title: Analysis during sinus rhythm and ventricular pacing of reentry circuit isthmus sites in right ventricular cardiomyopathy.
abstract: BACKGROUND
  The entrainment mapping algorithm is used for ablation of ventricular tachycardia (VT) in right ventricular (RV) cardiomyopathy, but ablation at endocardial isthmus sites has only a moderate success rate. This study was performed to identify additional local electrogram characteristics associated with successful ablation.
  
  
  METHODS
  Using entrainment mapping, 45 reentry circuit isthmus sites were detected in 11 patients with RV cardiomyopathy presenting with 13 monomorphic VTs. Local bipolar electrograms were retrospectively analyzed at reentry circuit isthmus sites during VT, sinus rhythm, and programmed stimulation from the right ventricular apex (RVA), and compared between successful and unsuccessful ablation sites.
  
  
  RESULTS
  Ablation was successful at 10 reentry circuit isthmus sites and unsuccessful at 35 isthmus sites. During VT, a longer endocardial activation time relative to QRS onset, an increased electrogram-QRS interval as a percentage of VT cycle length, and a longer electrogram duration were found at successful in comparison to unsuccessful ablation sites. The presence of isolated diastolic potentials during sinus rhythm at reentry circuit isthmus sites, consistent with slow conduction or unidirectional conduction block, was associated with successful catheter ablation. Prolongation of the duration of the local multipotential electrogram by >100 ms during programmed RVA pacing at reentry circuit exit sites, indicating functional conduction disorder was also a marker of successful ablation.
  
  
  CONCLUSIONS
  The demonstration of multipotential electrogram characteristics indicating fixed or functional conduction block may increase the likelihood of successful VT ablation at exit and central isthmus sites of reentry circuits in RV cardiomyopathy.
authors.affiliation: Medizinische Klinik I, Klinikum Grosshadern, Universität, München, Germany, Muenchen, Germany. Christopher.Reithmann@med.uni-muenchen.de
authors.forename: Christopher
authors.initials: C
authors.lastname: Reithmann
authors.forename: Michael
authors.initials: M
authors.lastname: Ulbrich
authors.forename: Anton
authors.initials: A
authors.lastname: Hahnefeld
authors.forename: Armin
authors.initials: A
authors.lastname: Huber
authors.forename: Tomas
authors.initials: T
authors.lastname: Matis
authors.forename: Gerhard
authors.initials: G
authors.lastname: Steinbeck
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000175:diagnosis* / Q000601:surgery*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome