title: Initial results of linear duty-cycled radiofrequency for atypical flutter and atrial tachycardia.
abstract: BACKGROUND
  Duty-cycled radiofrequency (DCRF) is increasingly used for ablation of atrial fibrillation (AF). Many patients also have atrial flutter (AFL). Recently, a linear multielectrode has been shown to create linear block at the cavotricuspid isthmus and in the left atrium (LA).
  
  
  OBJECTIVE
  To map and ablate atypical AFL and atrial tachycardias (ATs) in the right and LA using a linear multielectrode with DCRF.
  
  
  METHODS
  The linear multielectrode delivers DCRF at 20-45 W maximum in 1:1 unipolar/bipolar temperature-controlled mode. Target temperatures were manually titrated to 60 °C in the LA, if power >5W indicated adequate passive cooling.
  
  
  RESULTS
  A total of 76 AT/AFL were targeted in 57 patients. Acute success was reached in 14/15 (93%) right AT, in 17/22 (77%) left atrial roof AFL, in 5/6 (83%) septal AFL, in 9/9 (100%) other left atrial AT, but only in 8/23 (35%) AFL from the mitral isthmus (which rose to 13/23 [57%] with additional use of irrigated radiofrequency). Nevertheless, freedom of AF/AFL 10 ± 6 months after a single procedure was documented in 92% of right AT, 71% of roof AFL, 73% for mitral AFL, and 60% of septal or other LA AT/AFL. No char formation was noted. However, frequent induction of AF and one case of asystole occurred during delivery of DCRF in a pacemaker patient.
  
  
  CONCLUSIONS
  The linear multielectrode allows mapping and ablation of atypical AFL/AT. Freedom of AF/AT was reached in 60%-92% depending on localization and number of arrhythmias. Technical modifications will improve safety and efficacy.
authors.affiliation: Cardiovascular Center, Clinic im Park, Zurich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Naegeli
authors.forename: Lam
authors.initials: L
authors.lastname: Dang
authors.forename: Stefanie
authors.initials: S
authors.lastname: Boll
authors.forename: Christine
authors.initials: C
authors.lastname: Tivig
authors.forename: Christoph
authors.initials: C
authors.lastname: Scharf
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013612:Tachycardia, Ectopic Atrial / Q000601:surgery*; D016896:Treatment Outcome