Electrode having non-joined thermocouple for providing multiple temperature ...

(54) ELECTRODE HAVING NON-JOINED
THERMOCOUPLE FOR PROVIDING
MULTIPLE TEMPERATURE-SENSITIVE
JUNCTIONS

(75) Inventor: John A. Simpson, Carlsbad, CA (US)

(73) Assignee: Cardiac Pacemakers, Inc., St. Paul, MN (US)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.

This patent is subject to a terminal disclaimer.

(21) Appl. No.: 09/502,196

(22) Filed: Feb. 10, 2000

Related U.S. Application Data

(63) Continuation of application No. 09/072,853, filed on May 5, 1998, now Pat. No. 6,045,550.

(51) Int. CI.7 A61B 18/18

(52) U.S. CI 606/42; 607/102; 600/549

(58) Field of Search 606/31-35, 41,

606/42, 45-50; 607/101, 102; 600/374,

549

(56) References Cited

U.S. PATENT DOCUMENTS

4,411,266 A * 10/1983 Cosman 606/50

4,966,597 A * 10/1990 Cosman 606/50

5,688,266 A * 11/1997 Edwards et al 606/31

5,893,885 A * 4/1999 Webster, Jr. 67/122

OTHER PUBLICATIONS

ISHM '87 Proceedings "Taming Thermocouple Voltages in

Microelectronics" by Roy Chapel, pp. 104—112.

"The Thermocouple", Omega Catalog, vol. 27, pp. Z9-Z20.

* cited by examiner

Primary Examiner—Michael Peftley

(74) Attorney, Agent, or Firm—Fulwider Patton Lee &

Utecht, LLP

(57) ABSTRACT

The non-joined thermocouple electrode configuration, for use in an RF ablation catheter for ablating biological tissue such as cardiac tissue, allows temperature to be monitored at two locations of a band electrode while only using a single pair of thermocouple wires. The thermocouple wires are connected to the electrode at separate locations. They preferably are formed of metallic materials having Seebeck coefficients that are substantially equal in magnitude but opposite in sign relative to the electrode material connecting the two. In the case of a band electrode, the two thermocouple wires are preferably spaced apart on the band electrode so that the first junction contacts the tissue having a first temperature and the second junction contacts circulating blood having a second temperature. The voltage across the thermocouple wires provides an indication of the average of the two junctions temperatures so that by monitoring the temperature of the blood, the temperature of the first junction can be determined from this average temperature.

18 Claims, 16 Drawing Sheets