title: Characteristics of ectopic triggers associated with paroxysmal and persistent atrial fibrillation: evidence for a changing role.
abstract: BACKGROUND
  Atrial premature contractions (APCs) are well described to precede the initiation of paroxysmal atrial fibrillation (pAF). However, whether APC characteristics alter with progression of the arrhythmia is unknown.
  
  
  OBJECTIVE
  To determine the APC characteristics in terms of burden and relative coupling interval with progression of the AF disease process.
  
  
  METHODS
  Fifty consecutive patients with pAF, 50 consecutive patients with persistent AF (perAF), and 25 age-matched controls underwent clinical review, transthoracic echocardiography, and ambulatory electrocardiogram monitoring. After excluding 29 patients who had AF for the entire recording (n = 24) or unreliable recordings (n = 5), we analyzed data from 49 patients with pAF, 24 patients with perAF, and 23 healthy controls. All normal morphology R-R intervals with a >25% decrease in R-R coupling compared with the previous R-R interval (coupling interval index) were deemed APCs (n = 95,873).
  
  
  RESULTS
  The median APC burden was higher in patients with pAF (2 [1-22] APCs/h; P = .004) and perAF (3 [1-6] APCs/h; P = .04) than in controls (1 [0-1] APCs/h) but was not different (P = .66) between the AF subgroups. Patients with pAF had a distinct increase in ectopy burden after 7 PM and elevation throughout the night (P = .002) in comparison with a blunted and complementary temporal response in the perAF cohort (P = .01). Patients with pAF demonstrated a greater proportion of shortly coupled APCs (29% [13-45]; P = .04) compared with persistent arrhythmia (17% [5-29]).
  
  
  CONCLUSIONS
  "Real-life" atrial trigger statistics of APC burden, timing, and diurnal rhythms track the transition from a trigger-based, autonomically sensitive paroxysmal arrhythmia to a more substrate-based persistent disease.
authors.affiliation: Centre for Heart Rhythm Disorders, University of Adelaide, and Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Brooks
authors.forename: Geetanjali
authors.initials: G
authors.lastname: Rangnekar
authors.forename: Anand N
authors.initials: AN
authors.lastname: Ganesan
authors.forename: Ingrid
authors.initials: I
authors.lastname: Salna
authors.forename: Melissa E
authors.initials: ME
authors.lastname: Middeldorp
authors.forename: Pawel
authors.initials: P
authors.lastname: Kuklik
authors.forename: Mathias
authors.initials: M
authors.lastname: Baumert
authors.forename: Kurt C
authors.initials: KC
authors.lastname: Roberts-Thomson
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D018880:Atrial Premature Complexes / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D016022:Case-Control Studies; D018450:Disease Progression; D015716:Electrocardiography, Ambulatory; D005260:Female; D006325:Heart Atria / Q000473:pathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013223:Statistics as Topic; D013995:Time