title: Robot-assisted epicardial ablation of the pulmonary veins: is a completed isolation necessary?
abstract: OBJECTIVE
  To study the feasibility and electrophysiological efficacy of minimally invasive beating heart ablation of the pulmonary veins (PVs) via a robot-assisted single-sided approach.
  
  
  BACKGROUND
  PV isolation by minimally invasive epicardial ablation may offer a new treatment for patients with lone atrial fibrillation (AF). However, complete PV isolation has been shown to be difficult to obtain.
  
  
  RESULTS
  In 14 mongrel dogs, robot-assisted epicardial microwave ablation was performed on the beating heart by a single-sided right chest approach. Isolation of all PVs was performed in two steps to study the effect of an incomplete and a complete isolation on AF. AF was studied by random and burst pacing. Incremental pacing was performed to study conduction characteristics across the lesions. Opening of the pericardial reflections, introduction of the catheter and ablation were robotically feasible by a single-sided approach in 11 dogs. The AF duration decreased from 6.6+/-4.1 to 1.3+/-0.8 s (P=0.03) and 1.6+/-1.6 s (P=0.04 compared with control) after incomplete and completed isolation of the PVs. The AF cycle length increased from 134+/-5 to 141+/-5 and 145+/-8 ms (P=0.03) after incomplete and complete isolation, respectively. Several incomplete lesions showed 2:1 exit and/or entrance block during incremental pacing. After complete isolation, AF was no longer inducible from the PVs.
  
  
  CONCLUSIONS
  Epicardial PV isolation can be successfully performed by a single-sided robot-assisted approach. The effect of PV ablation on AF is not an all or none phenomenon. Incomplete isolation already decreases AF duration and lengthens the AF cycle length. However, complete isolation is necessary to prevent AF induction by triggering from the isolated area.
authors.affiliation: Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht, University Hospital Maastricht, P. Debyelaan 25, Postbus 5800, 6202 AZ Maastricht, The Netherlands. t.vanbrakel@ctc.unimaas.nl
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: van Brakel
authors.forename: Gil
authors.initials: G
authors.lastname: Bolotin
authors.forename: L Wiley
authors.initials: LW
authors.lastname: Nifong
authors.forename: André L A J
authors.initials: AL
authors.lastname: Dekker
authors.forename: Maurits A
authors.initials: MA
authors.lastname: Allessie
authors.forename: W Randolph
authors.initials: WR
authors.lastname: Chitwood
authors.forename: Jos G
authors.initials: JG
authors.lastname: Maessen
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D004285:Dogs; D004594:Electrophysiology; D005240:Feasibility Studies; D011667:Pulmonary Veins / Q000601:surgery*; D012371:Robotics