title: Isolated potentials and pace-mapping as guides for ablation of ventricular tachycardia in various types of nonischemic cardiomyopathy.
abstract: BACKGROUND
  In patients with prior infarction, isolated potentials (IPs) during sinus rhythm reflect fixed scar and often indicate sites critical for ventricular tachycardia (VT). The purpose of this study was to determine the value of IPs in conjunction with pace-mapping to guide VT ablation in patients with various types of nonischemic cardiomyopathy.
  
  
  METHODS
  Mapping and ablation of VT were performed in 35 consecutive patients (26 men, age 55 ± 13 years, ejection fraction 0.31 ± 0.14) with VT and various etiologies of nonischemic cardiomyopathy. Pace-mapping was performed at sites with low voltage. Radiofrequency energy was delivered at sites with concealed entrainment or matching pace-maps.
  
  
  RESULTS
  One hundred ninety-five VTs (mean cycle length 363 ± 88 ms) were induced. Sites with prespecified ablation criteria displaying IPs during sinus rhythm were recorded in 21 of 35 patients (60%, IP-positive). In these patients, a total of 216 sites meeting prespecified ablation criteria were identified and 146 of 216 sites (68%) displayed IPs. Fifteen of 21 IP-positive patients (71%) no longer had inducible VT after ablation. In 14 of 35 patients, no sites with IPs where prespecified ablation criteria were met were identified (IP-negative) despite combined endocardial and epicardial mapping in 7 of 14 patients. Only 1 of 14 IP-negative patients (7%) no longer had inducible VT at the end of the ablation procedure. During a mean follow-up of 18 ± 13 months, 14 of 21 IP-positive patients (67%) remained arrhythmia-free, compared to 1 of 14 IP-negative patients (7%; P < 0.01). Half of the IP-negative patients had major adverse events due to recurrent arrhythmias, compared to none in IP-positive patients.
  
  
  CONCLUSIONS
  IPs in conjunction with pace-mapping are helpful for identifying critical isthmus areas for ablation of VT in patients with various types of nonischemic cardiomyopathy. Patients with nonischemic cardiomyopathy in whom the arrhythmogenic substrate is characterized by IPs have a more favorable outcome than patients in whom IPs are absent.
authors.affiliation: University of Michigan Medical Center, Ann Arbor, Michigan, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Kühne
authors.forename: Gerald
authors.initials: G
authors.lastname: Abrams
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Sarrazin
authors.forename: Thomas
authors.initials: T
authors.lastname: Crawford
authors.forename: Eric
authors.initials: E
authors.lastname: Good
authors.forename: Aman
authors.initials: A
authors.lastname: Chugh
authors.forename: Matthew
authors.initials: M
authors.lastname: Ebinger
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
authors.forename: Frank
authors.initials: F
authors.lastname: Pelosi
authors.forename: Hakan
authors.initials: H
authors.lastname: Oral
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
authors.forename: Frank M
authors.initials: FM
authors.lastname: Bogun
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D009202:Cardiomyopathies / Q000150:complications* / Q000503:physiopathology; D017115:Catheter Ablation; D016009:Chi-Square Distribution; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008824:Michigan; D008875:Middle Aged; D011237:Predictive Value of Tests; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome