DEVICE AND METHOD FOR DETECTING AND TREATING A MYOCARDIAL INFARCTION USING PHOTOBIOMODULATION

• US 20100280563A1
• Filed: 02/28/2007
• Published: 11/04/2010
• Est. Priority Date: 02/28/2007
• Status: Abandoned Application

• Current Assignee: St. Jude Medical AB (Abbott Laboratories)
• Original Assignee: St. Jude Medical AB (Abbott Laboratories)
• Inventors: Norlin-Weissenrieder, Anne, Hartström, Eva, Eckerdal, Johan, Strandberg, Hans, Henriquez, Leda, Naeslund, Annika, Sjögren, Mikael
• Application Number:
  US12/528,363
• Publication Number:
  US 20100280563A1
• Time in Patent Office: Days
• US Class Current: 607/3
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/358 Detecting ST segments
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 2005/063 comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 2005/0659 infrared
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: A61N 5/067 using laser light

Abstract

In an implantable medical device and a method for treating cardiac tissue of a heart of a patient with therapeutic light, a myocardial infarction is detected and a location the myocardial infarction is identified. A therapy session is initiated by selectively activating one or more of a number of light emitting units arranged in at least one medical lead connectable to the implantable medical device, to emit therapeutic light toward the detected location of the myocardial infarction upon detection of an occurrence of the myocardial infarction.

Claims

1. An implantable medical device comprising:

a pulse generator that emits cardiac stimulating pacing pulses;

a medical lead connected to said pulse generator that delivers said pulses in vivo to cardiac tissue of the heart of a patient;

a myocardial infarction detection unit that detects a myocardial infarction and identifies a location of said myocardial infarction;

a therapy circuit connected to a plurality of light emitting units carried by said medical lead, each of said light emitting units being operated by said therapy circuit to emit therapeutic light; and

a control circuit connected to said myocardial infarction detection unit and to said therapy circuit, said control circuit being configured to initiate a therapy session via said therapy circuit, in which one or more of said plurality of light emitting is/are selectively activated to emit said therapeutic light toward the detected location of the myocardial infarction upon detection of an occurrence of the myocardial infarction.

2. The implantable medical device according to claim 1, wherein said therapy circuit is configured to activate said light emitting units to emit said therapeutic light according to a treatment protocol.

3. The implantable medical device according to claim 2, wherein said treatment protocol includes treatment parameters comprising:

emitting intervals of said therapeutic light, intensity of said emitted therapeutic light, wavelength of said emitted light, and intermittence of said emitted therapeutic light.

4. The implantable medical device according to claim 1, wherein each of said plurality of light emitting units comprises at least one light emitting diode.

5. The implantable medical device according to claim 1, wherein said light emitting units are arranged in an array arranged along an outer surface of a lead body of said medical lead.

6. The implantable medical device according to claim 1, wherein each of said plurality of light emitting units comprises at least one optical fibre fiber that conducts light emitted from at least one light source said implantable medical device, and wherein said therapy circuit selectively activates said at least one light source and/or at least one optical fiber to cause light conducted in one or more optical fiber to emanate from said one or more optical fiber toward said detected location.

7. The implantable medical device according to claim 6, wherein the at least one light source is a laser source.

8. The implantable medical device according to claim 1, wherein said medical lead comprises a plurality of electrodes, and wherein said myocardial infarction detection unit comprises:

an impedance measuring circuit connected to said electrodes and configured to;

apply excitation current pulses between respective electrode pairs including at least a first and at least a second electrode; and

measure the impedance in the tissues between said at least first and said at least second electrode of said electrode pairs to the excitation current pulses; and

a myocardial infarct detector that evaluates said measured impedances by detecting changes in said impedances associated with the myocardial infarction and to determine the location of said myocardial infarction using said evaluation.

9. The implantable medical device according to claim 8, wherein said myocardial infarct detector configured to compare measured impedances with a stored reference impedance template to detect the occurrence of the myocardial infarction and the location of said myocardial infarction from a result of the comparison.

10. The implantable medical device according to claim 9, wherein said myocardial infarct detector configured to:

determine impedance value ratios for a cardiac cycle by determining a maximum impedance and a minimum impedance, respectively, measured by the impedance measuring circuit during a cardiac cycle;

determine an impedance value ratio being below a predetermined impedance value ratio threshold to be consistent with a myocardial infarction; and

determine the impedance value ratio being smallest of the impedance value ratios being below said predetermined impedance value ratio threshold to indicate the location of the myocardial infarction.

11. The implantable medical device according to claim 9, wherein said myocardial infarct detector is configured to:

calculate a respective maximum time derivative of the measured impedance curves;

determine a maximum impedance time derivative being below a predetermined impedance time derivative threshold to be consistent with a myocardial infarction; and

determine the maximum impedance time derivative being lowest of the maximum impedance time derivatives being below said predetermined impedance time derivative threshold to indicate the location of the myocardial infarction.

12. The implantable medical device according to claim 1, wherein said medical lead comprises a plurality of electrodes, and wherein said myocardial infarction detection unit comprises:

an intracardiac electrogram measuring circuit connected to said electrodes that measures intracardiac electrograms using respective pairs of said electrodes; and

a myocardial infarct detector that evaluates said intracardiac electrograms to detect changes consistent with a myocardial infarction and to determine the location of said myocardial infarction using said evaluation.

13. The implantable medical device according to claim 12, wherein said myocardial infarct detector is configured to:

determine a ST segment elevation being above a predetermined ST segment threshold as being consistent with the occurrence of a myocardial infarction; and

determine the intracardiac electrogram having the largest ST segment elevation of the ST segments being above a predetermined ST segment threshold as indicating the location of said myocardial infarction.

14. The implantable medical device according to claim 8, wherein said myocardial infarct detector is, after an initiation of a therapy session, configured to:

monitor impedances obtained by at least an electrode pair indicating the location of said myocardial infarction to determine whether said impedances indicate that said therapy session should be terminated and/or said treatment parameters should be adjusted.

15. The implantable medical device according to claim 14, wherein said myocardial infarct detector is adapted configured to:

determine impedance value ratios for successive cardiac cycles; and

determine that said therapy session should be terminated if a predetermined number of said impedance value ratios are found to be above said impedance value ratio threshold.

16. The implantable medical device according to claim 14, wherein said myocardial infarct detector is configured to:

calculate maximum time derivatives of the measured impedance curves for successive cardiac cycles; and

determine that said therapy session should be terminated if a predetermined number of said maximum impedance time derivatives are found to be above a predetermined impedance time derivative threshold.

17. The implantable medical device according to claim 12, wherein said myocardial infarct detector is configured to:

monitor intracardiac electrograms obtained by at least an electrode pair indicating the location of said myocardial infarction to determine whether said intracardiac electrograms indicate that said therapy session should be terminated and/or said treatment parameters should be adjusted.

18. The implantable medical device according to claim 17, wherein said myocardial infarct detector is configured to:

determine ST segments for successive cardiac cycles; and

determine that said therapy session should be terminated if a predetermined number of said ST segment elevations are found to be below a predetermined ST segment elevation threshold.

19. The implantable medical device according to claim 1, wherein each of said light emitting units emits coherent and monochromatic light.

20. The implantable medical device according to claim 1, wherein each of said light emitting unit emits light having a wavelength in the range of 600 nm-1000 nm.

21. The implantable medical device according to claim 1 comprising a communication unit, and wherein said control circuit is configured to, upon detection of an occurrence of a myocardial infarction, send a notification to a medical care institution via said communication unit of and at least one external communication network, said notification including at least an identity of the patient and information related to a detected myocardial infarction.

22. The implantable medical device according to claim 21, wherein said communication unit 30) is configured to communicate with an extracorporeal communication device, said communication device being configured to receive said notification and to transmit said notification via said communication network to said medical care institution.

23. The implantable medical device according to claim 22, wherein said extracorporeal communication device is a mobile phone, a pager or a PDA (“

Personal Digital Assistant”

).

24. The implantable medical device according to claim 21, wherein said communication unit of said medical device is configured to communicate with an extracorporeal home monitoring unit connected to said at least one communication network, said home monitoring unit being adapted to receive said notification and to transmit said notification via said communication network to said medical care institution.

25. The implantable medical device according to claim 1, further comprising a notifying device configured to, upon detection of an occurrence of myocardial infarction, notify said patient that the myocardial infarct has been detected and/or that therapy has been initiated.

26. The implantable medical device according to claim 25, wherein said notifying device is a vibration unit.

27. A method for treating cardiac tissue of a heart of a patient with therapeutic light using an implantable medical device including a pulse generator that emits cardiac stimulating pacing pulses and connectable to at least one medical lead for delivering said pulses in vivo to cardiac tissue of a heart of a patient, comprising the steps of:

detecting in vivo a myocardial infarction and identifying a location of said myocardial infarction; and

automatically initiating an in vivo therapy session by selectively activating one or more of a plurality of light emitting units carried said at least one medical lead to emit therapeutic light detected location of the myocardial infarction upon detection of an occurrence of the myocardial infarction.

28. The method according to claim 27, further comprising the step of:

selectively activating said light emitting units to emit said therapeutic light according to a treatment protocol.

29. The method according to claim 28, wherein said treatment protocol includes treatment parameters comprising:

emitting intervals of said therapeutic light, intensity of said emitted therapeutic light, wavelength of said emitted light, and intermittence of said emitted therapeutic light.

30. The method according to claim 27 comprising forming each of said plurality of light emitting units as at least one light emitting diode.

31. The method according to claim 27, comprising arranging said light emitting units in an array arranged along an outer surface of a lead body of said medical lead.

32. The method according to claim 27, further comprising the step of:

emitting said therapeutic light via at least one optical fiber that conducts light from at least one light source in said implantable medical device to cause said conducted therapeutic light to emanate from said at least one optical fiber toward the detected location of the myocardial infarction upon detection of the occurrence of the myocardial infarction.

33. The method according to claim 32, comprising employing a laser source as said at least one light source.

34. The method according to claim 27, wherein the step of detecting a myocardial infarction and identifying a location of said myocardial infarction comprises the steps of:

applying excitation current pulses between respective electrode pair including at least a first and at least a second electrode;

measuring the impedance in the tissues between said at least first and said at least second electrode of said electrode pairs to the excitation current pulses;

evaluating said measured impedances by detecting changes in said impedances being consistent with a myocardial infarction; and

determining a location of said myocardial infarction using said evaluation.

35. The method according to claim 34, wherein the step of evaluating comprises the step of:

comparing measured impedances with a stored reference impedance template to detect an occurrence of a myocardial infarction and a location of said myocardial infarction from the result of the comparison.

36. The method according to claim 35, wherein the step of comparing comprises the steps of:

determining impedance value ratios for a cardiac cycle by determining a maximum impedance and a minimum impedance, respectively, measured by the impedance measuring circuit during a cardiac cycle;

determining an impedance value ratio being below a predetermined impedance value ratio threshold to be consistent with a myocardial infarction; and

determining the impedance value ratio being smallest of the impedance value ratios being below said predetermined impedance value ratio threshold to indicate the location of the myocardial infarction.

37. The method according to claim 35, wherein the step of comparing comprises the steps of:

calculating a respective maximum time derivative of the measured impedance curves;

determining a maximum impedance time derivative being below a predetermined impedance time derivative threshold to be consistent with a myocardial infarction; and

determining the maximum impedance time derivative being lowest of the maximum impedance time derivatives being below said predetermined impedance time derivative threshold to indicate the location of the myocardial infarction.

38. The method according to claim 27, wherein said medical lead comprises a plurality of electrodes, and further comprising the steps of:

measuring intracardiac electrograms using respective pairs of said electrodes; and

evaluating said intracardiac electrograms to detect changes being consistent with a myocardial infarction and to determine a location of said myocardial infarction using said evaluation.

39. The method according to claim 38, wherein the step of evaluating comprises the steps of:

determining a ST segment elevation being above a predetermined ST segment threshold as being consistent with the occurrence of a myocardial infarction; and

determining the intracardiac electrogram having the largest ST segment elevation of the ST segment elevations being above a predetermined ST segment threshold as indicating the location of said myocardial infarction.

40. The method according to claim 35, further comprising the step of:

monitoring impedances obtained by an electrode pair indicating the location of said myocardial infarction to determine whether said impedances indicate that said therapy session should be terminated and/or said treatment parameters should be adjusted.

41. The method according to claim 40, further comprising the steps of:

determining impedance value ratios for successive cardiac cycles; and

determining that said therapy session should be terminated if a predetermined number of said impedance value ratios are found to be above said impedance value ratio threshold.

42. The method according to claim 40, further comprising the steps of:

calculating maximum time derivatives of the measured impedance curves for successive cardiac cycles; and

determining that said therapy session should be terminated if a predetermined number of said maximum impedance time derivatives is found to be above a predetermined impedance time derivative threshold.

43. The method according to claim 35, further comprising the step of:

monitoring intracardiac electrograms obtained by an electrode pair indicating the location of said myocardial infarction to determine whether said intracardiac electrograms indicate that said therapy session should be terminated and/or said treatment parameters should be adjusted.

44. The method according to claim 43, further comprising the steps of:

determining ST segments for successive cardiac cycles; and

determining that said therapy session should be terminated if a predetermined number of said ST segment elevations are found to be below a predetermined ST segment threshold.

45. The method according to claim 27 comprising, from said light emitting unit emitting coherent and monochromatic light.

46. The method according to claim 27 comprising, from said light emitting unit emitting light having a wavelength in a range of 600 nm-1000 nm.

47. The method according to claim 27, further comprising the step of, upon detection of an occurrence of the myocardial infarction, sending a notification to a medical care institution via a communication unit of said medical device and at least one external communication network, and including in said notification including at least an identity of the patient and information related to a detected myocardial infarction.

48. The method according to claim 47, wherein the step of sending a notification comprises the steps of:

communicating with an extracorporeal communication device and, at said communication device receiving said notification and transmitting said notification via said communication network to said medical care institution.

49. The method according to claim 48 comprising employing, as said extracorporeal communication device, a mobile phone, a pager or a PDA (“

Personal Digital Assistant”

).

50. The method according to claim 48, wherein the step of sending a notification comprises the step steps of:

communicating with an extracorporeal home monitoring unit connected to said at least one communication network and, at said home monitoring unit, receiving said notification and transmitting said notification via said communication network to said medical care institution.

51. The method according to claim 27, further comprising the step of, upon detection of an occurrence of the myocardial infarction, automatically notifying said patient that the myocardial infarct has been detected and/or that therapy has been initiated.

52. The method according to claim 51, comprising notifying the patient via a vibration unit.

53-59. -59. (canceled)

60. A computer-readable medium encoded with programming instructions, said medium being loadable into a control unit of an implantable medical device comprising a pulse generator that emits cardiac stimulation pulses and at least one medical lead connected to the pulse generator for delivering the stimulating pulses in vivo to cardiac tissue of a heart of a patient, and a plurality of light emitting units carried by the at least one medical lead, said programming instructions causing said control unit to:

detect in vivo a myocardial infarction and to identify a location of the myocardial infarction; and

initiate an in vivo therapy session by selectively activating one or more of said light emitting units to emit therapeutic light toward the detected location of the myocardial infarction upon detection of an occurrence of the myocardial infarction.