RESPIRATORY EFFECT REDUCTION IN CATHETER POSITION SENSING

• US 20120172712A1
• Filed: 12/29/2010
• Published: 07/05/2012
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Biosense Webster Israel Ltd. (Johnson & Johnson)
• Original Assignee: Biosense Webster Israel Ltd. (Johnson & Johnson)
• Inventors: Bar-Tal, Meir
• Granted Patent: US 9,414,770 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2017/00699 correcting for movement caused by respiration, e.g. by triggering
• CPC Class Codes: A61B 2034/2046 Tracking techniques
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2053 Tracking an applied voltage gradient
• 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 5/062 using magnetic field
• CPC Class Codes: A61B 5/063 using impedance measurements
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence

Abstract

A method, including positioning body-electrodes in galvanic contact with a body of a patient and locating a probe in the body of the patient. The method further includes tracking positions of the probe during respiration of the patient and determining indications related to impedances between the body-electrodes during the respiration. The method also includes calculating a function relating the positions of the probe to the indications, and applying the function to identify end-expirium points of the respiration based on subsequent indications related to the impedances.

Claims

1. A method, comprising:

positioning body-electrodes in galvanic contact with a body of a patient;

locating a probe in the body of the patient;

tracking positions of the probe during respiration of the patient;

determining indications related to impedances between the body-electrodes during the respiration;

calculating a function relating the positions of the probe to the indications; and

applying the function to identify end-expirium points of the respiration based on subsequent indications related to the impedances.

2. The method according to claim 1, wherein identifying the end-expirium points comprises evaluating that the function is less than a predetermined threshold.

3. The method according to claim 1, wherein tracking the positions of the probe comprises determining the positions using an electromagnetic tracking system.

4. The method according to claim 1, wherein tracking the positions of the probe comprises computing the positions in response to currents between the probe and the body-electrodes.

5. The method according to claim 1, wherein determining the indications comprises measuring respective currents between the probe and the body-electrodes.

6. The method according to claim 1, wherein determining the indications comprises formulating a matrix relating the impedances between the body-electrodes to the positions of the probe.

7. The method according to claim 6, wherein formulating the matrix comprises determining a direction of the respiration.

8. The method according to claim 7, and comprising determining the end-experium points for the respiration in response to the matrix and the direction.

9. The method according to claim 7, and comprising determining the end-experium points for the respiration in response to a rate of change of the indications, the matrix, and the direction.

10. Apparatus, comprising:

body-electrodes which are positioned in galvanic contact with a body of a patient;

a probe located in the body of the patient; and

a processor, which is configured to;

track positions of the probe during respiration of the patient,

determine indications related to impedances between the body-electrodes during the respiration,

calculate a function relating the positions of the probe to the indications, and

apply the function to identify end-expirium points of the respiration based on subsequent indications related to the impedances.

11. The apparatus according to claim 10, wherein identifying the end-expirium points comprises evaluating that the function is less than a predetermined threshold.

12. The apparatus according to claim 10, wherein tracking the positions of the probe comprises determining the positions using an electromagnetic tracking system.

13. The apparatus according to claim 10, wherein tracking the positions of the probe comprises computing the positions in response to currents between the probe and the body-electrodes.

14. The apparatus according to claim 10, wherein determining the indications comprises measuring respective currents between the probe and the body-electrodes.

15. The apparatus according to claim 11, wherein determining the indications comprises formulating a matrix relating the impedances between the body-electrodes to the positions of the probe.

16. The apparatus according to claim 15, wherein formulating the matrix comprises determining a direction of the respiration.

17. The apparatus according to claim 16, wherein the processor is configured to determine the end-experium points for the respiration in response to the matrix and the direction.

18. The apparatus according to claim 16, wherein the processor is configured to determine the end-experium points for the respiration in response to a rate of change of the indications, the matrix, and the direction.