Assessment of electrode coupling for tissue ablation

• US 20100286690A1
• Filed: 12/06/2006
• Published: 11/11/2010
• Est. Priority Date: 12/06/2005
• Status: Active Grant

• Current Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Original Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Inventors: Paul, Saurav, Cao, Hong, Thao, Chou
• Granted Patent: US 8,998,890 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 2018/00357 Endocardium
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals

Abstract

An electrode catheter and a method for assessing electrode-tissue contact and coupling are disclosed. An exemplary electrode catheter comprises an electrode adapted to apply electrical energy. A measurement circuit is adapted to measure impedance between the electrode and ground as the electrode approaches a target tissue. A processor determines a contact and coupling condition for the target tissue based at least in part on reactance of the impedance measured by the measurement circuit. In another exemplary embodiment, the electrode catheter determines the contact and coupling condition based at least in part on a phase angle of the impedance.

Claims

1. A medical system comprising

a first catheter comprising a first electrode configured for disposition within a first chamber of a heart;

a second catheter comprising a second electrode configured for disposition within said first chamber of said heart, and wherein said second electrode is a return electrode;

an electrical power system electrically connected with said first electrode; and

an electrode coupling assessment module, wherein said electrode coupling assessment module is configured to assess a coupling between said first electrode and a target tissue.

2. The medical system of claim 1, wherein said coupling is selected from the group consisting of mechanical coupling and electrical coupling.

3. The medical system of claim 1, wherein said electrode coupling assessment module comprises a phase comparator.

4. The medical system of claim 3, wherein said electrode coupling assessment module further comprises a first data structure, that in turn comprises at least one phase angle benchmark value.

5. The medical system of claim 3, wherein said electrode coupling assessment module further comprises wherein a data structure, that in turn comprises first, second, and third ranges, wherein said first range comprises phase angles associated with an insufficient coupling condition, wherein said second range comprises phase angles associated with a sufficient coupling condition, and wherein said third range comprises phase angles associated with an elevated coupling condition.

6. The medical system of claim 1, wherein said electrode coupling assessment module comprises a reactance comparator.

7. The medical system of claim 6, wherein said electrode coupling assessment module further comprises a first data structure, that in turn comprises at least one reactance benchmark value.

8. The medical system of claim 6, wherein said electrode coupling assessment module further comprises wherein a data structure, that in turn comprises first, second, and third ranges, wherein said first range comprises reactances associated with an insufficient coupling condition, wherein said second range comprises reactances associated with a sufficient coupling condition, and wherein said third range comprises reactances associated with an elevated coupling condition.

9. A medical system comprising:

a first electrode tip configured for disposition within a first chamber of a heart;

a second electrode tip configured for disposition within said first chamber of said heart

an electrical power system electrically connected with said first electrode tip; and

an electrode coupling assessment module, wherein said electrode coupling assessment module is configured to assess a coupling between said first electrode tip and a target tissue.

10. A method for performing a medical procedure, comprising the steps of:

positioning a first electrode tip in a first heart chamber;

position a second electrode tip in said first heart chamber;

sending an electrical signal to said first electrode tip; and

assessing a coupling between said first electrode tip and a target tissue using said sending step.

11. A method of claim 10, wherein a first catheter comprises said first electrode tip and a second catheter comprises said second electrode tip.

12. A method for performing a medical procedure, comprising the steps of:

positioning a first electrode in a first heart chamber, wherein a first catheter comprises said first electrode;

positioning a second catheter electrode in said first heart chamber, wherein a second catheter comprises said second electrode;

sending an electrical signal to said first electrode; and

assessing a coupling between said first electrode and a target tissue using said sending step.

13. The method of claim 12, wherein said positioning steps comprise using separate catheters.

14. The method of claim 12, wherein said coupling is selected from the group consisting of mechanical coupling and electrical coupling.

15. The method of claim 12, wherein said assessing step comprises comparing a phase angle to at least one phase angle benchmark value.

16. The method of claim 12, wherein said assessing step comprises determining if a phase angle is within one of first, second, and third ranges, wherein said first range comprises phase angles associated with an insufficient coupling condition, wherein said second range comprises phase angles associated with a sufficient coupling condition, and wherein said third range comprises phase angles associated with an elevated coupling condition.

17. The method of claim 12, wherein said assessing step comprises comparing a reactance to at least one reactance benchmark value.

18. The method of claim 12, wherein said assessing step comprises determining if a reactance is within one of first, second, and third ranges, wherein said first range comprises reactances associated with an insufficient coupling condition, wherein said second range comprises reactances associated with a sufficient coupling condition, and wherein said third range comprises reactances associated with an elevated coupling condition.

19. The method of claim 12, wherein said assessing step comprises identifying a frequency, and comparing said frequency with at least one preset value.

20. The method of claim 19, wherein said assessing step comprises identifying which of first, second, and third ranges includes said frequency, wherein said first range comprises preset values associated with an insufficient coupling condition, wherein said second range comprises preset values associated with a sufficient coupling condition, and wherein said third range comprises preset values associated with an elevated coupling condition.