title: Radiofrequency ablation with a vibrating catheter: A new method for electrode cooling.
abstract: A new electrode cooling system using a vibrating catheter is described for conditions of low blood flow when saline irrigation cannot be used. Vibrations of the catheter are hypothesized to disturb blood flow around the electrode, leading to increased convective cooling of the electrode. The aim of this study is to confirm the cooling effect of vibration and investigate the associated mechanisms. As methods, an in vitro system with polyvinyl alcohol-hydrogel (PVA-H) as ablated tissue and saline flow in an open channel was used to measure changes in electrode and tissue temperatures under vibration of 0-63 Hz and flow velocity of 0-0.1 m/s. Flow around the catheter was observed using particle image velocimetry (PIV). Results show that under conditions of no flow, electrode temperatures decreased with increasing vibration frequency, and in the absence of vibrations, electrode temperatures decreased with increasing flow velocity. In the presence of vibrations, electrode temperatures decreased under conditions of low flow velocity, but not under those of high flow velocity. PIV analyses showed disturbed flow around the vibrating catheter, and flow velocity around the catheter increased with higher-frequency vibrations. In conclusion, catheter vibration facilitated electrode cooling by increasing flow around the catheter, and cooling was proportional to vibration frequency.
authors.affiliation: Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Kaihong
authors.initials: K
authors.lastname: Yu
authors.affiliation: Cardiovascular Internal Medicine System Sec., JMS Co., Ltd., Tokyo, Japan.
authors.forename: Tetsui
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: R&D Center, Nidec Copal Electronics Corp. Sano, Tochigi, Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Shingyochi
authors.affiliation: Cardiology Department, Saitama Medical University, Hidaka, Saitama, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Matsumoto
authors.affiliation: Institute of Fluid Science, Tohoku University, 2-1-1 Katahira Aoba-ku, 980-8577 Sendai, Miyagi, Japan. Electronic address: ohta@biofluid.ifs.tohoku.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohta
mesh_terms: D032701:Biomimetics; D017115:Catheter Ablation / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D057446:Hydrodynamics; D020100:Hydrogels; D011142:Polyvinyl Alcohol; D013696:Temperature; D013997:Time Factors; D014732:Vibration
chemical_list: D020100:Hydrogels; D011142:Polyvinyl Alcohol
keywords: Catheter ablation; Electrode cooling; Electrode temperature; Myocardium; PIV; PVA-H