Impedance-based cardiac therapy planning method with a remote surgical navigation system

• US 8,273,081 B2
• Filed: 09/10/2007
• Issued: 09/25/2012
• Est. Priority Date: 09/08/2006
• Status: Active Grant

• Current Assignee: Stereotaxis, Inc.
• Original Assignee: Stereotaxis, Inc.
• Inventors: Viswanathan, Raju R.
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): HUPCZEY, JR, RONALD JAMES
• Application Number:
  US11/852,950
• Publication Number:
  US 20080065061A1
• Time in Patent Office: 1,842 Days
• Field of Search: 606 32- 50, 128/898
• US Class Current: 606/32
• 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 2018/00577 Ablation
• 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 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• 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 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: A61B 5/283 Invasive

Abstract

A method is disclosed for planning the treatment of cardiac arrhythmias by RF ablation with a remote navigation system, including the identification of ablation lines around the pulmonary veins ostia—atrial junctions based on impedance measurements. When used by itself or in conjunction with electro-anatomical approaches, the impedance method therein disclosed enables safe and effective arrhythmia treatment.

Claims

1. A method of defining ablation lines in the left atrium of the heart, comprising:

i) performing impedance mapping of the left atrium and a pair of pulmonary veins;

ii) for each pulmonary vein, defining an impedance threshold value corresponding to the pulmonary vein ostium;

iii) defining iso-impedance contours for each of the veins based on corresponding impedance threshold ii) and impedance mapping i);

iv) determining whether the two iso-impedance contours iii) are a) crossing;

b) tangent;

or c) neither;

v) increasing or decreasing the two respective impedance contour values by a predetermined amount if the contours are crossing, or not, respectively, and defining corresponding iso-impedance contours;

vi) iterating over steps iv) and v) until the two contours are tangent, and defining an associated single iso-impedance contour; and

vii) retaining the corresponding iso-impedance contour as a pulmonary vein pair ablation line.

2. The method of claim 1, further comprising decreasing the contour impedance of the single contour of step vi) by a second predetermined amount and retaining the corresponding iso-impedance contour as a pulmonary vein pair ablation line.

3. The method of claim 1, further comprising using imaging to guide the selection of the ablation lines.

4. The method of claim 1, further comprising performing a plurality of electrical activity measurements within the left atrium to guide the selection of the ablation lines.