title: The influence of cavotricuspid isthmus length on total radiofrequency energy to cure right atrial flutter.
abstract: OBJECTIVE
  The complexity and success rate of right atrial flutter ablation is highly dependent on anatomical structures.
  
  
  METHODS
  The study comprised 35 consecutive patients (33-77 years old; 30 men) who underwent ablation of typical atrial flutter. The linear ablation line was measured offline as a surrogate for the cavotricuspid isthmus (CTI) length with the help of a three-dimensional mapping and navigation system (Ensite™). Biophysical parameters, such as total radiofrequency (RF) energy and time of the ablation procedure, were analysed to test the hypothesis that any of these variables show a correlation with the length of the ablation line.
  
  
  RESULTS
  Bidirectional isthmus block was achieved in all cases. The isthmus length had a mean value of 32 ± 12 mm with a range of 14-57 mm. The linear regression between the CTI length and the total RF energy was not significant. There was no significant difference in energy (32.281 ± 25.587 vs. 37.136 ± 24.250 W-s, p = NS) or in the total ablation time (759 ± 646 vs. 802 ± 533 s, p = NS) between the group with short (< 29 mm; n = 17) vs. long CTI (≥ 29 mm, n = 18). When comparing different ablation technologies, total RF energy delivered with 8-mm catheter technology (group I) was significantly lower than in patients with cross over from 8-mm to cooled ablation technology (group III) (29.615 ± 12.331 vs. 62.674 ± 28.735 W-s, p = 0.01). The same was true for the comparison between cooled ablation technology (group II) and group III (19.879 ± 13.669 vs. 62.674 ± 28.735 W-s, p = 0.002).
  
  
  CONCLUSIONS
  The length of the CTI as measured with help of a three-dimensional mapping system may reflect only a weak indicator for the complexity of flutter ablation procedures. The thickness of musculature and specific anatomy of the CTI seem to be the main challenges in performing a linear ablation to achieve bidirectional block.
authors: Department of Cardiology, Salzburger Landeskliniken, Paracelsus Medical University, Austria. c.schernthaner@salk.at.
authors: Christiana
authors: C
authors: Schernthaner
authors: Bettina
authors: B
authors: Haidinger
authors: Mathias Christoph
authors: MC
authors: Brandt
authors: Johannes
authors: J
authors: Kraus
authors: Franz
authors: F
authors: Danmayr
authors: Uta C
authors: UC
authors: Hoppe
authors: Bernhard
authors: B
authors: Strohmer
mesh_terms: D000328:Adult; D000368:Aged; D063405:Anatomic Variation; D001282:Atrial Flutter / Q000473:pathology* / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: atrial flutter; cavotricuspid isthmus; radiofrequency catheter ablation