title: Atrial signal analysis and defibrillation threshold assessment in chronic persistent and reinduced atrial fibrillation.
abstract: BACKGROUND
  Induced versus spontaneous atrial fibrillation (AF) is of interest for assessing atrial defibrillation threshold reproducibility.
  
  
  RESULTS
  Twenty-one patients with chronic AF underwent internal cardioversion with assessment of atrial defibrillation threshold at baseline and at reinduced AF. High right atrial (HRA) and coronary sinus (CS) bipolar recordings were analyzed to measure the mean local atrial period, its coefficient of variation, the 5th (P5) and 95th (P95) percentiles of atrial intervals, and the percentage of points lying at the baseline (number of occurrences), and to quantify AF organization. Atrial defibrillation threshold was comparable in baseline and reinduced AF in terms of leading-edge voltage and delivered energy. Baseline and reinduced AF were comparable with regard to overall signal parameters (both in HRA and CS) and the presence of an organized arrhythmia pattern. As for individual variables, P5 increased while P95 and coefficient of variation decreased in reinduced AF compared with spontaneous AF (statistical significance was achieved for all these parameters in HRA, but only for coefficient of variation and P95 in CS).
  
  
  CONCLUSIONS
  Sustained AF reinduced after cardioversion of chronic AF is comparable with baseline AF in terms of atrial defibrillation threshold, atrial cycle length, and pattern of organization. Therefore, a clinical model based on reinduction of sustained AF after cardioversion is suitable for studying the effects of a series of interventions on atrial defibrillation threshold. However, because this model does not yield a form of AF with comparable indices of local refractoriness (e.g., P5), it is not recommended when analyzing local electrophysiologic properties.
authors.affiliation: Institute of Cardiology, University of Bologna, Azienda Ospedaliera S. Orsola-Malpighi, Italy. cardio1@almadns.unibo.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.forename: Pietro
authors.initials: P
authors.lastname: Bartolini
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Calcagnini
authors.forename: Claudia
authors.initials: C
authors.lastname: Camanini
authors.forename: Ivan
authors.initials: I
authors.lastname: Corazza
authors.forename: Romano
authors.initials: R
authors.lastname: Zannoli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barbaro
authors.forename: Angelo
authors.initials: A
authors.lastname: Branzi
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000628:therapy*; D016275:Atrial Function; D002908:Chronic Disease; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric