title: Operator-blinded contact force monitoring during pulmonary vein isolation using conventional and steerable sheaths.
abstract: BACKGROUND
  We performed contact force (CF) monitoring during pulmonary vein (PV) isolation to evaluate CF according to sheath type, catheter position, and inadequate ablation.
  
  
  METHODS
  Thirty consecutive patients (paroxysmal atrial fibrillation, 23; CHADS2 score, 0.5 ± 0.7; age, 56 ± 10 years) who underwent PV isolation using a CF-sensing catheter were included. Data for operator-blinded CF, impedance, and duration of the "first touch" (first round of ablation in each PV) was collected. We compared the CF, maximum CF, force-time integral, average impedance, and impedance drop (Δ impedance) between different sheaths (Swartz™ vs. Agilis™) in 12 different catheter positions, and in inadequate first touches requiring additional ablation.
  
  
  RESULTS
  A total of 1283 ablation points (Swartz™, 620 points; Agilis™, 663 points) were evaluated. The average CF was significantly higher in the Agilis™ group (17.8 ± 13.0 g) than the Swartz™ group (15.0 ± 12.4 g; P < 0.001), especially in the anterior, inferior-anterior, and inferior-posterior sections of the right PV, and the top of the roof, and calina of the left PV. The Δ impedance showed a mildly significant negative relationship with the average CF (r=-0.206; P<0.001) and with the force-time integral (r = -0.279; P < 0.001). Compared to first touches, the average CF and Δ impedance were significantly smaller in inadequate first touches in the Swartz™ group, but not in the Agilis™ group.
  
  
  CONCLUSIONS
  CF for PV isolation was significantly different depending on the position of the catheter and the type of sheath.
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan. Electronic address: kimura@z7.keio.jp.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takatsuki
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Ako
authors.initials: A
authors.lastname: Oishi
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masachika
authors.initials: M
authors.lastname: Negishi
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Kashimura
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Katsumata
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nishiyama
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tanimoto
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Aizawa
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
mesh_terms: D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging* / Q000601:surgery*; D016037:Single-Blind Method; D016896:Treatment Outcome; D014463:Ultrasonography
keywords: Atrial fibrillation; Contact force; Pulmonary vein isolation; Radiofrequency catheter ablation