title: Spectral analysis of intracardiac electrograms during induced and spontaneous ventricular fibrillation in humans.
abstract: OBJECTIVE
  Very limited data are available on the differences between spontaneous and induced episodes of ventricular fibrillation (VF) in humans. The aim of the study was to compare the spectral characteristics of the electrical signal recorded by an implantable cardioverter defibrillator (ICD) during both types of episodes.
  
  
  RESULTS
  Thirteen ICD patients with at least one spontaneous and one induced VF recorded by the device were included in the study. A spectral representation was obtained for the first 3 s of the intracardiac unipolar electrogram during VF. The dominant frequency (f(d)), the peak power at f(d), an organization index (OI), a bandwidth measurement, and an estimate of the correlation with a sinusoidal wave (leakage) were estimated for each episode. The f(d) was higher in induced episodes (4.75 +/- 0.57 vs. 3.95 +/- 0.59 Hz for the spontaneous episodes, P = 0.002), as well as the degree of organization assessed by the OI, bandwidth, and leakage parameters.
  
  
  CONCLUSIONS
  Clinical and induced VF episodes in humans have different spectral characteristics. Changes in the electrophysiological substrate or in the location of the arrhythmia wavefront at onset could play a role to explain the observed differences.
authors.affiliation: Arrhythmia Unit, Hospital Universitario Virgen de la Arrixaca de Murcia, El Palmar, Murcia 30120, Spain. jjsanchezmunoz@gmail.com
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Sánchez-Muñoz
authors.forename: José Luis
authors.initials: JL
authors.lastname: Rojo-Alvarez
authors.forename: Arcadi
authors.initials: A
authors.lastname: García-Alberola
authors.forename: Estrella
authors.initials: E
authors.lastname: Everss
authors.forename: Felipe
authors.initials: F
authors.lastname: Alonso-Atienza
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ortiz
authors.forename: Juan
authors.initials: J
authors.lastname: Martínez-Sánchez
authors.forename: Javier
authors.initials: J
authors.lastname: Ramos-López
authors.forename: Mariano
authors.initials: M
authors.lastname: Valdés-Chavarri
mesh_terms: D017147:Defibrillators, Implantable; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014693:Ventricular Fibrillation / Q000175:diagnosis*