title: Prospective evaluation of a novel catheter equipped with mini electrodes on a 10-mm tip for cavotricuspid isthmus ablation - The efficacy of a mini electrode guided ablation.
abstract: BACKGROUND
  Clinical utility of large-tip ablation catheters for cavo-tricuspid isthmus (CTI) ablation has been reported, however, it is limited by the impaired near-field electrogram resolution. This study evaluated the efficiency of a novel mini-electrode (ME) equipped 10-mm tip CTI ablation catheter.
  
  
  METHODS
  Thirty-four patients were prospectively enrolled (Group-A). Initially, radiofrequency energy was applied point-by-point guided by ME signals. If it failed, RF applications were applied conventionally guided by tip-ring signals. The data were compared with 32 and 32 patients undergoing CTI ablation using 8-mm tip (Group-B) and 3.5-mm irrigation-tip (Group-C) catheters, respectively.
  
  
  RESULTS
  The successful CTI block creation rate was significantly higher in Group-A and Group-B than Group-C (32/34[94.1%], 31/32[96.8%], and 25/32[78.1%], p=0.027). In Group-A, ME guided ablation was successful in 30 patients and subsequent conventional ablation in 2. There was no significant difference between the 3 groups for the total procedure and fluoroscopic times using the initial catheters. However, the total radiofrequency applications (6.9±3.6, 9.9±4.3, and 12.0±7.1, p=0.001), total radiofrequency time (358±197, 558±248, and 566±265s, p=0.001), and radiofrequency time to achieve initial block (222±159, 471±242, and 396±211s, p<0.001) were significantly shorter in Group-A than Group-B and Group-C. In Group-A, a maximal ME amplitude attenuation (86±13%, from 0.84±0.53 to 0.08±0.04mV) was obtained by 19.0±6.5s mean applications. Maximal tip-ring amplitude attenuation (76±17%, from 0.58±0.29 to 0.12±0.09mV) was obtained by 22.1±6.2s mean applications.
  
  
  CONCLUSIONS
  ME guided ablation using a novel ME equipped 10-mm tip ablation catheter was feasible for human CTI ablation, and might reduce inadvertent radiofrequency applications.
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan; Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan; Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Takagi
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan. Electronic address: mshinsuke@k3.dion.ne.jp.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Miyazaki
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Niida
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kajiyama
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kusa
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hachiya
authors.affiliation: Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Iesaka
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
authors.affiliation: Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hirao
mesh_terms: D000368:Aged; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D057785:Catheters; D004867:Equipment Design / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*
keywords: Catheter ablation; Cavo-tricuspid isthmus; Far-field potential; Large tip catheter; Mini-electrode