title: Characterization of contact force during endocardial and epicardial ventricular mapping.
abstract: BACKGROUND
  The optimal contact force (CF) for ventricular mapping and ablation remains unvalidated. We assessed CF in different endocardial and epicardial regions during ventricular tachycardia substrate mapping using a CF-sensing catheter (Smartouch; Biosense-Webster) and compared the transseptal versus retroaortic approach.
  
  
  RESULTS
  In total, 8979 mapping points with CF, and force vector orientation (VO) were recorded in 21 patients, comprising 13 epicardial, 12 left ventricular (6 transseptal and 6 retroaortic approach), and 12 right ventricular endocardial maps. VO was defined as adequate when the vector was directed toward the myocardium. During epicardial mapping, 46% of the points showed an adequate VO and a median CF of 8 (4-13) g, however, with significant differences among the 8 regions. When VO was inadequate, median CF was higher at 16 (10-24) g (P<0.0001). During left ventricular and right ventricular endocardial mapping, 94% of VO were adequate. Median CF of adequate VO was higher in the left ventricular and right ventricular endocardium than in the epicardium (15 [8-25] and 13 [7-22] g versus 8 [4-13] g, respectively; both P<0.001). Global median left ventricular CF with transseptal approach was not statistically different from retroaortic approach, but CF in the apicoinferior and apicoseptal regions was higher with transseptal approach (P<0.001).
  
  
  CONCLUSIONS
  Ventricular mapping demonstrates important regional variations in CF, but in general, CF is higher endocardially than epicardially where poor catheter orientation is associated with higher CF. A transseptal approach may lead to improved contact particularly in the apicoseptal and inferior regions.
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France. laurence.jesel@chru-strasbourg.fr.
authors.forename: Laurence
authors.initials: L
authors.lastname: Jesel
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Sacher
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Komatsu
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Matthew
authors.initials: M
authors.lastname: Daly
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Zellerhoff
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Han S
authors.initials: HS
authors.lastname: Lim
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Derval
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Denis
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Wislane
authors.initials: W
authors.lastname: Ambri
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Khaled
authors.initials: K
authors.lastname: Ramoul
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Aurillac
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Mélèze
authors.initials: M
authors.lastname: Hocini
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
authors.affiliation: From the Department of Cardiac Electrophysiology, Bordeaux University Hospital, LIRYC Institute, INSERM 1045, Bordeaux University, Bordeaux, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Jaïs
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D062906:Cardiac Catheters; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000009:adverse effects / Q000379:methods*; D004699:Endocardium / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000009:adverse effects / Q000379:methods*; D010496:Pericardium / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology; D016896:Treatment Outcome
keywords: catheter ablation; contact force; endocardium; epicardium; ventricular tachycardia