title: Computerized high-density mapping of the pulmonary veins: new insights into their electrical activation in patients with atrial fibrillation.
abstract: OBJECTIVE
  To report the method and findings of computerized high-density mapping of pulmonary veins (PVs) in patients undergoing their electrical isolation for atrial fibrillation (AF).
  
  
  RESULTS
  In 17 consecutive patients (8 M, age 55+/-11 years), a 64 electrode basket catheter was placed in the target PVs and 56 bipolar electrograms were recorded, analyzed and isochronal maps were generated. PVs were mapped during sinus rhythm, left-sided pacing and ectopic activity. The sites of earliest activation at the veno-atrial junction were defined as the atrium to vein conduction breakthroughs. PV activation pattern was classified as predominantly longitudinal or transverse, according to the direction of the impulse from the breakthroughs. The ectopic pattern was defined as multifocal, when distant areas in the PV had activation times within 10ms. Thirty-one PVs were mapped. The activation pattern was predominantly longitudinal in 13 PVs and transverse in 18 PVs. Two breakthroughs were identified in 22 PVs and three in nine. All the breakthroughs were evident simultaneously in sinus rhythm and left-sided pacing changed only the predominance of the breakthrough. Ectopies were mapped in 10 PVs: eight showed a multifocal and two a monofocal pattern; six ectopies originated from the proximal tract of the PV.
  
  
  CONCLUSIONS
  High-density mapping of PV identifies a typical activation pattern. Multiple and discrete breakthroughs are simultaneously identified in sinus rhythm. The majority of the mapped ectopies has a multifocal pattern and proximal origin.
authors.affiliation: University of Insubria, Department of Cardiovascular Sciences "Ospedale di Circolo e Fondazione Macchi" Varese, Italy. rdponti@tin.it
authors.forename: Roberto
authors.initials: R
authors.lastname: De Ponti
authors.forename: Massimo
authors.initials: M
authors.lastname: Tritto
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Lanzotti
authors.forename: Giammario
authors.initials: G
authors.lastname: Spadacini
authors.forename: Raffaella
authors.initials: R
authors.lastname: Marazzi
authors.forename: Paolo
authors.initials: P
authors.lastname: Moretti
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Salerno-Uriarte
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000601:surgery; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000503:physiopathology* / Q000601:surgery