title: Electrocardiographic characteristics of fibrillatory waves in new-onset atrial fibrillation.
abstract: OBJECTIVE
  In atrial fibrillation (AF), fibrillatory waves of surface electrocardiograms (ECG) vary among patients with respect to waveform and repetition rate. The purpose of this study was to (i) explore clinical determinants of new-onset AF and (ii) determine prognostic significance to predict initial treatment outcome of electrocardiographic fibrillatory wave characteristics in new-onset AF.
  
  
  RESULTS
  Twenty-five patients (15 male, mean age 69 +/- 16 years) with new-onset AF (median AF duration 8 days) were studied. Fibrillatory rate and exponential decay defined as decay of the curve that connects power maxima of dominant and harmonic frequency components were obtained by spatiotemporal QRST cancellation and time-frequency analysis of the index ECG (before treatment initiation). Baseline AF rate was 380 +/- 50 fibrillations per minute (fpm) (range 222-494); patients' age (beta = - 1.747, P = 0.003) and AF duration (beta = 0.726, P = 0.036) were independently related with fibrillatory rate. AF terminated within 24 h in seven patients, while it was persistent in the other 18 patients. Terminating AF had lower atrial rate (333 +/- 66 vs. 398 +/- 40 fpm, P = 0.005) and exponential decay (1.03 +/- 0.36 vs. 1.40 +/- 0.37, P = 0.041) than persisting AF. Multivariate analysis revealed fibrillatory rate to be the only independent predictor of AF termination or persistence (beta = 0.031, P = 0.031). Sensitivity and specificity for predicting AF termination were strongly related to fibrillatory rate (area under the curve = 0.817). Sensitivity and specificity were 89% and 71% for a fibrillatory rate of 355 fpm.
  
  
  CONCLUSIONS
  Fibrillatory rates vary substantially among patients to new-onset AF and are related to patients' age and AF duration. Lower fibrillatory rates indicate higher chances of spontaneous AF termination within 24 h.
authors.affiliation: Department of Cardiology, Good Samaritan Hospital and Harbor-UCLA Medical Center Los Angeles, CA, USA.
authors.forename: Daniela
authors.initials: D
authors.lastname: Husser
authors.forename: David S
authors.initials: DS
authors.lastname: Cannom
authors.forename: Anil K
authors.initials: AK
authors.lastname: Bhandari
authors.forename: Martin
authors.initials: M
authors.lastname: Stridh
authors.forename: Leif
authors.initials: L
authors.lastname: Sörnmo
authors.forename: S Bertil
authors.initials: SB
authors.lastname: Olsson
authors.forename: Andreas
authors.initials: A
authors.lastname: Bollmann
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D012008:Recurrence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity