Ablation system and method of use

• US 7,824,399 B2
• Filed: 02/16/2006
• Issued: 11/02/2010
• Est. Priority Date: 04/26/2001
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Skarda, James R., Mehra, Rahul, Warman, Eduardo N., Francischelli, David E., Schwartzman, David, Puryear, Harry, Stewart, Mark T.
• Primary Examiner(s): Dvorak; Linda C
• Assistant Examiner(s): GOOD, SAMANTHA M
• Application Number:
  US11/355,465
• Publication Number:
  US 20060142753A1
• Time in Patent Office: 1,720 Days
• Field of Search: 606 32- 34, 606 41- 42, 607/101, 607/102, 607/116, 607/122, 600/508, 600/510
• US Class Current: 606/34
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
• CPC Class Codes: A61B 2018/00065 porous
• CPC Class Codes: A61B 2018/00363 Epicardium
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00755 Resistance or impedance
• CPC Class Codes: A61B 2018/00779 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/1226 powered by a battery
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/126 bipolar
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61N 1/403 for thermotherapy, e.g. hyperthermia

Abstract

A system and method for creating lesions and assessing their completeness or transmurality. Assessment of transmurality of a lesion is accomplished by monitoring the depolarization signal in a local electrogram taken using electrodes located adjacent the tissue to be ablated. Following onset of application of ablation energy to heart tissue, the local electrogram is measured with electrodes located adjacent tissue to be ablated so that the ablation energy to ablation elements can be selectively reduced or terminated when transmurality is detected.

Claims

1. An ablation system, comprising:

a generator for generating ablation energy;

an ablation device comprising an ablation element operably coupled to the generator and locatable adjacent a tissue site to be ablated, for applying ablation energy to the tissue site;

an electrogram measurement element mounted to the ablation device so that the electrogram measurement element is adjacent the tissue site when the ablation element is adjacent the tissue site;

electrogram amplitude measurement circuitry operably coupled to the electrogram measurement element to measure electrogram amplitude at the tissue site, using the electrogram measurement element; and

control circuitry operably coupled to the generator to initiate and terminate the application of ablation energy to the ablation element, wherein the control circuitry is operably coupled to the electrogram amplitude measurement circuit and terminates application of ablation energy to the ablation element responsive to occurrence of a plateau in the electrogram amplitude measured by the electrogram amplitude measurement circuitry following initiation of application of ablation energy to the ablating element.

2. The system of claim 1 wherein the ablation element is an ablation electrode.

3. The system of claim 2 wherein the ablation electrode is an irrigated ablation electrode.

4. The system of claim 2 wherein the ablation electrode is employed as the electrogram measurement element.

5. The system of claim 1 wherein the electrogram measurement element is an electrogram measurement electrode.

6. The system of claim 1 wherein the generator is an R-F generator.

7. The system of claim 1 wherein the ablation energy is R-F energy.

8. The system of claim 1 wherein the ablation energy is microwave radiation.

9. The system of claim 1 wherein the ablation energy is laser energy.

10. The system of claim 1 wherein the ablation energy is heat energy.

11. The system of claim 1 wherein the ablation energy is ultrasound energy.

12. An ablation system, comprising:

a generator for generating ablation energy;

an ablation device comprising an ablation element operably coupled to the generator and locatable adjacent a tissue site to be ablated, for applying ablation energy to the tissue site;

an electrogram measurement element mounted to the ablation device so that the electrogram measurement element is adjacent the tissue site when the ablation element is adjacent the tissue site;

electrogram amplitude measurement circuitry operably coupled to the electrogram measurement element to measure electrogram amplitude at the tissue site, using the electrogram measurement element; and

control circuitry operably coupled to the generator to initiate and terminate the application of ablation energy to the ablation element, wherein the control circuitry is operably coupled to the electrogram amplitude measurement circuit and reduces the level of ablation energy to the ablation element responsive to occurrence of a rapid drop in the electrogram amplitude measured by the electrogram amplitude measurement circuitry following initiation of application of ablation energy to the ablating element.

13. The system of claim 12 wherein the ablation element is an ablation electrode.

14. The system of claim 13 wherein the ablation electrode is an irrigated ablation electrode.

15. The system of claim 13 wherein the ablation electrode is employed as the electrogram measurement element.

16. The system of claim 12 wherein the electrogram measurement element is an electrogram measurement electrode.

17. The system of claim 12 wherein the generator is an R-F generator.

18. The system of claim 12 wherein the ablation energy is R-F energy.

19. The system of claim 12 wherein the ablation energy is microwave radiation.

20. The system of claim 12 wherein the ablation energy is laser energy.

21. The system of claim 12 wherein the ablation energy is heat energy.

22. The system of claim 12 wherein the ablation energy is ultrasound energy.

23. An ablation system, comprising:

a generator for generating ablation energy;

an ablation device comprising an ablation element operably coupled to the generator and locatable adjacent a tissue site to be ablated, for applying ablation energy to the tissue site;

an electrogram measurement element mounted to the ablation device so that the electrogram measurement element is adjacent the tissue site when the ablation element is adjacent the tissue site;

electrogram amplitude measurement circuitry operably coupled to the electrogram measurement element to measure electrogram amplitude at the tissue site, using the electrogram measurement element; and

control circuitry operably coupled to the generator to initiate and terminate the application of ablation energy to the ablation element, wherein the control circuitry is operably coupled to the electrogram amplitude measurement circuit and terminates the application of ablation energy to the ablation element responsive to occurrence of a drop in the electrogram amplitude measured by the electrogram amplitude measurement circuitry following initiation of application of ablation energy to the ablating element.

24. The system of claim 23 wherein the ablation element is an ablation electrode.

25. The system of claim 24 wherein the ablation electrode is an irrigated ablation electrode.

26. The system of claim 24 wherein the ablation electrode is employed as the electrogram measurement element.

27. The system of claim 23 wherein the electrogram measurement element is an electrogram measurement electrode.

28. The system of claim 23 wherein the generator is an R-F generator.

29. The system of claim 23 wherein the ablation energy is R-F energy.

30. The system of claim 23 wherein the ablation energy is microwave radiation.

31. The system of claim 23 wherein the ablation energy is laser energy.

32. The system of claim 23 wherein the ablation energy is heat energy.

33. The system of claim 23 wherein the ablation energy is ultrasound energy.