title: Surface atrial frequency analysis in patients with atrial fibrillation: assessing the effects of linear left atrial ablation.
abstract: BACKGROUND
  Our group has shown previously that measurements of atrial frequency can be obtained from surface 12-lead ECG recordings of patients during atrial fibrillation (AF), using a combination of principal component and Fourier transform algorithms. Such measurements are reproducible over time and change with drug manipulation of the arrhythmia.
  
  
  OBJECTIVE
  To determine whether linear left atrial ablation, using a combination of "roof" and "mitral isthmus" lines results in changes in surface atrial frequency during AF and to assess the contribution of each individual line when sited sequentially.
  
  
  RESULTS
  Computerized recordings from 26 patients, who had undergone linear ablation procedures for AF, were reviewed. The atrial signal was extracted from the 12-lead ECG data by principal component analysis and the main frequency component identified using Fourier analysis. Atrial frequency before and after these two standard ablation lines was compared. Atrial frequency decreased significantly after the combination of roof and mitral isthmus lines (5.66 vs 5.15 Hz) and when either roof (5.61 vs 5.13 Hz) or mitral isthmus (5.89 vs 5.75 Hz) lines were sited first. However, only the roof line led to a significant reduction in atrial frequency when sited second (5.64 vs 5.49 Hz).
  
  
  CONCLUSIONS
  Measurements of atrial frequency can be obtained from surface 12-lead ECG recordings during AF and change as predicted in response to linear left atrial ablation. This technique may be useful in assessing antiarrhythmic treatments for AF.
authors.affiliation: Department of Cardiology, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Trust, UK. D.T. Raine@ncl.ac.uk
authors.forename: Dan
authors.initials: D
authors.lastname: Raine
authors.forename: Philip
authors.initials: P
authors.lastname: Langley
authors.forename: Alan
authors.initials: A
authors.lastname: Murray
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Furniss
authors.forename: John P
authors.initials: JP
authors.lastname: Bourke
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies