title: Noninvasive assessment of acute changes in atrial electrophysiology after cardioversion by signal-averaged P-wave electrocardiography.
abstract: BACKGROUND
  Atrial remodeling secondary to atrial fibrillation (AF) may be important in the arrhythmogenic process. Unfortunately, the study of electrophysiologic remodeling in humans has been limited by the invasive nature of most tests of electrophysiologic characteristics. We sought to determine whether changes in atrial electrophysiology occur acutely (within the first hour) after cardioversion and whether these changes could be detected noninvasively by measuring the signal-averaged P-wave.
  
  
  METHODS
  The filtered P-wave duration (FPD) was measured by signal-averaged electrocardiography (ECG) at 20 and 60 minutes after cardioversion in 46 patients with AF, and the difference between the two values was calculated. The root-mean-square voltage of the terminal 40 ms of the signal-averaged P-wave at 20 and 60 minutes and the difference between them were also determined.
  
  
  RESULTS
  The FPD at 20 minutes was significantly different from that at 60 minutes (153.0 +/- 19.1 vs 159.7 +/- 24.8 ms; P = 0.02). In a univariate linear regression model, none of the clinical variables studied was significantly associated with the change in FPD. The root-mean-square voltage at 20 minutes was not significantly different from that at 60 minutes (5.8 +/- 3.0 vs 5.5 +/- 2.7; P = 0.14).
  
  
  CONCLUSIONS
  We conclude that significant changes in atrial electrophysiology occur within the first hour after cardioversion of AF. These changes can be detected by measuring the FPD.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Ahmad A
authors.initials: AA
authors.lastname: Elesber
authors.forename: Ana Gabriela
authors.initials: AG
authors.lastname: Rosales
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Malouf
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: Naser M
authors.initials: NM
authors.lastname: Ammash
authors.forename: Krishnaswamy
authors.initials: K
authors.lastname: Chandrasekaran
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Gersh
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hammill
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000628:therapy*; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D013997:Time Factors