title: High-density epicardial mapping of the pulmonary vein-left atrial junction in humans: insights into mechanisms of pulmonary vein arrhythmogenesis.
abstract: BACKGROUND
  The pulmonary veins (PVs) and the PV-LA (left atrium) junction are established sources of triggers initiating atrial fibrillation. In addition, they have been implicated in the maintenance of arrhythmia.
  
  
  OBJECTIVE
  To undertake high-density electrophysiological characterization of the right superior PV-LA junction in humans.
  
  
  METHODS
  Mapping was performed in 18 patients without a history of atrial fibrillation undergoing cardiac surgery. A high-density epicardial plaque was positioned at the anterior right superior pulmonary vein covering 3 regions: LA, PV-LA junction, and the PV. Isochronal maps were created during (1) sinus rhythm (SR); (2) LA pacing (LA-Pace); (3) PV pacing (PV-Pace); (4) LA programmed electrical stimulation (LA-PES); and (5) PV programmed electrical stimulation (PV-PES). Regional differences in conduction slowing/conduction block (CS/CB) and the prevalence of fractionated signals (FS) and double potentials (DPs) were assessed.
  
  
  RESULTS
  A region of isochronal crowding representing CS/CB developed at the PV-LA junction in 84% of the maps. Three distinct activation patterns were seen. Pattern 1: Uniform SR activation without CS/CB. LA-Pace and PES caused 1 to 2 lines of isochronal crowding (CS/CB) at the PV-LA junction. Pattern 2: CS/CB occurred at the PV-LA junction in SR. LA/PV-Pace and LA/PV-PES caused an increase in CS/CB at the PV-LA junction with widely split DPs and FS. Pattern 3: A single incomplete line of CS at the PV-LA junction in SR. With LA/PV pacing and LA/PV-PES, multiple lines (≥3) of CS/CB developed at the PV-LA junction with evidence of circuitous activation and a marked increase in DPs and FS.
  
  
  CONCLUSIONS
  High-density epicardial mapping of the right superior pulmonary vein demonstrates marked functional conduction delay and circuitous activation patterns at the PV-LA junction, creating the substrate for reentry.
authors: Department of Cardiology, The Royal Melbourne Hospital, Melbourne, Australia.
authors: Geoffrey
authors: G
authors: Lee
authors: Steven
authors: S
authors: Spence
authors: Andrew
authors: A
authors: Teh
authors: John
authors: J
authors: Goldblatt
authors: Marco
authors: M
authors: Larobina
authors: Victoria
authors: V
authors: Atkinson
authors: Robin
authors: R
authors: Brown
authors: Joseph B
authors: JB
authors: Morton
authors: Prashanthan
authors: P
authors: Sanders
authors: Peter M
authors: PM
authors: Kistler
authors: Jonathan M
authors: JM
authors: Kalman
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000503:physiopathology*; D056149:Epicardial Mapping / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000503:physiopathology*