title: Identification of successful catheter ablation sites in patients with ventricular tachycardia based on electrogram characteristics during sinus rhythm.
abstract: BACKGROUND
  Zones of slow conduction facilitate reentry, the major mechanism of ventricular tachycardia (VT) after myocardial infarction (MI). Identification of these zones during sinus rhythm (SR) is desirable for radiofrequency (RF) catheter ablation of VT. Local conduction velocity may correlate with electrogram duration.
  
  
  OBJECTIVE
  The purpose of this study was to revise the definition of normal electrogram characteristics and to reevaluate the significance of low-amplitude, long-duration electrograms recorded during SR to select RF catheter ablation sites in patients with VT.
  
  
  METHODS
  Electroanatomic mapping was performed during SR in 10 control patients with normal left ventricles (LVs) and in 10 patients with stable VT after MI. From the controls, reference values for electrogram amplitude, duration (first peak to last peak distance), and fragmentation (positive deflection) were derived. In patients after MI, areas with signals exceeding these values were annotated and related to successful ablation sites.
  
  
  RESULTS
  Ninety-five percent of normal LV electrograms were > or =1.0 mV and < or =28 ms (range 5-39 ms) and all had < or =4 deflections. Based on these results, cutoff values were set at 1 mV, four deflections, and 40 ms. In infarcted hearts, 653 electrograms (44%) were <1.0 mV and of these, 303 were > or =40 ms with >4 deflections and restricted to circumscribed areas. Twenty-seven of 28 targeted VTs remained noninducible after RF catheter ablation within these areas, resulting in 86% sensitivity and 94% specificity for low-amplitude, long-duration electrograms predicting successful ablation sites.
  
  
  CONCLUSIONS
  Identification of successful RF target areas during SR in patients with VT is feasible with high sensitivity and specificity using a mapping strategy based on voltage and duration criteria.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Katja
authors.initials: K
authors.lastname: Zeppenfeld
authors.forename: Philippine
authors.initials: P
authors.lastname: Kiès
authors.forename: Maurits C E F
authors.initials: MC
authors.lastname: Wijffels
authors.forename: Marianne
authors.initials: M
authors.lastname: Bootsma
authors.forename: Lieselot
authors.initials: L
authors.lastname: van Erven
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000009:adverse effects; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology* / Q000601:surgery*; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology; D012107:Research Design; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome