title: Novel method for electrode-tissue contact measurement with multi-electrode catheters.
abstract: With multi-electrode catheters, measuring contact force (CF) on each electrode is technically challenging. Present electrical methods, like the electrical coupling index (ECI) may yield false positive values in pulmonary veins. We developed a novel method that measures electrode-interface resistance (IR) by applying a very local electrical field between neighbouring catheter electrodes while measuring voltage between each catheter electrode and a skin patch. The aim of this study was to evaluate the new IR method to measure electrode-tissue contact.
  
  
  
  In vitro, effects of remote high-impedance structures were studied. In addition, both ECI and IR were directly compared with true electrode-tissue CF. In five pigs, the influence of high-impedance pulmonary tissue on ECI and IR was investigated while navigating the free floating catheter into the caval veins. Inside the left atrium (LA), IR was directly compared with CF. Finally, multi-electrode IR measurements in the LA and inferior pulmonary vein (IPV) were compared. In vitro, IR is much less affected by remote high-impedance structures than ECI (3% vs. 32%). Both IR and ECI strongly relate to electrode-tissue CF (r2 = 0.84). In vivo, and in contrast to ECI, IR was not affected by nearby pulmonary tissue. Inside the LA, a strong relation between IR and CF was found. This finding was confirmed by simultaneous multi-electrode measurements in LA and IPV.
  
  
  
  Data of the present study suggest that electrode-tissue contact affects the IR while being highly insensitive to remote structures. This method facilitates electrode-tissue contact measurements with circular multi-electrode ablation catheters.
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: van Es
authors.affiliation: St. Jude Medical AF division, St Paul, MN, USA.
authors.forename: John
authors.initials: J
authors.lastname: Hauck
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
authors.forename: Vincent J H M
authors.initials: VJHM
authors.lastname: van Driel
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.|Department of Rhythmology, Alfried Krupp Krankenhaus, Essen, Germany.|Witten/Herdecke University, Witten, Germany.
authors.forename: Kars
authors.initials: K
authors.lastname: Neven
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: van Wessel
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.|Netherlands Heart Institute, Utrecht, The Netherlands.
authors.forename: Pieter
authors.initials: P
authors.lastname: A Doevendans
authors.affiliation: Department of Cardiology, University Medical Center Utrecht-Division of Heart and Lungs, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
authors.forename: Fred H M
authors.initials: FHM
authors.lastname: Wittkampf
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000295:instrumentation*; D062906:Cardiac Catheters; D017115:Catheter Ablation / Q000295:instrumentation*; D017097:Electric Impedance; D004867:Equipment Design; D006325:Heart Atria / Q000601:surgery*; D008422:Materials Testing; D023421:Models, Animal; D011667:Pulmonary Veins / Q000601:surgery*; D034421:Sus scrofa
keywords: Ablation ; Catheters; Electrode-tissue contact ; Impedance measurement 