title: High-resolution signal-averaged analysis of atrial electromagnetic characteristics in patients with paroxysmal lone atrial fibrillation.
abstract: BACKGROUND
  Abnormalities in the electromagnetic signal of the atria during sinus rhythm could serve as markers of triggering foci or substrate for atrial fibrillation (AF). We examined atrial electrophysiologic properties noninvasively by using magnetocardiographic mapping (MCG) in patients with paroxysmal lone AF to find whether any difference exists between those who have frequent triggers of AF and who don't.
  
  
  METHODS
  MCG was recorded over anterior chest during sinus rhythm in 80 patients with paroxysmal lone AF (44 +/- 12 years, 61 males) and 80 matched controls. Atrial wave duration (Pd) and root mean square amplitudes of the last 40 ms (RMS40) of the averaged filtered atrial complex were determined automatically. Patients expressing atrial arrhythmias triggering AF episodes were classified as focal AF.
  
  
  RESULTS
  The Pd was 109 ms in patients and 104 ms in controls (P = 0.007). In focal AF (72%) the Pd was slightly prolonged and its proportion of the PR interval was larger, but RMS40 was normal compared to controls. In other patients, the Pd was close to controls, but the RMS40 was reduced (59 +/- 17 vs74 +/- 36 fT, P = 0.006). Pd and atrial RMS amplitudes were unrelated to duration of AF history or frequency of recurrences.
  
  
  CONCLUSIONS
  Clinical subclasses of lone AF seem to possess distinct signal profiles of atrial depolarization. Differences in electrophysiological properties between these subclasses may reflect pathogenetic variation and could have implications on diagnostics and therapy.
authors.affiliation: Department of Cardiology, Helsinki University Central Hospital, Department of Cardiology, Helsinki, Finland. raija.jurkko@2me.fi
authors.forename: Raija
authors.initials: R
authors.lastname: Jurkko
authors.forename: Heikki
authors.initials: H
authors.lastname: Väänänen
authors.forename: Ville
authors.initials: V
authors.lastname: Mäntynen
authors.forename: Jouni
authors.initials: J
authors.lastname: Kuusisto
authors.forename: Markku
authors.initials: M
authors.lastname: Mäkijärvi
authors.forename: Lauri
authors.initials: L
authors.lastname: Toivonen
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D053798:Magnetocardiography; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted