title: Non-contact mapping to guide radiofrequency ablation of atypical right atrial flutter.
abstract: OBJECTIVE
  This study was aimed at evaluating the efficacy of non-contact mapping and ablation of non-incisional atypical right atrial (RA) flutters.
  
  
  BACKGROUND
  The majority of atypical RA flutters were reported in patients after surgical incision of the RA.
  
  
  METHODS
  The study group consisted of 15 patients (61 +/- 13 years, 8 males) with atypical atrial flutter (AFL). The RA activation during AFL was delineated using a non-contact mapping system (EnSite 3000 with Precision Software, Endocardial Solutions, St. Paul, Minnesota). The narrowest part of each reentrant circuit was targeted using radiofrequency energy.
  
  
  RESULTS
  In all 15 patients, non-contact mapping showed AFLs confined to the RA with RA activation time accounting for 100% of the cycle length (210 +/- 19 ms). During single-loop re-entry in seven patients, the activation wave front circulated around the central obstacle (CO) in the anterolateral wall with conduction through the channel between the CO and the crista terminalis (CT). During figure-of-eight re-entry in eight patients, simultaneous upper and lower loop re-entry through the conduction gap in the CT was found in four patients, and simultaneous upper loop and free-wall single-loop re-entry was observed in four patients. Radiofrequency ablation of the free-wall channel and/or CT gap was effective in eliminating these AFLs in 13 patients. During a follow-up of 16.8 +/- 3.8 months, two patients had recurrence of left AFL, and one had recurrence of atrial fibrillation.
  
  
  CONCLUSIONS
  Atypical RA flutters could arise from single-loop or double-loop figure-of-eight re-entry. Radiofrequency ablation of the free-wall channel and/or the CT gap was effective in eliminating these arrhythmias.
authors.affiliation: Division of Cardiology, Department of Medicine, National Yang-Ming University School of Medicine, Taipei Veterans General Hospital, Taiwan, Republic of China. ct.tai@msa.hinet.net
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Tai
authors.forename: Tu-Ying
authors.initials: TY
authors.lastname: Liu
authors.forename: Pi-Chang
authors.initials: PC
authors.lastname: Lee
authors.forename: Yenn-Jiang
authors.initials: YJ
authors.lastname: Lin
authors.forename: Mau-Song
authors.initials: MS
authors.lastname: Chang
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged