title: Spatial and temporal stability of complex fractionated electrograms in patients with persistent atrial fibrillation over longer time periods: relationship to local electrogram cycle length.
abstract: BACKGROUND
  Atrial fibrillation (AF) ablation guided by complex fractionated electrograms (CFE) has been described, but the spatial and temporal stability of the electrograms (EGMs) has been questioned.
  
  
  OBJECTIVE
  The purpose of this study was to prospectively assess the spatial and temporal stability of CFE in patients with persistent AF.
  
  
  METHODS
  Twenty-four patients were studied. For 12 patients, two high-density CFE maps were performed during AF at baseline (0 minute) and 20 minutes later using the EnSite NavX system. Six-second bipolar EGMs were collected throughout the left atrium (LA) using a circular mapping catheter. Automated software measured the time between discrete local EGM deflections yielding a mean local cycle length (CL). EGMs with mean CL <120 ms were considered CFE. The LA was divided into six regions. Spatial distribution of EGMs at 0 and 20 minutes was compared in each region across three different CL ranges (A = 50-120 ms, B = 121-200 ms, C = 200-500 ms). The 0- and 20-minute CFE maps were directly superimposed offline in MATLAB, and the mean CL value for each point that was sampled in both maps was compared in each CL range (A-C). For the other 12 patients, repetitive measurements (1-minute intervals for 5 minutes) of mean CL were obtained at a sample point for each CL range (A-C) in each patient and compared for consistency.
  
  
  RESULTS
  A total of 324 +/- 65 points were collected per map. Globally in the LA, the distribution of CLs did not change from 0 to 20 minutes (A: 47.1% vs 45.0%; B: 35.3% vs 36.5%; C: 16.0% vs 16.9%; P = .6). The CL distribution in each of the six regions of the LA also did not change significantly from 0 to 20 minutes. There was no significant change in repetitive CL measures for range A (mean DeltaCL 12 +/- 4 ms, P = .4). However, there was significant variation over 5 minutes for ranges B and C (mean DeltaCL 39 +/- 19 ms and 48 +/- 22 ms, respectively, P <.05 for both). Superimposing maps showed 74.7% point-to-point match for range A, 39.3% for range B, and 14.2% for range C (within 30 ms), with a significant correlation seen only for range A (r = 0.82, P <.001).
  
  
  CONCLUSIONS
  CFE show a high degree of spatial and temporal stability. Greater temporal variation is seen in progressively longer CL regions that are outside of the CFE region of interest.
authors.affiliation: Southlake Regional Health Centre, Newmarket, Ontario, Canada. atul.verma@utoronto.ca
authors.forename: Atul
authors.initials: A
authors.lastname: Verma
authors.forename: Zaev
authors.initials: Z
authors.lastname: Wulffhart
authors.forename: Marianne
authors.initials: M
authors.lastname: Beardsall
authors.forename: Bonnie
authors.initials: B
authors.lastname: Whaley
authors.forename: Carol
authors.initials: C
authors.lastname: Hill
authors.forename: Yaariv
authors.initials: Y
authors.lastname: Khaykin
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D018780:Body Surface Potential Mapping / Q000295:instrumentation / Q000379:methods*; D017115:Catheter Ablation; D004452:Echocardiography; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008564:Membrane Potentials; D008875:Middle Aged; D011446:Prospective Studies; D013318:Stroke Volume; D013997:Time Factors