Catheter for RF ablation with cooled electrode and apparatus for use therewith

• US 5,697,927 A
• Filed: 03/16/1994
• Issued: 12/16/1997
• Est. Priority Date: 12/01/1992
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Inventors: Imran, Mir A., Pomeranz, Mark L.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/210,032
• Time in Patent Office: 1,371 Days
• Field of Search: 606/41, 606/45, 606/49, 607/98, 607/99, 607/101, 607/102, 607/104, 607/105, 607/113, 607/116, 607/122
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00035 with return means
• CPC Class Codes: A61B 2018/00166 Multiple lumina
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00821 measured by a thermocouple

Abstract

A catheter for radio frequency ablation with a cooled electrode for use in tissue having a surface comprising an elongate member having proximal and distal extremities. A metal conducting electrode secured to the distal extremity of the elongate member and having a chamber therein. A conductor extends through the elongate member from the proximal to the distal extremity for supplying radio frequency energy to the electrode. The elongate member has a lumen in the distal extremity which is in communication with the chamber. A coolant is disposed in the chamber and in contact with the electrode for dissipating heat created in the electrode by the application of radio frequency energy thereto.

Claims

1. A catheter for cooled radio frequency ablation for use in tissue having blood therein and having a surface comprising an elongate member having proximal and distal extremities, a cup-shaped metal conducting electrode having a continuous circumferentially exposed exterior surface secured to the distal extremity of the elongate member and having a chamber therein, said cup-shaped metal conducting electrode having a tip with a rounded exposed exterior surface and a continuous cylindrical exposed exterior surface adjoining the rounded exposed surface, said metal conducting electrode being adapted to contact said surface of said tissue, conductor means extending through the elongate member from the proximal to the distal extremity for supplying radio frequency energy to the electrode, said conductor means and said metal conducting electrode being formed to permit in excess of 10 watts of power to be delivered from the metal conducting electrode into the tissue to form the wide and deep lesions, said elongate member having a lumen in the distal extremity and extending from the proximal extremity and in communication with the chamber and cooling means disposed in said chamber and in contact with the electrode for dissipating heat created in the metal conducting electrode when radio frequency energy is supplied to the metal conducting electrode to create a necrosis in the tissue below the surface and for inhibiting the coagulation of blood on the metal conducting electrode.

2. A catheter for cooled radio frequency ablation for use in tissue having a surface comprising an elongate member having proximal and distal extremities, a metal conducting electrode secured to the distal extremity of the elongate member and having a chamber therein, conductor means extending through the elongate member from the proximal to the distal extremity for supplying radio frequency energy to the electrode, said elongate member having a lumen in the distal extremity and being in communication with the chamber and active cooling means disposed in said chamber and in contact with the electrode and including a cooled liquid having a temperature ranging from 5°

to 10°

C. for dissipating heat created in the electrode by the application of radio frequency energy thereto, said electrode is a tip electrode having a rounded tip having orifices therein through which the cooled liquid can pass from the chamber, said tip electrode having a longitudinally extending axis, said tip electrode being provided with an additional orifice inclined proximally in a direction extending away from the axis of the tip electrode through which the cooled liquid can escape to create jets which create forces to urge the electrode into engagement with the surface.

3. A catheter for radio frequency ablation with a cooled electrode for use in tissue having a surface comprising an elongate member having proximal and distal extremities, a cylindrical cup-shaped metal conducting electrode secured to the distal extremity of the elongate member and having a chamber therein, said cup-shaped metal conductive electrode having a tip with a rounded exposed exterior surface and a continuous cylindrical exposed exterior surface adjoining the rounded exposed surface, conductor means extending through the elongate member from the proximal to the distal extremity for supplying radio frequency energy to the electrode, said metal conducting electrode and said conductor means being formed to supply in excess of 10 watts of power into the tissue, said elongate member having a lumen therein extending from the proximal extremity to the distal extremity and being in communication with the chamber and liquid cooling means coupled to the proximal extremity supplying a cooling liquid to said lumen and to said chamber and into contact with the metal conducting electrode for dissipating heat created in the metal conducting electrode by the application of radio frequency energy to the metal conducting electrode.

4. A system for controlling the temperature of an energy delivering electrode disposed on an ablation catheter comprising a thin, flexible elongate catheter having a lumen disposed therein to enable fluid to be conveyed through the catheter at a variable rate of flow, the catheter having at least one energy delivering electrode disposed at a distal portion of the catheter and the catheter having dimensions suitable for intravascular delivery, said at least one energy delivering electrode being cup-shaped and having a tip with a rounded exposed exterior surface and a continuous cylindrical exposed exterior surface adjoining the rounded exposed surface, a radio frequency power supply in electrical communication with the catheter for providing a desired radio frequency energy output in excess of 10 watts to the energy delivering electrode for delivery to tissue adjacent the energy delivering electrode, a liquid supply source in communication with the lumen temperature sensing means associated with the catheter for sensing the temperature of the energy delivering electrode and generating a signal representative of measured electrode temperature, and fluid control means for regulating the rate of flow of liquid through the lumen.

5. A system as in claim 4 wherein the temperature sensing means comprises a thermocouple.

6. A system for controlling the temperature of an energy delivering electrode disposed on an ablation catheter for delivering radio frequency energy into tissue comprising a thin, flexible elongate catheter having a lumen disposed therein to enable fluid to be conveyed through the catheter at a variable rate of flow for delivery to a distal portion of the catheter, the catheter having at least one energy delivering cup-shaped metal conducting electrode disposed at a distal portion of the catheter and formed to deliver in excess of 10 watts of power into the tissue, the catheter having dimensions suitable for intravascular delivery, said energy delivering cup-shaped metal conducting electrode having a tip with a rounded exposed exterior surface and a continuous cylindrical exposed exterior surface adjoining the rounded exposed surface, a radio frequency power supply in electrical communication with the catheter for providing a desired electrosurgical energy output in excess of 10 watts to the electrode for delivery to tissue adjacent the electrode, a fluid supply source in communication with the lumen and providing a liquid through the lumen and into contact with the energy delivering electrode, temperature sensing means associated with the catheter for sensing the temperature of the energy delivering electrode and generating a signal representative of measured electrode temperature and fluid control means for regulating the rate of flow of fluid through the lumen to maintain the measured electrode temperature at or below a predetermined maximum temperature value.