title: Three-dimensional dominant frequency mapping using autoregressive spectral analysis of atrial electrograms of patients in persistent atrial fibrillation.
abstract: BACKGROUND
  Areas with high frequency activity within the atrium are thought to be 'drivers' of the rhythm in patients with atrial fibrillation (AF) and ablation of these areas seems to be an effective therapy in eliminating DF gradient and restoring sinus rhythm. Clinical groups have applied the traditional FFT-based approach to generate the three-dimensional dominant frequency (3D DF) maps during electrophysiology (EP) procedures but literature is restricted on using alternative spectral estimation techniques that can have a better frequency resolution that FFT-based spectral estimation.
  
  
  METHODS
  Autoregressive (AR) model-based spectral estimation techniques, with emphasis on selection of appropriate sampling rate and AR model order, were implemented to generate high-density 3D DF maps of atrial electrograms (AEGs) in persistent atrial fibrillation (persAF). For each patient, 2048 simultaneous AEGs were recorded for 20.478 s-long segments in the left atrium (LA) and exported for analysis, together with their anatomical locations. After the DFs were identified using AR-based spectral estimation, they were colour coded to produce sequential 3D DF maps. These maps were systematically compared with maps found using the Fourier-based approach.
  
  
  RESULTS
  3D DF maps can be obtained using AR-based spectral estimation after AEGs downsampling (DS) and the resulting maps are very similar to those obtained using FFT-based spectral estimation (mean 90.23 %). There were no significant differences between AR techniques (p = 0.62). The processing time for AR-based approach was considerably shorter (from 5.44 to 5.05 s) when lower sampling frequencies and model order values were used. Higher levels of DS presented higher rates of DF agreement (sampling frequency of 37.5 Hz).
  
  
  CONCLUSIONS
  We have demonstrated the feasibility of using AR spectral estimation methods for producing 3D DF maps and characterised their differences to the maps produced using the FFT technique, offering an alternative approach for 3D DF computation in human persAF studies.
authors.affiliation: Biomedical Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Bloco Delta, Sala 335 - Rua Arcturus, 03 - Jardim Antares, São Bernardo do Campo, SP, CEP 09606-070, Brazil. joao.salinet@ufabc.edu.br.|Department of Engineering, University of Leicester, Leicester, UK. joao.salinet@ufabc.edu.br.
authors.forename: João L
authors.initials: JL
authors.lastname: Salinet
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK. nm180@le.ac.uk.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Masca
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK. peter.stafford@uhl-tr.nhs.uk.|Leicester NIHR Biomedical Research Unit in Cardiovascular Disease, Glenfield Hospital, Leicester, UK. peter.stafford@uhl-tr.nhs.uk.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stafford
authors.affiliation: Department of Cardiovascular Sciences, University of Leicester, Glenfield Hospital, Leicester, UK. gan1@le.ac.uk.|Leicester NIHR Biomedical Research Unit in Cardiovascular Disease, Glenfield Hospital, Leicester, UK. gan1@le.ac.uk.
authors.forename: G André
authors.initials: GA
authors.lastname: Ng
authors.affiliation: Department of Engineering, University of Leicester, Leicester, UK. fss1@le.ac.uk.|Leicester NIHR Biomedical Research Unit in Cardiovascular Disease, Glenfield Hospital, Leicester, UK. fss1@le.ac.uk.
authors.forename: Fernando S
authors.initials: FS
authors.lastname: Schlindwein
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic / Q000379:methods*