title: Improved electrogram attenuation during ablation of paroxysmal atrial fibrillation with the Hansen robotic system.
abstract: BACKGROUND
  Robotic catheter ablation aims to improve outcomes after ablation of atrial fibrillation (AF) through improved lesion quality. This study examined electrogram attenuation as a measure of efficacy in response to robotic (ROB) and manual (MAN) ablation.
  
  
  METHODS
  Patients with paroxysmal AF undergoing ablation as part of an ongoing randomized controlled trial were studied (Clinical Trials Registration NCT01037296). Patients underwent pulmonary vein isolation using NavX (St. Jude Medical, St. Paul, MN, USA). Patients were randomized to MAN or ROB catheter ablation using a 3.5-mm irrigated-tip catheter with standardized ablation settings. Bipolar electrogram voltage was measured at 0, 5, 10, 20, and 30 seconds after ablation onset. Distance from ablation lesion to the left atrial surface on NavX were calculated.
  
  
  RESULTS
  Similar ablation energy was delivered in ROB and MAN groups, achieving comparable rates of PV isolation (100% vs 98%). The bipolar voltages of 4,434 electrograms from 303 ablation lesions (146 ROB, 157 MAN) were measured. At 30 seconds, signal attenuation was greater in the ROB group than MAN (mean 65 ± 4% vs 55 ± 4% of baseline voltage, P < 0.01). A total of 2,064 NavX ablation lesions were assessed (906 ROB and 1,158 MAN). ROB lesions were on average 0.52 mm further inside the geometry than MAN (P < 0.0001).
  
  
  CONCLUSIONS
  Robotic ablation results in greater signal attenuation in man. This is achieved despite manual lesions being closer to the left atrial surface. Catheter stability and constant energy delivery may be key to achieving signal attenuation, rather than increased contact force.
authors.affiliation: Department of Cardiology, Barts and the London NHS Trust, London, United Kingdom.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Duncan
authors.forename: Malcolm
authors.initials: M
authors.lastname: Finlay
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Page
authors.forename: Ross
authors.initials: R
authors.lastname: Hunter
authors.forename: Farai
authors.initials: F
authors.lastname: Goromonzi
authors.forename: Laura
authors.initials: L
authors.lastname: Richmond
authors.forename: Victoria
authors.initials: V
authors.lastname: Baker
authors.forename: Matthew
authors.initials: M
authors.lastname: Ginks
authors.forename: Vivienne
authors.initials: V
authors.lastname: Ezzat
authors.forename: Mehul
authors.initials: M
authors.lastname: Dhinoja
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Earley
authors.forename: Simon
authors.initials: S
authors.lastname: Sporton
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Schilling
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012371:Robotics / Q000295:instrumentation*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D016896:Treatment Outcome