title: Catheter ablation of multiple ventricular tachycardias after myocardial infarction guided by combined contact and noncontact mapping.
abstract: BACKGROUND
  Insights gained from noncontact mapping of ventricular tachycardia (VT) have not been systematically applied to contact maps. This study sought to unify both techniques for an individualized approach to the patient with multiple ischemic VTs irrespective of cycle length.
  
  
  RESULTS
  For 12 consecutive patients with chronic myocardial infarction and recurrent VT, bipolar contact maps were acquired during sinus or paced rhythm. Additional noncontact maps were obtained during 48 induced VTs (cycle length 192 to 579 ms). Endocardial exit sites were superimposed on contact maps and verified by pace-mapping. Radiofrequency lesions were extended for critical borders defined by multiple neighboring exits and followed the isovoltage contour line of contact maps. Nine critical borders were identified in 8 patients and constituted the substrate for 31 VTs. The voltage at exit sites was 0.8 mV (range 0.1 to 2.3). Noncontact maps revealed 23+/-18% of isthmus conduction. Thirty-seven (77%) of all and 83% of clinically documented VTs were rendered noninducible irrespective of cycle length by application of 27 radiofrequency lesions (range 18 to 56). Spontaneous transitions between distinct VTs along critical borders were demonstrated in 4 patients. Pace-mapping reproduced the QRS morphology of 81% of VTs and was associated with successful ablation (P<0.01). Noninducibility of any sustained VT was reached for 8 (67%) patients. During 15 months (range 5 to 28) of follow-up, 8 patients remained without recurrence, and VT episodes were reduced in the other 4 patients (P<0.01). VT cycle length was not predictive for acute or long-term success.
  
  
  CONCLUSIONS
  The combined approach of contact and noncontact mapping effectively defines critical borders as the substrate of multiple VTs without limitation for unstable VTs.
authors.affiliation: Department of Cardiology, University Heart Center Hamburg, Martinistrasse 52, 20246 Hamburg, Germany. h.klemm@uke.uni-hamburg.de
authors.forename: Hanno U
authors.initials: HU
authors.lastname: Klemm
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ventura
authors.forename: Daniel
authors.initials: D
authors.lastname: Steven
authors.forename: Christin
authors.initials: C
authors.lastname: Johnsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Rostock
authors.forename: Boris
authors.initials: B
authors.lastname: Lutomsky
authors.forename: Tim
authors.initials: T
authors.lastname: Risius
authors.forename: Thomas
authors.initials: T
authors.lastname: Meinertz
authors.forename: Stephan
authors.initials: S
authors.lastname: Willems
mesh_terms: D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000628:therapy*; D016896:Treatment Outcome