Spatial and temporal stability of complex fractionated electrograms in patients with persistent atrial fibrillation over longer time periods: relationship to local electrogram cycle length.

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).

Conclusion: 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.