title: Contact forces during hybrid atrial fibrillation ablation: an in vitro evaluation.
abstract: OBJECTIVE
  Data on epicardial contact force efficacy in dual epicardial-endocardial atrial fibrillation ablation procedures are lacking. We present an in vitro study on the importance of epicardial and endocardial contact forces during this procedure.
  
  
  METHODS
  The in vitro setup consists of two separate chambers, mimicking the endocardial and epicardial sides of the heart. A circuit, including a pump and a heat exchanger, circulates porcine blood through the endocardial chamber. A septum, with a cut out, allows the placement of a magnetically fixed tissue holder, securing porcine atrial tissue, in the middle of both chambers. Two trocars provide access to the epicardium and endocardium. Force transducers mounted on both catheter holders allow real-time contact force monitoring, while a railing system allows controlled contact force adjustment. We histologically assessed different combinations of epi-endocardial radiofrequency ablation contact forces using porcine atria, evaluating the ablation's diameters, area, and volume.
  
  
  RESULTS
  An epicardial ablation with forces of 100 or 300 g, followed by an endocardial ablation with a force of 20 g did not achieve transmurality. Increasing endocardial forces to 30 and 40 g combined with an epicardial force ranging from 100 to 300 and 500 g led to transmurality with significant increases in lesion's diameters, area, and volumes.
  
  
  CONCLUSIONS
  Increased endocardial contact forces led to larger ablation lesions regardless of standard epicardial pressure forces. In order to gain transmurality in a model of a combined epicardial-endocardial procedure, a minimal endocardial force of 30 g combined with an epicardial force of 100 g is necessary.
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Pieter W J
authors.initials: PW
authors.lastname: Lozekoot
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Monique M J
authors.initials: MM
authors.lastname: de Jong
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands. sandro.gelsomino@libero.it.|Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht-CARIM, Universiteitssingel 50, 6229 ER, Maastricht, The Netherlands. sandro.gelsomino@libero.it.
authors.forename: Sandro
authors.initials: S
authors.lastname: Gelsomino
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Orlando
authors.initials: O
authors.lastname: Parise
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Francesco
authors.initials: F
authors.lastname: Matteucci
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Lucà
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Cardiothoracic Surgery, Universitair Ziekenhuis, Brussels, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Nijs
authors.affiliation: Department of Cardiothoracic Surgery, Universitair Ziekenhuis, Brussels, Belgium.
authors.forename: Jens
authors.initials: J
authors.lastname: Czapla
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Kwant
authors.affiliation: Department of Pathology, University of Florence, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Bani
authors.affiliation: Department of Cardiothoracic Surgery, University of Florence, Florence, Italy.
authors.forename: Gian Franco
authors.initials: GF
authors.lastname: Gensini
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Laurent
authors.initials: L
authors.lastname: Pison
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Harry J G M
authors.initials: HJ
authors.lastname: Crijns
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Jos G
authors.initials: JG
authors.lastname: Maessen
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Cardiothoracic Surgery, Universitair Ziekenhuis, Brussels, Belgium.
authors.forename: Mark
authors.initials: M
authors.lastname: La Meir
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003131:Combined Modality Therapy / Q000379:methods; D055119:Elastic Modulus; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D066298:In Vitro Techniques; D013314:Stress, Mechanical; D013499:Surface Properties; D013552:Swine; D014110:Touch
keywords: Atrial arrhythmias; Atrial fibrillation; Catheter ablation; Computer model simulation; Contact force