title: Modifications in ventricular fibrillation and capture capacity induced by a linear radiofrequency lesion.
abstract: OBJECTIVE
  An analysis was made of the effects of a radiofrequency-induced linear lesion during ventricular fibrillation and the capacity to capture myocardium through high-frequency pacing.
  
  
  METHODS
  Using multiple epicardial electrodes, ventricular fibrillation was recorded in 22 isolated perfused rabbit hearts, analyzing the activation maps upon applying trains of stimuli at 3 different frequencies close to that of the arrhythmia: a) at baseline; b) after radio-frequency ablation to induce a lesion of the left ventricular free wall (length=10 [1] mm), and c) after lengthening the lesion (length=23 [2] mm).
  
  
  RESULTS
  Following lesion induction, the regularity of the recorded signals decreased and significant variations in the direction of the activation fronts were observed. On lengthening the lesion, there was a slight increase in the episodes with at least 3 consecutive captures when pacing at cycles 10% longer than the arrhythmia (baseline: 0.6 [0.7]; initial lesion: 1 [1], no significant differences; lengthened lesion: 3 [2.8]; P<.001), while a decrease was observed in those obtained upon pacing at cycles 10% shorter than the arrhythmia.
  
  
  CONCLUSIONS
  The radio-frequency -induced lesion increases the heterogeneity of myocardial activation during ventricular fibrillation and modifies arrival of the activation fronts in the adjacent zones. High-frequency pacing during ventricular fibrillation produces occasional captures during at least 3 consecutive stimuli. The lengthened lesion in turn slightly increases capture capacity when using cycles slightly longer than the arrhythmia.
authors.affiliation: Servicio de Cardiología, Hospital Clínico Universitario de Valencia, INCLIVA, Valencia, Spain. Francisco.J.Chorro@uv.es
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Chorro
authors.forename: Francisca
authors.initials: F
authors.lastname: Pelechano
authors.forename: Isabel
authors.initials: I
authors.lastname: Trapero
authors.forename: Xavier
authors.initials: X
authors.lastname: Ibañez-Catalá
authors.forename: Luis
authors.initials: L
authors.lastname: Such-Miquel
authors.forename: Alvaro
authors.initials: A
authors.lastname: Tormos
authors.forename: Juan
authors.initials: J
authors.lastname: Guerrero
authors.forename: Joaquín
authors.initials: J
authors.lastname: Cánoves
authors.forename: Luis
authors.initials: L
authors.lastname: Mainar
authors.forename: José
authors.initials: J
authors.lastname: Millet
authors.forename: Antonio
authors.initials: A
authors.lastname: Alberola
authors.forename: Luis
authors.initials: L
authors.lastname: Such
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects*; D004562:Electrocardiography; D004566:Electrodes; D066298:In Vitro Techniques; D009206:Myocardium / Q000473:pathology; D011817:Rabbits; D011846:Radio Waves / Q000009:adverse effects*; D014693:Ventricular Fibrillation / Q000209:etiology* / Q000473:pathology