title: Relations between contact force, bipolar voltage amplitude, and mapping point distance from the left atrial surfaces of 3D ultrasound- and merged 3D CT-derived images: Implication for atrial fibrillation mapping and ablation.
abstract: BACKGROUND
  Catheter tip-derived contact force (CF) and 3-dimensional (3D) maps are key to mapping and ablation of atrial fibrillation.
  
  
  OBJECTIVE
  This study sought to determine the relation between CF and 3D map surfaces.
  
  
  METHODS
  We conducted a validation study of Carto-based 3D ultrasound (3D-US) and 3D-US merged with computed tomography (3D-Merge-CT) left atrium/pulmonary vein images. Under fluoroscopic guidance, 1361 mapping points (20 patients) with CFs and electrogram information were randomly acquired around the PVs.
  
  
  RESULTS
  CF correlated weakly with the distance of mapping points from the 3D-Merge-CT (r = 0.27; P < .001) and 3D-US (r = 0.22; P < .001) surfaces but not with bipolar voltage (r = -0.01; P = .2400). Low CF (0-4 g) yielded points close to the 3D-US surface; moderate (5-9 g) and high CFs (10-20 g) generated points beyond the surface (0.1 ± 3.9, 1.4 ± 3.4, and 2.3 ± 3.4 mm; P < .05 for each). Low, moderate, and high CFs yielded points below, close to, and beyond the 3D-Merge-CT surface (-1.2 ± 3.7, 0.4 ± 3.0, and 1.0 ± 2.9 mm; P < .05 for each).
  
  
  CONCLUSIONS
  Poor correlation between CF and the distance of mapping points from the 3D map surfaces and electrogram information shows the limitation of 3D mapping and electrogram information for predicting good contact. In addition, mapping seems to require far less CF than ablation requires.
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Sasaki
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan. Electronic address: yasuwo128@yahoo.co.jp.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Okumura
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Sonoda
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Rikitake
authors.initials: R
authors.lastname: Kogawa
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Iso
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Nakahara
authors.affiliation: Johnson & Johnson, Biosense Webster, Inc., Diamond Bar, California.
authors.forename: Ayako
authors.initials: A
authors.lastname: Maruyama
authors.affiliation: Johnson & Johnson, Biosense Webster, Inc., Diamond Bar, California.
authors.forename: Saya
authors.initials: S
authors.lastname: Takemura
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D015331:Cohort Studies; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D011312:Pressure; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: 3D CT image; 3D ultrasound image; Bipolar voltage amplitude; Contact force