title: Analysis of the cardiac rhythm preceding episodes of paroxysmal atrial fibrillation.
abstract: OBJECTIVE
  This study seeks to elucidate whether there was a common mode of initiation of paroxysmal atrial fibrillation (PAF) episodes that might suggest new therapies.
  
  
  METHODS
  A library of 177 digitized and analyzed 24-hour Holter recordings from PAF pharmacotherapy trials was studied. All noise-free PAF episodes > or =0.5 minutes were identified. PAF episodes and the preceding 2 minutes of sinus rhythm were printed as tachograms and visually inspected. Heart rate and ectopic beat behavior were used to characterize modes of PAF onset by comparing half-minute segments of the final 2 minutes of sinus rhythm.
  
  
  RESULTS
  Thirty-four recordings (from 19 patients, aged 61.7 +/- 11.5 years) provided 231 PAF episodes suitable for analysis. No patients had a consistent mode of PAF onset. This was confirmed by systematic analysis of the five patients with the most episodes. Overall, a highly significant increase in ectopic beats, from 1.34 to 6.52 min(-1) (p < 0.001) was found, but heart rate did not significantly change (mean heart rate at onset = 64 beats/min). PAF was initiated by a solitary ectopic beat in more than half of the cases. No consistent evidence for short-long-short sequences, seen in ventricular arrhythmias, was found.
  
  
  CONCLUSIONS
  The mode of onset of atrial fibrillation is inconsistent, both across a population with PAF and within individuals. This has implications for understanding the mechanisms of atrial fibrillation onset in human beings and for the treatment of the disorder.
authors.affiliation: St. Georges Hospital Medical School, London, United Kingdom.
authors.forename: K
authors.initials: K
authors.lastname: Hnatkova
authors.forename: J E
authors.initials: JE
authors.lastname: Waktare
authors.forename: F D
authors.initials: FD
authors.lastname: Murgatroyd
authors.forename: X
authors.initials: X
authors.lastname: Guo
authors.forename: X
authors.initials: X
authors.lastname: Baiyan
authors.forename: A J
authors.initials: AJ
authors.lastname: Camm
authors.forename: M
authors.initials: M
authors.lastname: Malik
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors