ELECTRIC TOMOGRAPHY

• US 20080058656A1
• Filed: 03/30/2007
• Published: 03/06/2008
• Est. Priority Date: 10/08/2004
• Status: Abandoned Application

• Current Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Inventors: Savage, George, Costello, Benedict, Robertson, Timothy, Zdeblick, Mark, Thompson, Todd, Colliou, Olivier
• Application Number:
  US11/731,786
• Publication Number:
  US 20080058656A1
• Time in Patent Office: Days
• US Class Current: 600/508
• CPC Class Codes: A61B 2562/046 in a matrix array
• 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 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

Methods for evaluating motion of a tissue, such as of a cardiac location, e.g., heart wall, via electrical field tomography are provided. In the subject methods, an sensing element is stably associated with a tissue location of interest. Signals obtained from the sensing element are obtained to evaluate movement of the tissue location. 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 obtaining a parameter in a subject, said method comprising:

(a) generating an electric field so that a tissue site is present in said electric field; and

(b) employing a signal from a first sense electrode stably associated with said tissue site to obtain said parameter.

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

3. The method according to claim 2, wherein said single electric field is oriented in a direction of motion of interest.

4. The method according to claim 3, wherein said single electric field is reoriented at least once over a given period of time.

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

6. The method according to claim 5, wherein said method comprises generating three electric fields.

7. The method according to claim 6, wherein said method comprises generating three substantially orthogonal electric fields.

8. The method according to claim 1, wherein said method comprises generating more than three electric fields.

9. The method according to claim 8, wherein said method comprises generating six electric fields.

10. The method according to claim 1, wherein said signal is a voltage.

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

12. The method according to claim 1, wherein said parameter is a cardiac parameter.

13. The method according to claim 1, wherein said parameter is selected from the group consisting of:

ejection fraction, cardiac output, stroke volume, LV volume, LV diameter, LV end diastolic volume, LV end diastolic diameter, LV end systolic volume, LV end systolic diameter, contractility, dP/dt, dP/dt_max, LV twist index, mitral regurgitation, myocardial strain, myocardial strain rate, myocardial strain rate_max, myocardial position, cardiac wall motion, interventricular synchrony, intraventricular synchrony, septal lateral wall motion delay, septal posterior wall motion delay (SPWMD), interventricular mechanical delay (IVMD), mitral annular position, inter-electrode distances, isovolumetric relaxation time (IVRT), deceleration time (DT), atrial filling period (A_dur, at annulus), time from mitral valve opening to E velocity, beat-to-beat variability, valve timing, QRS duration, myocardial velocity, myocardial acceleration, systolic velocity, time to onset of systolic velocity, time to peak systolic velocity, time to peak post-systolic velocity, ET systolic measurements, S_m-ET (maximal velocity of a segment of myocardium), time to maximal systolic displacement (Td), e-wave velocity, a-wave velocity, mitral annular velocity, peak systolic mitral annular velocity, mitral annular acceleration, ET diastolic measurements, E_a-ET (maximal velocity of the mitral valve annulus during early diastolic filling), peak acceleration, time to peak acceleration, early diastolic filling velocity (E), filling velocity after atrial contraction (A), ratio of E/A, maximal acceleration, early diastolic deceleration slope, peak rapid filling rate, peak atrial filling rate, fractional filling rates, early diastolic myocardial tissue velocity (E_m), diastolic myocardial tissue velocity after atrial contraction (A_m), ratio of E_m/A_m, propagation velocity, rate of decline in LV pressure in early diastole (−

dP/dt), left atrial pressure, ventricular pressure, end diastolic pressure, end systolic pressure, aortic pressure, valvular gradient, valvular regurgitation, blood flow, and mitral valve flow.

14. The method according to claim 1, wherein said parameter is selected from the group consisting of:

transthoracic impedance, cardiac capture threshold, phrenic nerve capture threshold, temperature, respiratory rate, activity rate, hematocrit, heart sounds, sleep apnea determination.

15. The method according to claim 1, wherein said electric field is generated internally.

16. The method according to claim 1, wherein said electric field is generated externally.

17. The method according to claim 1, wherein said sense electrode is not present on a lead.

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

19. The method according to claim 18, wherein said carrier is a lead.

20. The method according to claim 18, wherein said carrier is a guidewire.

21. The method according to claim 18, wherein said carrier is a sheath.

22. The method according to claim 19, wherein said lead comprises a single sense electrode.

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

24. The method according to claim 23, wherein said multi-electrode lead is a multiplex lead.

25. The method according to claim 23, wherein said multi-electrode lead comprises a segmented electrode.

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

(a) an 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.

42. A computer readable storage medium having a processing program stored thereon, wherein said processing program operates a processor to operate a system according to claim 31 to perform a method according to claim 1.

26-30. -30. (canceled)

32-41. -41. (canceled)

43. (canceled)

44. A method for evaluating movement of a first cardiac tissue at a site within a subject, said method comprising:

(a) generating an electric field so that said tissue is present in said electric field;

(b) monitoring voltage at a first sense electrode stably associated with said first cardiac tissue at said site to obtain data; and

(c) using said data to evaluate movement of said first cardiac tissue at said site within said subject.

45. The method according to claim 44, wherein said method comprises generating a single electric field.

46. The method according to claim 45, wherein said single electric field is oriented in direction of motion of interest.

47. The method according to claim 46, wherein said single electric field is reoriented at least once over a given period of time.

48. The method according to claim 44, wherein said method comprises generating two or more electric fields.

49. The method according to claim 48, wherein said method comprises generating three electric fields.

50. The method according to claim 49, wherein said method comprises generating three substantially orthogonal electric fields.

51. The method according to claim 44, wherein said method comprises generating more than three electric fields.

52. The method according to claim 51, wherein said method comprises generating six electric fields.

53-112. -112. (canceled)