P < 0.001).
  
  
  CONCLUSIONS
  Identification and ablation of VT exit/isthmus, early termination of VT during radiofrequency application and elimination of targeted VT are associated with absence of that VT during a repeat procedure, and recurrences are then mostly due to new VTs or other VTs that were not induced at the first procedure.
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Michifumi
authors.initials: M
authors.lastname: Tokuda
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Pipin
authors.initials: P
authors.lastname: Kojodjojo
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Tung
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Inada
authors.affiliation: Division of Cardiology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Matsuo
authors.affiliation: Division of Cardiology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Teiichi
authors.initials: T
authors.lastname: Yamane
authors.affiliation: Division of Cardiology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Yoshimura
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Usha B
authors.initials: UB
authors.lastname: Tedrow
authors.affiliation: Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
mesh_terms: D000200:Action Potentials; D000368:Aged; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects; D016009:Chi-Square Distribution; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012086:Reoperation; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome
keywords: catheter ablation; electrocardiogram; outcome; repeat procedure; ventricular tachycardia