title: Endocardial mapping of right ventricular outflow tract tachycardia using noncontact activation mapping.
abstract: BACKGROUND
  Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias.
  
  
  RESULTS
  Nine patients with RVOT tachycardia and three patients with ectopic beats were studied using noncontact mapping. A multielectrode array catheter was introduced into the RVOT and tachycardia was analyzed using a virtual geometry. The earliest endocardial activation estimated by virtual electrograms was displayed on an isopotential color map and measured 33 +/- 13 msec before onset of QRS. Virtual unipolar electrograms at this site demonstrated QS morphology. Guided by a locator signal, ablation was performed with a mean of 6.9 +/- 2.2 radiofrequency deliveries. Acute success was achieved in all patients. During follow-up, one patient had a recurrence of RVOT tachycardia. Compared with patients (n = 21) who underwent catheter ablation using a conventional approach, a higher success rate was achieved by noncontact mapping. Procedure time was significantly longer in the noncontact mapping group. Fluoroscopy time was not significantly different in the two groups.
  
  
  CONCLUSIONS
  Noncontact mapping can be used as a reliable tool to identify the site of earliest endocardial activation and to guide the ablation procedure in patients with RVOT tachycardia and in patients with ectopic beats originating from the RVOT.
authors.affiliation: Department of Cardiology and Angiology, University Hospital Münster, Institute for Arteriosclerosis Research at the University of Münster, Münster, Germany. ribbing@uni-muenster.de
authors.forename: Michael
authors.initials: M
authors.lastname: Ribbing
authors.forename: Kristina
authors.initials: K
authors.lastname: Wasmer
authors.forename: Gerold
authors.initials: G
authors.lastname: Mönnig
authors.forename: Paulus
authors.initials: P
authors.lastname: Kirchhof
authors.forename: Peter
authors.initials: P
authors.lastname: Loh
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Haverkamp
authors.forename: Lars
authors.initials: L
authors.lastname: Eckardt
mesh_terms: D000328:Adult; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D004567:Electrodes, Implanted; D022062:Electrophysiologic Techniques, Cardiac; D004699:Endocardium / Q000473:pathology* / Q000601:surgery; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D005858:Germany; D006352:Heart Ventricles / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000601:surgery; D016896:Treatment Outcome; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000601:surgery