RF Energy Delivery System and Method

• US 20080281322A1
• Filed: 05/08/2008
• Published: 11/13/2008
• Est. Priority Date: 05/11/2007
• Status: Active Grant

• Current Assignee: Medtronic Ablation Frontiers LLC (Medtronic Plc)
• Original Assignee: Ablation Frontiers Incorporated (Medtronic Plc)
• Inventors: Flaherty, J. Christopher, Werneth, Randell L., Sherman, Marshall L.
• Granted Patent: US 8,771,269 B2
• Time in Patent Office: Days
• US Class Current: 606/42
• CPC Class Codes: A61B 18/1206 Generators therefor
• 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 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00375 Ostium, e.g. ostium of pulmonary vein or artery
• CPC Class Codes: A61B 2018/1407 Loop
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1475 Electrodes retractable in or deployable from a housing

Abstract

A radio frequency tissue ablation system with a radio frequency generator, the generator comprising a radio frequency source, at least four independently controllable radio frequency outputs, a user interface and a controller configured to delivery radio frequency energy from the radio frequency source to the radio frequency outputs in one of at least two different output configurations in response to a configuration selection made through the user.

Claims

1. A radio frequency tissue ablation system comprising a radio frequency generator, the generator comprising a radio frequency source, at least four independently controllable radio frequency outputs, a user interface and a controller configured to delivery radio frequency energy from the radio frequency source to the radio frequency outputs in one of at least two different output configurations in response to a configuration selection made through the user interface.

2. The system of claim 1 wherein the controller is further configured to operate each output in either a monopolar mode or in a bipolar mode.

3. The system of claim 2 further comprising a ground pad, the ground pad being connected to a ground source when the outputs are operated in both monopolar mode and bipolar mode.

4. The system of claim 2 wherein the controller is further configured to operate each output in a combination monopolar/bipolar mode.

5. The system of claim 1 wherein the controller is further configured to selectively connect different pairs of the radio frequency outputs in a bipolar mode in response to a configuration selection made through the user interface.

6. The system of claim 1 wherein the controller is further configured to deliver radio frequency energy from the radio frequency source to the radio frequency outputs in a plurality of successive time fields each having a period.

7. The system of claim 6 wherein the time fields have a duty cycle comprising a portion of the period when radio frequency energy is being delivered to the outputs and another portion of the period when radio frequency energy is not being delivered to the outputs.

8. The system of claim 7 wherein the controller is further configured to adjust the duty cycle in response to a configuration selection made through the user interface.

9. The system of claim 6 wherein at least one time field of the plurality of the successive time fields is monopolar for at least a portion of the period, and at least another time field of the successive time fields is bipolar for at least a portion of the period.

10. The system of claim 9 wherein the controller is configured to adjust a ratio of bipolar to monopolar time fields in response to a configuration selection made through the user interface.

11. The system of claim 9 wherein at least one time field is a combination monopolar/bipolar time field.

12. The system of claim 6 wherein the controller is further configured to adjust a length of at least one time field in response to a configuration selection made through the user interface.

13. The system of claim 1 wherein the radio frequency source is a constant voltage source.

14. The system of claim 1 wherein the radio frequency source is a variable voltage source.

15. The system of claim 14 wherein the controller is further configured to vary voltage amplitude in response to a configuration selection made through the user interface.

16. The system of claim 1 wherein the controller is further configured to adjust voltage phase angle of the RF source.

17. The system of claim 16 wherein the controller is further configured to adjust voltage phase angle of the radio frequency source in response to a configuration selection made through the user interface.

18. The system of claim 1 wherein the controller comprises a time division multiplexor.

19. The system of claim 1 wherein the radio frequency generator further comprises an electrode tool interface configured to detect an identifier of a radio frequency electrode tool connected to the interface, the controller being configured to adjust radio frequency energy delivery parameters to an radio frequency electrode tool based on the identifier detected by the interface.

20. The system of claim 19 further comprising a first radio frequency electrode tool having a first electrode configuration and second radio frequency electrode tool having a second electrode configuration different from the first electrode configuration, the first and second radio frequency electrode tools each comprising a connector adapted to connect to the radio frequency generator electrode tool interface, the connector of each tool comprising a unique identifier adapted to communicate with the radio frequency generator electrode tool interface.

21. The system of claim 1 further comprising a ground pad, the controller being configured to connect and disconnect the ground pad to a ground source in response to a configuration selection made through the user interface.

22. The system of claim 1 wherein each output comprises an output line, a return line and a resistance between output line and the return line.

23. The system of claim 22 wherein the resistance has a value that provides signal stability on the output during light load conditions at the output.

24. A radio frequency ablation system comprising:

a radio frequency generator;

a plurality of radio frequency electrodes;

a temperature sensor; and

a controller communicating with the temperature sensor to control an amount of energy delivered to the electrodes in a first portion of an energy delivery session irrespective of temperature sensed by the temperature sensor and in a second portion of the energy delivery session based on the temperature sensed by the temperature sensor.

25. The system of claim 24 wherein the controller is configured to cease energy delivery to the electrodes when a predetermined target temperature is sensed by the temperature sensor.

26. The system of claim 25 further comprising a user interface adapted to set the target temperature.

27. The system of claim 25 wherein the controller is further configured to cease the first portion of the energy delivery session when the temperature sensor reaches a threshold temperature that is a predetermined amount lower than the target temperature.

28. The system of claim 24 wherein the controller is configured to cease the first portion of the energy delivery session when temperature sensed by the temperature sensor reaches a threshold temperature.

29. The system of claim 28 further comprising a user interface adapted to set the threshold temperature.

30. The system of claim 24 wherein the controller is configured to independently control energy delivery to each electrode.

31. The system of claim 30 further comprising a temperature sensor associated with each electrode, the controller independently communicating with each temperature sensor in the delivering step to control the amount of energy delivered to the electrodes.

32. The system of claim 24 wherein the controller is configured to independently control energy to a pair of electrodes and at least one other electrode.

33. The system of claim 24 wherein the controller is configured to deliver radio frequency energy in a plurality of successive time fields each having a period and a duty cycle comprising a portion of the period when radio frequency energy is being delivered to the electrodes and another portion of the period when radio frequency energy is not being delivered to the electrodes.

34. The system of claim 33 wherein the controller is further configured to adjust the duty cycle based on monitored temperature.

35. The system of claim 24 wherein the controller is configured to compare temperature sensed by the temperature sensor to a target temperature and to adjust a power goal based on the comparison.

36. The system of claim 35 wherein the controller is further configured to compare the power goal to a power limit and to reset the power goal to the power limit if the power goal exceeds the power limit.

37. A radio frequency energy generation system for delivering radio frequency energy to a cardiac ablation catheter, comprising:

a radio frequency generator adapted to deliver radio frequency energy in both monopolar and bipolar modes to an ablation catheter, wherein the ablation catheter comprises an electrode array comprising at least one electrode;

an EKG monitoring unit adapted to monitor and map signals detected by the plurality of ablation catheters; and

an interface unit comprising an inductor which couples the radio frequency generator and EKG monitoring unit to filter radio frequency signals from EKG signals received by the EKG monitoring unit.

38. The system of claim 37 wherein the at least one electrode is adapted to monitor the temperature of atrial tissue adjacent the electrode, and wherein the generator generates radio frequency energy based on the temperature of the atrial tissue.

39. The system of claim 38 wherein the at least one electrode comprises a plurality of electrodes, and wherein the generator is adapted to independently monitor the temperature of atrial tissue measured by each of the plurality of electrodes, and wherein the radio frequency generator is adapted to generate and deliver radio frequency energy to each of the plurality of electrodes based on the independently monitored temperatures.

40. The system of claim 37 wherein the EKG monitoring unit comprises a plurality of inputs and an inductor associated with each input.

41. The system of claim 37 wherein the generator is adapted to deliver energy in a bipolar mode, a monopolar mode, and a combination of both bipolar and monopolar modes.

42. The system of claim 41 wherein the generator is adapted to deliver a combination of bipolar and monopolar radio frequency energy to the electrode array in bipolar to monopolar ratios of at least 4:

1, 2;

1, and 1;

1.

43. A method of delivering radio frequency ablation energy to a patient'"'"'s tissue comprising

delivering radio frequency energy to a plurality of electrodes to heat the patient'"'"'s tissue in first and second portions of an energy delivery session;

monitoring temperature of the patient'"'"'s tissue during the delivering step;

delivering radio frequency energy at a power level in the first portion of the energy delivery session, the power level being irrespective of monitored tissue temperature; and

controlling radio frequency energy delivered to the electrodes in the second portion of the energy delivery session based on monitored tissue temperature.

44. The method of claim 43 further comprising ceasing energy delivery when a predetermined target tissue temperature is reached.

45. The method of claim 44 further comprising setting the target tissue temperature.

46. The method of claim 44 further comprising ceasing the first portion of the energy delivery session when monitored tissue temperature reaches a threshold tissue temperature that is a predetermined amount lower than the target tissue temperature.

47. The method of claim 43 further comprising ceasing the first portion of the energy delivery session when a threshold tissue temperature is reached.

48. The method of claim 47 further comprising setting the threshold tissue temperature.

49. The method of claim 43 wherein at least one of the controlling steps comprises independently controlling energy delivery to each electrode.

50. The method of claim 43 wherein at least one of the controlling steps comprises independently controlling energy delivery to a pair of electrodes and to at least one other electrode.

51. The method of claim 43 wherein the delivering step comprises delivering radio frequency energy in a plurality of successive time fields each having a period and a duty cycle comprising a portion of the period when radio frequency energy is being delivered to the electrodes and another portion of the period when radio frequency energy is not being delivered to the electrodes.

52. The method of claim 51 wherein at least one of the controlling steps comprises adjusting the duty cycle.

53. The method of claim 43 wherein the step of controlling radio frequency energy delivered to the electrodes in the second portion of the energy delivery session comprises comparing a monitored temperature to a target temperature and adjusting a power goal.

54. The method of claim 53 wherein the delivering step comprises comparing the power goal to a power limit and resetting the power goal to the power limit if the power goal exceeds the power limit.

55. The method of claim 43 wherein the patient'"'"'s tissue comprises heart tissue, prostate tissue, brain tissue, gall bladder tissue, uterine tissue, or tumor tissue.