title: Low clinical recurrence and procedure benefits following treatment of common atrial flutter by electrogram-guided hot spot focal cryoablation.
abstract: BACKGROUND
  The study sought to evaluate whether electrogram-aided identification of hot spot targets produces additional clinical and/or procedure benefits when using a non-traditional focal cryo ablation method to treat common atrial flutter.
  
  
  METHODS
  A preliminary study identified a specific electrogram criterion (e.g., a stimulus to onset of electrogram time of 74 [+/- 5] ms) that produced successful cryo testing plus subsequent cryoablation with demonstrable bi-directional isthmus block created at intervention site. In the present study, 26 consecutive patients with symptomatic common atrial flutter were ablated with a 9FR 8 mm tip cryo catheter using electrogram-aided identification of hot spot targets with a stimulus to onset of electrogram time of > or =70 ms. Outcomes measured were bi-directional isthmus block at intervention, symptom and conduction recurrence at 3 month follow-up, symptom recurrence at 6 month follow-up, and procedure characteristics.
  
  
  RESULTS
  Acute success rate at intervention was 100%. The percentage of patients with symptom recurrence by 3 month follow-up was 4.5% and no additional patients had arrhythmia symptoms documented by 12 month follow-up. Repeat electrophysiological study (EPS) at 3 month follow-up identified 44% of patients with conduction recurrence. The mean +/- SD number of cryo tests and ablations were 11 +/- 9 and 2 +/- 1, respectively. Procedure, fluoroscopy and cryoapplication times were 77 +/- 29 min, 11 +/- 7 min, and 28 +/- 11 min, respectively.
  
  
  CONCLUSIONS
  A high acute success rate, plus low long-term clinical recurrence rate and procedure benefits may be achieved with electrogram-aided identification of hot spots for focal cryo ablation treatment of common atrial flutter using a 9FR 8 mm tip cryo catheter. The population of patients who were asymptomatic and had demonstrated conduction recurrence on repeat EPS at 3 month follow-up require close scrutiny over the long-term to ascertain whether they eventually experience arrhythmic symptoms. However, should these patients remain symptom-free over the long-term it would suggest that the entire isthmus may not be needed to support symptomatic common atrial flutter.
authors.affiliation: Cardiology Department and Arrhythmia Center of Policlinico MultiMedica, Sesto S Giovanni, Milan, Italy. montenero@hotmail.com
authors.forename: Annibale S
authors.initials: AS
authors.lastname: Montenero
authors.forename: Nicola
authors.initials: N
authors.lastname: Bruno
authors.forename: Andrea
authors.initials: A
authors.lastname: Antonelli
authors.forename: Daniele
authors.initials: D
authors.lastname: Mangiameli
authors.forename: Luca
authors.initials: L
authors.lastname: Barbieri
authors.forename: Francesco
authors.initials: F
authors.lastname: Zumbo
authors.forename: Peter
authors.initials: P
authors.lastname: Andrew
mesh_terms: D001282:Atrial Flutter / Q000175:diagnosis / Q000601:surgery*; D003452:Cryosurgery / Q000295:instrumentation / Q000379:methods*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D012008:Recurrence; D018709:Statistics, Nonparametric; D016896:Treatment Outcome