Apparatus and method for assessing transmuarlity of a tissue ablation

• US 20030220639A1
• Filed: 02/19/2003
• Published: 11/27/2003
• Est. Priority Date: 02/19/2002
• Status: Active Grant

• Current Assignee: Maquet Cardiovascular LLC (Getinge AB)
• Original Assignee: AFX, Inc. (Boston Scientific Corporation)
• Inventors: Nguyen, Hiep, Berube, Dany, Chapelon, Pierre-Antoine, Kallel, Faouzi
• Granted Patent: US 7,192,427 B2
• Time in Patent Office: Days
• US Class Current: 606/33
• 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 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance

Abstract

An instrument is provided to assess the transmurality of an ablation lesion from a first surface of a targeted biological tissue to an opposed second surface thereof. The instrument includes at least a first electrode operably attached to an ablation instrument adapted to engage a tissue first surface, and at least a second electrode adapted to engage a tissue second surface, the at least second electrode positioned generally opposed to the at least first electrode. Alternatively, the at least second electrode may be adapted to be placed within a chamber of an organ. These electrodes each measure at least one of conduction time, conduction velocity, phase angle, and impedance through at least a portion of the targeted tissue to determine the transmurality of the ablation lesion.

Claims

1. A device for assessing the transmurality of an elongated ablation lesion from a first surface of a targeted biological tissue to an opposed second surface thereof comprising:

a first of at least two sensing elements operably placed proximate the ablation lesion, the first element placed in contact with a first surface of the biological tissue; and

a second of at least two sensing elements operably placed proximate the ablation lesion, the second sensing element placed proximate to a second surface of the biological tissue,

wherein the at least two sensing elements are adapted to transmit or receive electrical signals to measure at least one of conduction time, conduction velocity, phase angle, and impedance through at least a portion of the targeted biological tissue, to determine the transmurality of an ablation lesion created therein.

2. The device according to claim 1, wherein

the second element is in contact with the second tissue surface.

3. The device according to claim 2, wherein

the second element is elongated to span at least the length of the ablation lesion.

4. The device according to claim 3, wherein

the second element comprises a plurality of spaced apart sensing elements.

5. The device according to claim 4, wherein

each of the plurality of sensing elements are individually selectable to receive electrical signals to measure at least one of conduction time, conduction velocity, phase angle, and impedance through at least a portion of the targeted biological tissue.

6. The device according to claim 1, wherein

the first electrode is adapted to transmit a first signal to the first tissue surface and the second electrode is adapted to receive a second signal responsive to the first signal.

7. The device according to claim 1 further comprising an elongated member upon which the second electrode is operably placed, wherein

the second electrode is operably positioned within the chamber of an organ.

8. The device according to claim 7, wherein

the elongated member is flexible.

9. The device according to claim 7, wherein

elongated member is malleable.

10. The device according to claim 7, wherein

elongated member is rigid.

11. The device according to claim 7, wherein

a distal tip of the elongated member is adapted to pierce and pass through the tissue.

12. The device according to claim 1, wherein

the first electrode is operably attached to an ablation instrument.

13. The device according to claim 12, wherein

the ablation instrument comprises an antenna assembly from which ablative energy is emitted.

14. The device according to claim 13, wherein

the ablation instrument further comprises a guiding assembly having at least one lumen therethrough, the antenna assembly adapted to translate within the a first of the at least one lumen.

15. The device according to claim 14, wherein

the first sensing element comprises a plurality of spaced apart sensing elements operably attached to an outer surface of the guiding assembly.

16. A method of assessing the transmurality of an elongated ablation lesion from a first surface of a targeted biological tissue to an opposed second surface thereof, said method comprising

providing a first and a second of at least two sensing elements, the first element operably positioned in contact with a first tissue surface proximate an ablation lesion and adapted to transmit a first signal therein, the second element operably positioned proximate a second tissue surface and adapted to receive a second signal responsive to the first signal;

applying ablative power to the targeted tissue;

measuring a tissue characteristic related to at least one of conduction time, conduction velocity, phase angle, and impedance through at least a portion of the targeted biological tissue; and

evaluating the tissue characteristic measurement to assess the transmurality of the ablation lesion being created therein.

17. The method of claim 16, wherein

the step of evaluating comprises the step of filtering the tissue characteristic measurement whereby undesirable signals are removed.

18. The method of claim 17, wherein

the step of evaluating comprises an initial step of normalizing whereby the tissue characteristic measurement is a measurement relative to a normalized measurement.

19. The method of claim 18, wherein

the step of evaluating further comprises providing a least mean square estimation of the slope of the tissue characteristic measurement whereby the measurement is enhanced.

20. The method of claim 19, wherein

the steps of applying, measuring and evaluating are repeated until the ablation lesion is transmural.