title: Long-term follow-up of changes in fibrillation waves in patients with persistent atrial fibrillation: spectral analysis of surface ECG.
abstract: BACKGROUND
  Little is known about the shortening of atrial refractoriness as a result of electrical remodeling in atrial fibrillation (AF) in clinical cases, especially in terms of long-term follow-up, because of a lack of noninvasive testing methods.
  
  
  RESULTS
  The present study population comprised 38 consecutive patients with persistent AF (PAF, >1 month). Before and after the follow-up period of 1-14 months, surface ECGs were recorded for analysis. In each case, the fibrillation wave was purified by subtracting the QRS-T complex template and then power spectral analysis was performed. The mean fibrillation cycle length (FCL) and FCL coefficient of variation (FCL-CV) were determined from peak power frequency in 20 epochs in each recording. The change in FCL (FCL) was calculated by subtracting the baseline FCL from the FCL after the follow-up period. To correct for the difference in the follow-up period, DeltaFCL was divided by the follow-up period in each case. In 38 cases, mean FCL decreased from 160+/-20 ms to 151+/-19 ms (p<0.05), and the FCL-CV also decreased from 15+/-9% to 12+/-5% (p<0.05). The corrected DeltaFCL was -2.4+/-7.6 (ms/month) and there was a significant negative correlation between corrected DeltaFCL and baseline FCL (p<0.01).
  
  
  CONCLUSIONS
  Shortening of the FCL during a relatively long-term follow-up period was observed in patients with PAF.
authors.affiliation: Department of Internal Medicine/Cardiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara 228-8555, Japan. sasatake@med.kitasato-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Shinichi
authors.initials: S
authors.lastname: Niwano
authors.forename: Sae
authors.initials: S
authors.lastname: Sasaki
authors.forename: Ryuta
authors.initials: R
authors.lastname: Imaki
authors.forename: Masaru
authors.initials: M
authors.lastname: Yuge
authors.forename: Shoji
authors.initials: S
authors.lastname: Hirasawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Satoh
authors.forename: Masahiko
authors.initials: M
authors.lastname: Moriguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Fujiki
authors.forename: Tohru
authors.initials: T
authors.lastname: Izumi
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male