Apparatus and method for assessing transmurality of a tissue ablation

• US 7,192,427 B2
• Filed: 02/19/2003
• Issued: 03/20/2007
• Est. Priority Date: 02/19/2002
• Status: Expired due to Fees

• Current Assignee: Maquet Cardiovascular LLC (Getinge AB)
• Original Assignee: AFX, Inc. (Boston Scientific Corporation)
• Inventors: Nguyen, Hiep, Berube, Dany, Chapelon, Pierre-Antoine, Kallel, Faouzi
• Primary Examiner(s): Cohen; Lee S.
• Application Number:
  US10/369,887
• Publication Number:
  US 20030220639A1
• Time in Patent Office: 1,490 Days
• Field of Search: 606/33, 606/34, 606/41, 600/547
• 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 method of assessing the transmurality of an ablation lesion formed in targeted biological tissue by an instrument that radiates electrical ablative energy, said method comprising:

operably positioning a first element relative to a first surface of the targeted tissue for transmitting an electrical signal therein;

operably positioning a second element relative to a second tissue surface of the targeted tissue spaced away from the first element for receiving electrical signal from within the tissue transmitted from the first element;

applying ablative energy to the targeted tissue through the instrument operatively separate from the first and second elements to form the ablation lesion therein;

measuring a tissue characteristic related to at least one of conduction time, conduction velocity, phase angle, and impedance in response to the electrical signal received at the second element; and

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

2. The method of claim 1, wherein

the step of evaluating comprises filtering the tissue characteristic measurement to remove undesirable signals.

3. The method of claim 2, wherein

evaluating the tissue characteristic measurement is performed relative to a normalized measurement.

4. The method of claim 1, wherein

evaluating further comprises providing a least mean square estimation of change of the tissue characteristic measurement during formation of the ablation lesion.

5. The method of claim 1, wherein

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

6. The method of claim 1, wherein the first element supplies to the targeted tissue a high frequency electrical signal distinct from the radiated electrical ablative energy;

the second element receives a high frequency electrical signal from within the tissue supplied by the first element; and

measuring includes comparing the supplied and received high frequency electrical signals relative to at least one of conduction time, conduction velocity, phase angle and impedance for assessing the transmurality of the ablation lesion.