title: Lessons from dissociated pulmonary vein potentials: entry block implies exit block.
abstract: OBJECTIVE
  Prior reports using pacing manoeuvres, demonstrated an up to 42% prevalence of residual pulmonary vein to left atrium (PV-LA) exit conduction after apparent LA-PV entry block. We aimed to determine in a two-centre study the prevalence of residual PV-LA exit conduction in the presence of unambiguously proven entry block and without pacing manoeuvres.
  
  
  RESULTS
  Of 378 patients, 132 (35%) exhibited spontaneous pulmonary vein (PV) potentials following circumferential PV isolation guided by three-dimensional mapping and a circular mapping catheter. Pulmonary vein automaticity was regarded as unambiguous proof of LA-PV entry block. We determined the prevalence of spontaneous exit conduction of the spontaneous PV potentials toward the LA. Pulmonary vein automaticity was observed in 171 PVs: 61 right superior PV, 33 right inferior PV, 47 left superior PV, and 30 left inferior PV. Cycle length of the PV automaticity was >1000 ms in all cases. Spontaneous PV-LA exit conduction was observed in one of 171 PVs (0.6%). In a subset of 69 PVs, pacing from within the PV invariably confirmed PVLA exit block.
  
  
  CONCLUSIONS
  Unidirectional block at the LA-PV junction is unusual (0.6%). This observation is supportive of LA-PV entry block as a sufficient electrophysiological endpoint for PV isolation.
authors.affiliation: Department of Cardiology, St Jan Hospital Bruges, Ruddershove 10, 8000 Bruges, Belgium. mattias.duytschaever@azbrugge.be
authors.forename: Mattias
authors.initials: M
authors.lastname: Duytschaever
authors.forename: Grim
authors.initials: G
authors.lastname: De Meyer
authors.forename: Marta
authors.initials: M
authors.lastname: Acena
authors.forename: Milad
authors.initials: M
authors.lastname: El-Haddad
authors.forename: Yves
authors.initials: Y
authors.lastname: De Greef
authors.forename: Frederic
authors.initials: F
authors.lastname: Van Heuverswyn
authors.forename: Yves
authors.initials: Y
authors.lastname: Vandekerckhove
authors.forename: Rene
authors.initials: R
authors.lastname: Tavernier
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lee
authors.forename: Peter
authors.initials: P
authors.lastname: Kistler
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D001530:Belgium / Q000453:epidemiology; D018780:Body Surface Potential Mapping / Q000706:statistics & numerical data; D002304:Cardiac Pacing, Artificial / Q000379:methods / Q000706:statistics & numerical data*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D006327:Heart Block / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011667:Pulmonary Veins / Q000601:surgery*; D018570:Risk Assessment; D025321:Surgery, Computer-Assisted / Q000706:statistics & numerical data; D016896:Treatment Outcome