Apparatus and method for ablating tissue

• US 20050251125A1
• Filed: 06/28/2004
• Published: 11/10/2005
• Est. Priority Date: 09/21/1998
• Status: Abandoned Application

• Current Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Original Assignee: Epicor Medical, Inc. (Abbott Laboratories Incorporated)
• Inventors: Vaska, Matthias, Richman, Roxanne L., Anderson, Scott C., Gallup, David A., Podmore, Jonathan L., Pless, Benjamin, Ciciarelli, Timothy, Ulstad, Jack E. Jr., Crowe, John E.
• Application Number:
  US10/879,975
• Publication Number:
  US 20050251125A1
• Time in Patent Office: Days
• US Class Current: 606/27
• CPC Class Codes: A61B 17/22012 in direct contact with, or very close to, the obstruction or concrement for removing obstructions in blood vessels by laser A61B18/245
• CPC Class Codes: A61B 17/2202 the ultrasound transducer being inside patient's body at the distal end of the catheter
• CPC Class Codes: A61B 18/00 Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• 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 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/00252 for by-pass connections, i.e. connections from heart chamber to blood vessel or from blood vessel to blood vessel
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/22077 with a part piercing the tissue A61B2017/22044 takes precedence
• CPC Class Codes: A61B 2017/3419 Sealing means between cannula and body
• CPC Class Codes: A61B 2018/00023 closed, i.e. without wound contact by the fluid
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00232 having an irregular shape
• CPC Class Codes: A61B 2018/00261 arranged in a line
• CPC Class Codes: A61B 2018/00285 Balloons
• CPC Class Codes: A61B 2018/00291 : using suction
• CPC Class Codes: A61B 2018/00351 : Heart
• CPC Class Codes: A61B 2018/00363 : Epicardium
• CPC Class Codes: A61B 2018/00392 : Transmyocardial revascularisation
• 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 2018/00797 : measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00839 : Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/142 : at least partly surrounding the target, e.g. concave, curved or in the form of a cave
• 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 2090/3614 : using optical fibre
• CPC Class Codes: A61B 2090/3782 : transmitter or receiver in catheter or minimal invasive instrument
• CPC Class Codes: A61B 2090/395 : with marking agent for marking skin or other tissue
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61B 34/20 : Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/287 : Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61N 1/06 : for high-frequency therapy
• CPC Class Codes: A61N 1/3629 : in combination with non-electric therapy
• CPC Class Codes: A61N 2007/0065 : Concave transducers
• CPC Class Codes: A61N 2007/0078 : with multiple treatment transducers
• CPC Class Codes: A61N 2007/027 : with multiple foci created simultaneously
• CPC Class Codes: A61N 7/02 : Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

A control system alters one or more characteristics of an ablating element to ablate tissue. In one aspect, the control system delivers energy nearer to the surface of the tissue by changing the frequency or power. In another aspect, the ablating element delivers focused ultrasound which is focused in at least one dimension. The ablating device may also have a number of ablating elements with different characteristics such as focal length.

Claims

1. A method of ablating cardiac tissue, comprising the steps of:

providing an ablating device having an ultrasonic transducer, the device emitting focused ultrasound which is focused in at least one dimension;

positioning the ablating device in contact with cardiac tissue; and

activating the ultrasonic transducer to direct the focused ultrasound into the cardiac tissue.

2. The method of claim 1, wherein:

the activating step is carried out to electrically isolate one part of the heart from another part of the heart.

3. The method of claim 1, wherein:

the providing and activating steps are carried out with the focused ultrasound being focused along a focal axis and diverging when viewed perpendicular to the focal axis.

4. The method of claim 1, further comprising the step of:

moving a focus of the focused ultrasound relative to the cardiac tissue.

5. The method of claim 4, wherein:

the moving step is carried out to move the focus closer to a near surface of the cardiac tissue.

6. The method of claim 1, wherein:

the providing step is carried out so that at least 90% of the focused ultrasound passes within a focus area defined by a focal length of about 2 to 20 mm and an angle of about 10 to 170 degrees when viewed along a focal axis.

7. The method of claim 1, wherein:

the providing step is carried out with the focused energy being emitted by a concave surface.

8. The method of claim 1, wherein:

the providing step is carried out with the concave surface being attached to a piezoelectric transducer.

9. The method of claim 7, wherein:

the providing step is carried out with the concave surface having a focal length of 2-20 mm.

10. The method of claim 9, wherein:

the providing step is carried out with the focused energy having a focal length of 2 to 12 mm.

11. The method of claim 1, wherein:

the activating step is carried out by activating the ultrasonic transducer for a first period of time at a first frequency and a second period of time at a second frequency which is different than the first frequency and occurs after the first period of time.

12. The method of claim 11, wherein:

the activating step is carried out with the first frequency being lower than the second frequency.

13. The method of claim 12, wherein:

the activating step is carried out with the first period of time being shorter than the second period of time.

14. The method of claim 13, wherein:

the activating step is carried out with the first period of time being less than 1 second.

15. The method of claim 11, wherein:

the activating step is carried out with the ultrasonic transducer being activated at the first frequency for a number of discrete time periods.

16. The method of claim 15, wherein:

the activating step is carried out with the ultrasonic transducer being inactive for 3-8 seconds between each of the number of discrete time periods.

17. The method of claim 1, further comprising the step of:

approximating a temperature of the tissue.

18. The method of claim 1, further comprising the step of:

assessing the adequacy of contact between the device and the tissue.

19. The method of claim 1, further comprising the step of:

determining a tissue layer thickness using the ultrasound transducer.

20. The method of claim 19, wherein:

the determining step is carried out with the tissue layer being a tissue layer between a near surface and a far surface.

21. The method of claim 19, wherein:

the determining step is carried out with the tissue layer being a fat layer which lies over a muscle layer.

22. The method of claim 1, further comprising the step of:

measuring a blood flow velocity with the ultrasonic transducer.

23. The method of claim 1, further comprising the step of:

moving the a focus of the focused ultrasound relative to the tissue.

24. The method of claim 23, wherein:

the moving step is carried out with the ultrasonic transducer being tilted.

25. The method of claim 1, wherein:

the providing step is carried out with the ablating device having a number of ultrasonic transducers.

26-62. -62. (canceled)

63. A method of ablating cardiac tissue, comprising the steps of:

providing an ablating device having an ultrasonic transducer;

positioning the ablating device in contact with a tissue structure to be ablated; and

activating the ultrasonic transducer for a first period of time at a first power to produce ultrasonic energy which is directed at the tissue structure, the activating step also being carried out with the ultrasonic transducer being activated for a second period of time at a second power which is different than the first power.

64. The method of claim 63, wherein:

the activating step is carried out with the ultrasonic transducer being activated at different frequencies during the first and second periods of time.

65. The method of claim 63, wherein:

the activating step is carried out with the first period of time being smaller than the second period of time.

66. The method of claim 65, wherein:

the activating step is carried out with the first power being higher than the second power.

67. A device for ablating tissue, comprising:

a body having a longitudinal axis and a contact surface configured to be positioned adjacent tissue to be ablated;

a first transducer coupled to the body;

a second transducer coupled to the body and spaced apart from the first transducer by a space; and

wherein at least one of the first and second transducers directs ultrasound energy to tissue lying beneath the space between the first and second transducers.

68. The device of claim 67, wherein:

both the first and second transducers direct ultrasound energy to tissue lying beneath the space between the first and second transducers.

69. The device of claim 67, wherein:

a flexible membrane extends over the at least one of the first and second transducers, the flexible membrane conforming to the surface of the tissue and being filled with a substance which transmits the ultrasound energy from the transducer to the tissue.

70. The device of claim 67, wherein:

the first and second transducers have the same shape, the first and second transducers each directing ultrasound energy to tissue beneath the first and second transducers, respectively, and the first and second transducers also directing ultrasound energy to tissue lying beneath the space between the first and second transducers.

71. A device for ablating cardiac tissue, comprising:

a body having a longitudinal axis and a contact surface configured to be positioned adjacent tissue to be ablated;

a first transducer coupled to the body;

a second transducer coupled to the body and spaced apart from the first transducer by a space, wherein the first and second transducers each emit ultrasound energy to the tissue to be ablated; and

means for changing the direction of the ultrasound energy from the first transducer toward tissue beneath the gap between the first and second transducers.

72. The device of claim 71, further comprising;

an inflatable membrane positioned beneath the first transducer to form the contact surface below the first transducer, the transducer moving upon inflation of the balloon.

73-114. -114. (canceled)