title: High-density mapping of atrial fibrillation in a chronic substrate: evidence for distinct modes of repetitive wavefront propagation.
abstract: BACKGROUND
  Temporal dynamics of electrical wave propagation during AF is unknown. There are reports of transient linking of atrial activation. We aim to characterize temporal dynamics of wave propagation patterns during AF in an established chronically remodeled substrate.
  
  
  METHODS
  Bi-atrial epicardial mapping of AF (mean duration 62±61s) was performed in 13 sheep with induced hypertension using custom-designed plaques. Wave propagation patterns were classified into periods of repetitive activity termed modes.
  
  
  RESULTS
  In total, we identified 9241 distinct depolarization events which were classified as: passing wave (69% occurrence, 68.6% of total time), point source (20.4%, 13.1%), wave collision (4%, 2.8%), re-entrant wave (0.7%, 6.3%), half-rotation (2.9%, 4.4%), wave splitting (2.7%, 4.3%), conduction block (0.05%, 0.03%) and figure of eight reentry (0.05%, 0.05%). Episodes of re-entrant activity had mean length 701±1012ms. A total of 435 modes of distinct periods of repetitive activity were detected (121 in LA and 314 in RA). Looking at temporal changes between modes, we found a preferential transition: change between train of waves propagating from direction of coronary sinus and reentrant activity. High density mapping of the hypertensive fibrillating atria observed 20% point sources and 0.7% of reentrant activation which may have served as drivers of AF. Remaining activations were peripheral waves. Majority of the activation was organized into events of transient linking with existence of preferential types of transitions.
  
  
  CONCLUSIONS
  These findings support the importance of substrate based regions of anatomically or functionally determined preferential conduction in the maintenance of AF.
authors.affiliation: Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia; Department of Cardiology, University Hospital Eppendorf, Hamburg, Germany. Electronic address: pawel.kuklik@adelaide.edu.au.
authors.forename: Pawel
authors.initials: P
authors.lastname: Kuklik
authors.affiliation: Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Dennis H
authors.initials: DH
authors.lastname: Lau
authors.affiliation: Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Anand N
authors.initials: AN
authors.lastname: Ganesan
authors.affiliation: Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Brooks
authors.affiliation: Centre for Heart Rhythm Disorders (CHRD), South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide and Royal Adelaide Hospital, Adelaide, Australia.
authors.forename: Prashanthan
authors.initials: P
authors.lastname: Sanders
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology*; D053840:Brugada Syndrome / Q000503:physiopathology*; D000075224:Cardiac Conduction System Disease; D004195:Disease Models, Animal; D056149:Epicardial Mapping / Q000379:methods*; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology; D012756:Sheep
keywords: AF mechanisms; Arrhythmia mapping; Atrial fibrillation; Hypertension