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FLEXIBLE ELECTRODE FOR RF ABLATION

IP.com Disclosure Number: IPCOM000192637D
Publication Date: 2010-Jan-26
Document File: 4 page(s) / 366K

Publishing Venue

The IP.com Prior Art Database

Abstract

An RF ablation catheter includes a flexible electrode formed of a wire mesh bonded to the distal end of a catheter shaft. The catheter also includes a pull wire, the distal end of which is attached to the interior distal portion of the electrode. The proximal end of the pull wire is configured to be withdrawn proximally relative to the catheter shaft, thereby retracting the electrode into the distal end of the catheter shaft. Infusion fluid is delivered through the lumen of the catheter shaft, thereby inflating and deploying the electrode from the distal end of the shaft.

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FLEXIBLE ELECTRODE FOR RF ABLATION

Abstract:  An RF ablation catheter includes a flexible electrode formed of a wire mesh bonded to the distal end of a catheter shaft.  The catheter also includes a pull wire, the distal end of which is attached to the interior distal portion of the electrode.  The proximal end of the pull wire is configured to be withdrawn proximally relative to the catheter shaft, thereby retracting the electrode into the distal end of the catheter shaft.  Infusion fluid is delivered through the lumen of the catheter shaft, thereby inflating and deploying the electrode from the distal end of the shaft.

Figs. 1A and 1B depict the distal portion of an RF ablation catheter 10 in retracted and deployed configurations, respectively.  The distal portion of the ablation catheter 10 generally includes a flexible electrode 16 attached to the interior surface of the distal end 18 of a catheter shaft 12.  The electrode 16 may be formed of a woven wire mesh of conductive metal, such as stainless steel.  The wire forming the mesh has a small diameter, such that the electrode 16 is flexible enough to be retracted into, and extruded from, the distal end 18 of the shaft 12.  The catheter 10 also includes an elongated pull wire 20 disposed within a lumen 14 of the catheter shaft 12.  The distal end 22 of the pull wire 20 is bonded to the distal portion of the electrode 16, and the proximal end of the pull wire 20 (not shown) extends from the proximal end of the catheter shaft 12 (also not shown).  The pull wire 20 is thus configured to fully withdraw the electrode 16 into the shaft lumen 14, as shown in Fig. 1A, by pulling the wire 20 proximally relative to the shaft 12.  

In order to deploy the electrode 16, as shown in Fig. 1B, infusion fluid, such as saline or D5W, is delivered through the shaft lumen 14 toward the electrode 16, thereby inflating and deploying the electrode 16 from the distal end 18 of the shaft 12.  With an open irrigated design, the woven wire mesh of the electrode 16 is somewhat porous, and the infusion fluid cools the wire mesh and exits next to the target tissue or into the blood.  The infusion liquid may contain heparin to prevent coagulation on or in the electrode 16 during or between procedures.  Since a low pressure may be continually maintained inside the electrode 16, blood is unlikely to enter the electrode 16.  However, the heparin insures that clotting will not be a problem with this design.

During use, the catheter 10 is inserted into a patient’s body and positioned adjacent to target tissue where RF ablation is to be performed.  Fig. 2 depi...