Catheter having needle electrode for radiofrequency ablation

• US 5,281,218 A
• Filed: 06/05/1992
• Issued: 01/25/1994
• Est. Priority Date: 06/05/1992
• 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.
• Primary Examiner(s): ASCHENBRENNER, PETER
• Application Number:
  US07/894,409
• Time in Patent Office: 599 Days
• Field of Search: 606/29, 606/28, 606/30, 606/32, 606/33, 606/41, 128/784, 128/786, 128/804
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1477 Needle-like probes
• 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 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2018/00196 reciprocating lengthwise
• CPC Class Codes: A61B 2018/1425 Needle
• CPC Class Codes: A61F 2210/0033 electrically, e.g. heated by resistor
• CPC Class Codes: A61M 25/0147 with movable mechanical means, e.g. pull wires

Abstract

A catheter for use in radiofrequency ablation of the myocardium of the heart of a patient having a flexible elongate member with at least one lumen extending therethrough and having proximal and distal extremities. A needle-like electrode formed of a conducting material is mounted on the distal extremity of the flexible elongate member. A conductor extends through the lumen and is connected to the electrode. Radiofrequency energy is supplied to to said conductor and to the electrode to cause ablation of the myocardium.

Claims

1. In a catheter for use in radiofrequency ablation of the myocardium of the heart of a patient, a flexible elongate member having at least one lumen extending therethrough and having proximal and distal extremities, a solid needle-like electrode formed solely of a conducting material mounted on the distal extremity of the flexible elongate member, a conductor extending through said lumen and connected to said electrode and means for supplying radiofrequency energy to said conductor and said electrode to cause ablation of the myocardium.

2. A catheter as in claim 1 wherein said needle electrode has a diameter of 0.002 inches to 0.008 inches and has a length ranging from 0.5 to 1 cm.

3. A catheter as in claim 1 wherein said flexible elongate member is sufficiently rigid so that force can be applied to the proximal extremity thereof to cause the needle to penetrate the myocardium.

4. A catheter as in claim 1 together with means carried by the distal extremity of the flexible elongate member for extending and retracting said needle-like electrode.

6. A catheter as in claim 4 wherein said means for extending or retracting said needle-like electrode includes push-pull wire having proximal and distal extremities extending through the lumen in the catheter, said needle-like electrode being mounted on the distal extremity of the push-pull wire and means secured to the proximal extremity of the push-pull wire for manually advancing and retracting the same.

7. A catheter as in claim 1 together with a seal disposed on the distal extremity of the flexible elongate element and having a sealable opening therein through which the needle-like electrode can extend and retract.

8. A catheter as in claim 1 together with means for causing as steering movement of the distal extremity of the flexible elongate member.

9. A catheter as in claim 8 wherein said means for causing steering includes at least three elongate elements disposed approximately 120°

apart or less within the flexible elongate member and means for selectively applying energy to said flexible elongate elements to cause steering movement of the distal extremity of the catheter.

5. In a catheter for use in radiofrequency ablation of the myocardium of the heart of a patient, a flexible elongate member having at least one lumen extending therethrough and having proximal and distal extremities, a needle-like electrode formed of a conducting material mounted on the distal extremity of the flexible elongate member, a conductor extending through said lumen and connected to said electrode, means for supplying radiofrequency energy to said conductor and said electrode to cause ablation of the myocardium and means carried by the distal extremity of the flexible elongate member for extending and retracting said needle-like electrode;

said means for extending and retracting said needle-like electrode including first and second spring members of a material having a negative coefficient of expansion and means for securing said spring members to said needle-like electrode so that when one of the first and second spring members is energized, the needle-like electrode is retracted and when the other of the first and second spring members is energized, the needle-like electrode is extended.