SPREAD SPECTRUM ELECTRIC TOMOGRAPHY

• US 20090036769A1
• Filed: 07/11/2008
• Published: 02/05/2009
• Est. Priority Date: 07/11/2007
• Status: Abandoned Application

• Current Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Inventors: Zdeblick, Mark J.
• Application Number:
  US12/171,978
• Publication Number:
  US 20090036769A1
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/0536 Impedance imaging, e.g. by tomography
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone

Abstract

Methods for locating a sensor element in vivo, e.g., during evaluation of tissue motion, such as of a cardiac tissue motion, e.g., heart wall motion, via electric tomography are provided. In the subject methods, an electric field is applied to a subject in a manner such that the sensing element is present in the applied electric field, and a property of, e.g., a change in, the applied electric field sensed by the sensing element is employed to evaluate a patient internal parameter of interest, e.g., to evaluate movement of tissue location, to evaluate a internal device parameter, such as movement thereof, etc. The invention allows for robust noise discrimination, e.g., by employing a spread spectrum applied electric field. Also provided are systems and devices for practicing the subject methods. In addition, innovative data displays and systems for producing the same are provided. The subject methods and devices find use in a variety of different applications, including cardiac resynchronization therapy.

Claims

1. A method for evaluating motion of a tissue site in a subject, said method comprising:

(a) generating a spread spectrum electric field so that a tissue site is present in said electric field;

(b) obtaining an initial signal from a first sense electrode stably associated with said tissue site;

(c) deconvolving said initial signal to obtain a final signal; and

(d) evaluating motion of said tissue site from said final signal.

2. The method according to claim 1, wherein said spread spectrum electric field is generated using a pseudorandom number sequence.

3. The method according to claim 2, wherein said spread spectrum electric field is a Frequency-hopping spread spectrum electric field.

4. The method according to claim 1, wherein said spread spectrum electric field is a direct-sequence spread spectrum electric field.

5. The method according to claim 1, wherein said method comprises generating a single spread spectrum electric field.

6. The method according to claim 1, wherein said method comprises generating two or more spread spectrum electric fields.

7. The method according to claim 6, wherein said two or more spread spectrum electric fields are each generated using a unique spread code.

8. The method according to claim 6, wherein said two or more spread spectrum electric fields are generated using a common spread code.

9. The method according to claim 1, wherein said method comprises generating three spread spectrum electric fields.

10. The method according to claim 9, wherein said method comprises generating three substantially orthogonal spread spectrum electric fields.

11. The method according to claim 1, wherein said initial and final signals are voltage.

12. The method according to claim 1, wherein said method further comprises employing obtaining a final signal from a second sense electrode stably associated with a second tissue site.

13. The method according to claim 1, wherein said evaluating comprises determining a cardiac parameter.

14. The method according to claim 1, wherein said spread spectrum electric field is generated internally.

15. The method according to claim 1, wherein said spread spectrum electric field is generated externally.

16. The method according to claim 1, wherein said sense electrode is present on carrier.

17. The method according to claim 16, wherein said carrier is a lead.

18. The method according to claim 17, wherein said lead comprises a single sense electrode.

19. The method according to claim 17, wherein said lead is a multi-electrode lead.

20. The method according to claim 19, wherein said multi-electrode lead is a multiplex lead.

21. The method according to claim 20, wherein said multi-electrode lead comprises a segmented electrode.

22. A system for evaluating movement of a tissue location, said system comprising:

(a) a spread spectrum electric field generation element;

(b) a sense electrode configured to be stably associated with a cardiac tissue location; and

(c) a signal processing element configured to employ a signal obtained from said sense electrode to evaluate movement of tissue in a method according to claim 1.

23. A computer readable storage medium having a processing program stored thereon, wherein said processing program operates a processor to operate a system comprising:

(a) a spread spectrum electric field generation element;

(b) a sense electrode configured to be stably associated with a cardiac tissue location; and

(c) a signal processing element configured to employ a signal obtained from said sense electrode to evaluate movement of tissue

in a method according to claim 1 to perform a method according to claim 1.