Methods and apparatus for enhanced fiducial point determination and non-invasive hemodynamic parameter determination

• US 20080234594A1
• Filed: 08/21/2007
• Published: 09/25/2008
• Est. Priority Date: 03/23/2007
• Status: Active Grant

• Current Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation)
• Original Assignee: FUJIFILM SonoSite, Inc. (Fujifilm Holdings Corporation)
• Inventors: Brooks, Donald J., Malecha, Jeremy
• Granted Patent: US 8,290,577 B2
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/683 Means for maintaining contact with the body A61B5/6802 takes precedence
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

Methods and apparatus for utilizing multiple sources of physiologic data to enhance measurement robustness and accuracy. In one embodiment, phonocardiography or “heart sounds” data is used in combination with one or more other techniques (for example, impedance cardiography or ICG waveforms, and/or electrocardiography or ECG waveforms) to provide more accurate and robust physiological and/or hemodynamic assessment of living subjects. In one variant, the aforementioned methods and apparatus are used to improve ICG fiducial point (e.g., B, C and X point) detection and identification accuracy. Moreover, the new ICG fiducial points that may be clinically important may be identified using the disclosed methods and apparatus. In a further aspect, the invention discloses methods and apparatus for utilization of ICG and/or ECG waveform information to improve the identification and characterization of heart sounds (such as e.g., S1, S2, S3, or S4 heart sounds), murmurs, and other such artifacts or phenomena.

Claims

1. A method of assessing cardiac function within a living subject, comprising:

obtaining;

(i) acoustic information relating to the cardiac system of said subject;

(ii) electrocardiographic (ECG) information relating to said subject; and

(iii) impedance cardiographic (ICG) information relating to said subject; and

utilizing said acoustic, ECG and ICG information substantially in concert to assess cardiac function.

2. The method of claim 1, wherein said act of obtaining acoustic and ECG information are utilized to improve ICG fiducial point detection in said obtained ICG information.

3. The method of claim 2, further comprising:

confirming the timing of cardiac sounds within said obtained acoustic information utilizing at least in part a portion of said obtained ECG information; and

detecting one or more ICG fiducial points utilizing at least in part the confirmed timing within said obtained acoustic information.

4. The method of claim 3, wherein said cardiac sounds comprise S1 and S2 heart sounds.

5. The method of claim 4, wherein said one or more ICG fiducial points comprises a “

B”

point and a “

X”

point in said obtained ICG information.

6. The method of claim 3, wherein said portion of said ECG information comprises an “

R”

point reference.

7. The method of claim 1, wherein said acoustic and ECG information are utilized to improve classification of a plurality of ICG waveforms.

8. The method of claim 1, wherein said obtained ECG and ICG information are utilized to improve the characterization of said acoustic information.

9. Sensor apparatus for use in determining cardiac function of a living subject, comprising:

a substantially unitary base element;

a plurality of terminals; and

an acoustic receptor device;

wherein said plurality of terminals are utilized in the communication of electrocardiographic and impedance cardiographic information of said living subject to a processing device.

10. The sensor apparatus of claim 9, wherein said substantially unitary base element and said plurality of terminals are of low cost thereby rendering said sensor apparatus disposable.

11. The sensor apparatus of claim 10, further comprising a chamber, said chamber adapted to couple acoustic emissions from said living subject to said acoustic receptor device.

12. The sensor apparatus of claim 11, wherein said acoustic receptor device comprises a piezoelectric device.

13. The sensor apparatus of claim 11, wherein said acoustic receptor device comprises a piezoresistive device.

14. The sensor apparatus of claim 9, further comprising one or more signal line(s), wherein said plurality of terminals and said acoustic receptor device utilize the same of said one or more signal line(s).

15. The sensor apparatus of claim 9, wherein said acoustic receptor device is removable and is adapted to be received in a reception apparatus within said substantially unitary base element.

16. The sensor apparatus of claim 15, wherein said acoustic receptor device is adapted for wireless transmission of acoustic information.

17. The sensor apparatus of claim 9, wherein said acoustic receptor device comprises an electromagnetic diaphragm.

18. The sensor apparatus of claim 17, wherein said electromagnetic diaphragm further comprises:

a substantially conductive coating disposed on a surface to form a coated surface; and

a voltage-charged conductor located behind said coated surface.

19. Hemodynamic assessment apparatus for assessing hemodynamic properties associated with the cardiovascular system of a living subject, comprising:

one or more sensor apparatus, each one of said one or more sensor apparatus comprising a plurality of terminals and at least one of said one or more sensor apparatus comprising an acoustic receptor device;

a current source adapted to provide a predetermined current through the thoracic cavity of said living subject via said one or more sensor apparatus; and

a signal processing device adapted to analyze the signals obtained from said one or more sensor apparatus.

20. The hemodynamic assessment apparatus of claim 19, wherein said signal processing device is adapted to process said signals to derive:

(i) acoustic information;

(ii) electrocardiographic (ECG) information; and

(iii) impedance cardiographic (ICG) information.

21. The hemodynamic assessment apparatus of claim 20, further comprising one or more signal line(s), wherein said plurality of terminals and said acoustic receptor device utilize the same of said one or more signal line(s).

22. The hemodynamic assessment apparatus of claim 21, further comprising a single electrical interface, said single electrical interface connecting said one or more signal line(s) to individual ones of said one or more sensor apparatus.

23. The hemodynamic assessment apparatus of claim 19, further comprising a computer readable medium comprising a plurality of computer executable instructions, said plurality of computer executable instructions, when executed by said signal processing device performing the method comprising:

obtaining;

(i) acoustic information relating to the cardiac system of said subject;

(ii) electrocardiographic (ECG) information relating to said subject; and

(iii) impedance cardiographic (ICG) information relating to said subject; and

utilizing said acoustic, ECG and ICG information substantially in concert to assess cardiac function.

24. A computer readable medium comprising a plurality of computer executable instructions, said plurality of computer executable instructions, when executed by a processing device, performing the method, comprising:

obtaining;

(i) acoustic information relating to the cardiac system of said subject;

(ii) electrocardiographic (ECG) information relating to said subject; and

(iii) impedance cardiographic (ICG) information relating to said subject; and

utilizing said acoustic, ECG and ICG information substantially in concert to assess cardiac function.

25. The computer readable medium of claim 24, wherein said act of utilizing comprises using said acoustic and ECG information to improve ICG fiducial point detection.

26. The computer readable medium of claim 25, further comprising computer executable instructions that when executed by said processing device:

confirm the timing of cardiac sounds within said obtained acoustic information utilizing at least in part a portion of said ECG information; and

detect one or more ICG fiducial points utilizing at least in part the confirmed timing within said obtained acoustic information.

27. The computer readable medium of claim 26, wherein said cardiac sounds comprise S1 and S2 heart sounds.

28. The computer readable medium of claim 27, wherein said one or more ICG fiducial points comprises a “

B”

point and a “

X”

point in said obtained ICG information.

29. The computer readable medium of claim 24, wherein said act of utilizing comprises using said acoustic and ECG information to classify a plurality of ICG waveforms.

30. The computer readable medium of claim 24, wherein said act of utilizing comprises using said ECG and ICG information to characterize said acoustic information.

31. A method of providing treatment, comprising:

disposing a sensor apparatus on the thoracic cavity of a living subject, said sensor apparatus comprising a plurality of terminals and an acoustic receptor device;

obtaining acoustic information relating to the cardiac system of said subject using said sensor apparatus;

obtaining electrocardiographic (ECG) information relating to said subject using said sensor apparatus;

obtaining impedance cardiographic (ICG) information relating to said subject using said sensor apparatus; and

utilizing said acoustic, ECG and ICG information substantially in concert to assess cardiac function.

32. The method of claim 31, wherein said acts of obtaining acoustic and ECG information are utilized to improve ICG fiducial point detection.

33. The method of claim 32, further comprising:

confirming the timing of cardiac sounds within said obtained acoustic information utilizing at least in part a portion of said ECG information; and

detecting one or more ICG fiducial points in said obtained ICG information utilizing at least in part the confirmed timing within said obtained acoustic information.

34. The method of claim 31, wherein said steps of obtaining acoustic and ECG information are utilized to improve classification of a plurality of ICG waveforms.

35. The method of claim 31, wherein said steps of obtaining ECG and ICG information are utilized to improve the characterization of said obtained acoustic information.

36. Disposable sensor apparatus for use in determining the cardiac function of a living subject, comprising:

a patch-like substrate;

a first and a second terminal, said first and second terminal spaced a predetermined distance; and

an acoustic receptor device;

wherein said acoustic receptor device and said first and second terminals are disposed on said patch-like substrate.

37. The disposable sensor apparatus of claim 36, further comprising a chamber, said chamber adapted to couple acoustic emissions from said living subject to said acoustic receptor device.

38. The disposable sensor apparatus of claim 37, wherein said acoustic receptor device comprises a piezoelectric device.

39. The disposable sensor apparatus of claim 37, wherein said acoustic receptor device comprises a piezoresistive device.

40. The disposable sensor apparatus of claim 36, wherein said acoustic receptor device is removable from said patch-like substrate and is adapted to be received in a reception apparatus within said patch-like substrate.

41. The disposable sensor apparatus of claim 40, wherein said reception apparatus couples said acoustic receptor device to a chamber, said chamber adapted to couple acoustic emissions from said living subject to said acoustic receptor device.

42. A method of assessing cardiac function within a living subject, comprising:

obtaining acoustic information relating to the cardiac system of said subject;

obtaining electrocardiographic (ECG) signals relating to said subject; and

obtaining impedance cardiographic (ICG) signals relating to said subject;

converting said acoustic information into electrical signals, and providing said acoustic, ECG, and ICG signals to a processing device; and

utilizing said acoustic, ECG and ICG signals to form a profile of the cardiac function of said living subject.

43. The method of claim 42, wherein said acoustic signals are provided to said processing device over a conductor, said conductor also carrying said ICG and ECG electrical signals to said processing device.

44. The method of claim 42, wherein said processing device comprises a digital processor, and said method further comprising converting said acoustic, ECG and ICG signals from an analog domain to a digital domain.

45. The method of claim 42, wherein said acoustic signals are provided to said processing device over a wireless data link.

46. The method of claim 42, wherein said acoustic signals are transported to a component remote from said living subject, and subsequently converted into electrical signals.

47. The method of claim 42, further comprising:

utilizing said obtained acoustic and ECG signals to uniquely characterize at least portions of an ICG waveform; and

separating said characterized portions into at least two different classifications.

48. The method of claim 47, wherein said separation is performed by a signal processing algorithm.

49. The method of claim 47, wherein said separation is performed manually by a user, said manual separation being accomplished via at least a graphical user interface.

50. A method of assessing cardiac regurgitation within a living subject, comprising:

obtaining acoustic information relating to the cardiac system of said subject;

obtaining electrocardiographic (ECG) information relating to said subject; and

obtaining impedance cardiographic (ICG) information relating to said subject; and

utilizing said acoustic, ECG and ICG information collectively to assess cardiac regurgitation within said subject.

51. The method of claim 50, wherein said acts of obtaining acoustic and ECG information are utilized at least in part to determine a location within the subject'"'"'s heart of said regurgitation.

52. The method of assessing cardiac function within a living subject, comprising:

obtaining acoustic information relating to the cardiac system of said subject;

obtaining electrocardiographic (ECG) information relating to said subject;

obtaining impedance cardiographic (ICG) information relating to said subject; and

utilizing a duration of at least a portion of said acoustic information relative to a duration of a QRS complex duration obtained from said ECG information.

53. The method of claim 52, wherein said duration of at least a portion of said acoustic information comprises determining a duration of cardiac sounds from an onset point to a termination point of a particular sound.

54. The method of claim 52, further comprising identifying one or more ICG fiducial points in said obtained ICG information by utilizing, at least in part, said duration.

55. A method of optimizing pacemaker operation, comprising:

disposing sensor apparatus on the thoracic cavity of a living subject;

obtaining acoustic information relating to the cardiac system of said subject using said sensor apparatus;

obtaining electrocardiographic (ECG) information relating to said subject using said sensor apparatus;

obtaining impedance cardiographic (ICG) information relating to said subject using said sensor apparatus;

utilizing said acoustic, ECG and ICG information to assess cardiac function; and

optimizing at least one pacemaker setting based at least in part on said assessment of cardiac function.

56. The method of claim 55, wherein said sensor apparatus comprises a plurality of electrically conductive terminals and an acoustic receptor device.

57. The method of claim 55, wherein said at least one setting comprises a setting for AV or VV timing.

58. A method of assessing quality of cardiac data obtained from a living subject, comprising:

obtaining acoustic information relating to the cardiac system of said subject;

obtaining electrocardiographic (ECG) information relating to said subject;

obtaining impedance cardiographic (ICG) information relating to said subject; and

utilizing said acoustic, ECG and ICG information to assess the quality of one or more cardiac beats.

59. A method of providing treatment to a living subject, comprising:

disposing a sensor apparatus on the thoracic cavity of a living subject;

obtaining acoustic information relating to the cardiac system of said subject using said sensor apparatus;

obtaining electrocardiographic (ECG) information relating to said subject using said sensor apparatus;

obtaining impedance cardiographic (ICG) information relating to said subject using said sensor apparatus;

utilizing said acoustic, ECG and ICG information substantially in concert to assess cardiac function;

beginning a course of treatment for said subject; and

utilizing subsequently obtained acoustic, ECG, and ICG information to assess cardiac function resulting from said treatment.