Dynamic adaptive respiration compensation with automatic gain control

• US 20150366512A1
• Filed: 07/16/2015
• Published: 12/24/2015
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Original Assignee: St. Jude Medical (Abbott Laboratories Incorporated)
• Inventors: Koyrakh, Lev A., Voth, Eric J., Hauck, John A., Schweitzer, Jeffrey A.
• Granted Patent: US 10,561,371 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0044 for the heart
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/063 using impedance measurements
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: H04L 25/0278 Arrangements for impedance matching

Abstract

A system for determining a location of an electrode of a medical device (e.g., a catheter) in a body of a patient includes a localization block for producing an uncompensated electrode location, a motion compensation block for producing a compensation signal (i.e., for respiration, cardiac, etc.), and a mechanism for subtracting the compensation signal from the uncompensated electrode location. The result is a corrected electrode location substantially free of respiration and cardiac artifacts. The motion compensation block includes a dynamic adaptation feature which accounts for changes in a patient'"'"'s respiration patterns as well as intentional movements of the medical device to different locations within the patient'"'"'s body. The system further includes an automatic compensation gain control which suppresses compensation when certain conditions, such as noise or sudden patch impedance changes, are detected.

Claims

1-7. -7. (canceled)

8. A system for determining a motion compensated location of an electrode of a medical device within a body of a patient, comprising:

a main control unit including (i) a localization block configured to produce an uncompensated electrode location;

(ii) a compensation block configured to generate a compensation signal; and

(iii) a mechanism to subtract said compensation signal from said uncompensated electrode location to output a motion compensated electrode location;

said compensation block being configured to (i) mean-adjust patch electrode impedance data associated with body surface electrodes and electrode location data associated with said electrode;

(ii) acquire a set of weights by equating the product of said set of weights and said mean-adjusted patch impedance data with said mean-adjusted electrode location data;

(iii) to further mean-adjust patch impedance and electrode location data for further time periods to produce a plurality of acquired sets of weights;

(iv) to update a reference set of weights, based on a learning parameter, for each successive acquired sets of weights, wherein said learning parameter is determined in accordance with a distance between successive, acquired sets of weights; and

(v) to determine said compensation signal based on said updated reference set of weights and patch electrode impedance data.

9. A system for determining a motion compensated location of an electrode of a medical device within a body of a patient, comprising:

a main control unit including (i) a localization block configured to produce an uncompensated electrode location;

(ii) a compensation block configured to generate a compensation signal; and

(iii) a mechanism to subtract said compensation signal from said uncompensated electrode location to output a motion compensated electrode location;

said compensation block being configured to (i) mean-adjust patch electrode impedance data associated with body surface electrodes and electrode location data associated with said electrode;

(ii) acquire a set of weights such that a linear combination of the product of said set of weights and said mean-adjusted patch impedance data correspond to said mean-adjusted electrode location data;

(iii) to further mean-adjust patch impedance and electrode location data for further time periods to produce a plurality of acquired sets of weights;

(iv) to update a reference set of weights, based on a learning parameter, for each successive acquired sets of weights, wherein said learning parameter is determined in accordance with a distance between successive, acquired sets of weights; and

(v) to determine said compensation signal based on said updated reference set of weights and patch electrode impedance data.

10. The system of claim 9 wherein said mean-adjusted patch and electrode data are in matrix form, said compensation block being further configured (i) to perform singular value decomposition of the mean-adjusted patch data;

(ii) to obtain the pseudo-inverse of said mean-adjusted patch data matrix and to apply regularization; and

(iii) to determine said acquired set of weights in accordance with the product of said pseudo-inverse mean-adjusted patch data matrix and said electrode location data matrix.

11. The system of claim 9 wherein compensation block is further configured to sum said reference set of weights with the product of said learning parameter and a difference between a most-recently acquired set of weights and said reference set of weights.

12. The system of claim 11 wherein said compensation block is further configured to vary said learning parameter in accordance with a distance between successive, acquired sets of weights.

13. The system of claim 9 wherein said compensation block is further configured to compute said compensation signal as a function of a gain parameter.

14. The system of claim 13 wherein said compensation block is further configured to determine (i) a moving average of said compensation signal;

(ii) an average deviation of said compensation signal from said moving average; and

(iii) a value of said gain parameter as a function of a ratio of said average deviation and a current deviation between the current compensation signal and said moving average.

15. The system of claim 9 wherein said electrode is a first electrode and said motion compensated electrode location is a compensated first electrode location having associated therewith a coordinate within a reference coordinate system, said localization block being configured to determine an uncompensated second electrode location associated with a second electrode, said compensation block being further configured to apply said compensation signal to said uncompensated second electrode location to produce a motion compensated second electrode location when said uncompensated second electrode location matches said coordinate within a predetermined range.

16. The system of claim 9 wherein said uncompensated electrode location includes one of a position and orientation (P&

O) in a reference coordinate system, wherein said compensation block is further configured to acquire a respective set of weights for each selected axis in the reference coordinate system.

17. The system of claim 9 wherein said compensation block is further configured to acquire said set of weights involving principal component analysis (PCA).

18. The system of claim 9 wherein said compensation block is configured to exponentially reduce the learning parameter when the distance between successive, acquired sets of weights exceeds a threshold to thereby suppress learning parameter adaptation.

19. The system of claim 9 wherein said compensation block is further configured to acquire (i) said patch electrode impedance data using associated body surface electrodes and (ii) said electrode location data using said electrode of said medical device.

20. The system of claim 9 wherein said main control unit is configured to generate a visual representation of the medical device on a display based on the motion compensated electrode location.

21. The system of claim 9 wherein said compensation signal corresponds to motion artifacts associated with said uncompensated electrode location and wherein said motion compensation signal is configured to reduce such motion artifacts associated with said uncompensated electrode location.

22. The system of claim 21 wherein said motion artifacts comprise at least one of respiration-induced motion artifacts and cardiac motion artifacts.

23. A system for determining a motion compensated location of an electrode of a medical device within a body of a patient, comprising:

a main electronic control unit including;

a localization block configured to produce an uncompensated electrode location, said localization block being further configured to acquire patch electrode impedance data using associated body surface electrodes and electrode location data using said electrode of said medical device;

a compensation block configured to;

mean-adjust said patch electrode impedance data associated with body surface electrodes and electrode location data associated with said electrode;

determine an acquired set of weights such that a linear combination of the product of said weights and said mean-adjusted patch impedance data correspond to said mean-adjusted electrode location data;

repeatedly acquire said patch electrode impedance data and said electrode location data, mean-adjust said patch electrode impedance data and said electrode location data, and determine said acquired set of weight for a plurality of different time periods and producing a plurality of acquired sets of weights, and as each successive acquired sets of weights is determined;

(i) determining a learning parameter based on a distance between successive, acquired sets of weights,

(ii) updating a reference set of weights based on said determined learning parameter;

determine a compensation signal based on said updated reference set of weights and patch electrode impedance data, wherein the compensation signal corresponds to motion artifacts associated with an uncompensated electrode location and wherein the compensation signal is configured to reduce such motion artifacts associated with the uncompensated electrode location;

a mechanism configured to determine said motion compensated electrode location using said uncompensated electrode location and said compensation signal; and

means for generating a visual representation of the medical device on a display based on said motion compensated electrode location.

24. The system of claim 23 wherein said motion compensated electrode location includes one of a position and orientation (P&

O) in a reference coordinate system, said main electronic control unit being further configured to select one or more axes for compensation wherein said compensation block determines a respective set of weights for each selected axis.

25. The system of claim 23 wherein said compensation block is configured to determine said set of weights using principal component analysis (PCA).

26. The system of claim 23 wherein said mean-adjusted patch and electrode data are in matrix form, said compensation block being further configured (i) to perform singular value decomposition of the mean-adjusted patch data matrix;

(ii) to obtain the pseudo-inverse of said mean-adjusted patch data matrix and to apply regularization; and

(iii) to determine said set of weights in accordance with the product of said pseudo-inverse mean-adjusted patch data matrix and said electrode location data matrix.

27. The system of claim 23 wherein compensation block is further configured to determine a difference between a most-recent acquired set of weights and the current reference set of weights, determine a product of the learning parameter and the difference, and sum the current reference set of weights and the product.

28. The system of claim 27 wherein said learning parameter is equal to or greater than zero and equal to or less than one.

29. The system of claim 27 wherein said compensation block is further configured to vary said learning parameter in accordance with a distance between successive, acquired sets of weights.

30. The system of claim 29 wherein said compensation block is further configured to vary the learning parameter by exponentially reducing said learning parameter as a function of said distance between successive, acquired sets of weights.

31. The system of claim 23 wherein said compensation block is further configured to determine said compensation signal by automatically controlling a gain parameter.

32. The system of claim 31 wherein said compensation block is configured to set said gain parameter to a default value of 1.

33. The system of claim 32 wherein said compensation block is further configured to determine (i) a moving average of said compensation signal;

(ii) an average deviation of said compensation signal from said moving average;

(iii) a current deviation between a current value of the compensation signal and the moving average; and

(iv) reduce said default value of said gain parameter in accordance with a ratio between said average deviation and said current deviation when said current deviation exceeds a deviation threshold.

34. The system of claim 33 wherein said motion compensated electrode location includes one of a position and orientation (P&

O) in a reference coordinate system, said main electronic control unit being further configured to select one or more axes in the coordinate system for compensation, said gain parameter having respective values for each one of said selected axes.

35. The system of claim 23 wherein said electrode is a first electrode and said motion compensated electrode location is a motion compensated first electrode location having associated therewith a coordinate within a reference coordinate system, said localization block being configured to determine an uncompensated second electrode location associated with a second electrode, said compensation block being further configured to apply said compensation signal to said uncompensated second electrode location to produce a motion compensated second electrode location when said uncompensated second electrode location matches said coordinate within a predetermined range.