Controlling heart performance using a non-excitatory electric field

• US 6,317,631 B1
• Filed: 08/13/1998
• Issued: 11/13/2001
• Est. Priority Date: 01/08/1996
• Status: Expired due to Term

• Current Assignee: Impulse Dynamics NV
• Original Assignee: Impulse Dynamics NV
• Inventors: Ben-Haim, Shlomo, Darvish, Nissim, Fenster, Maier, Yuval, Mika
• Primary Examiner(s): Layno, Carl H.
• Application Number:
  US09/101,723
• Time in Patent Office: 1,188 Days
• Field of Search: 607/2-5, 607/9
• US Class Current: 607/9
• CPC Class Codes: A61B 17/22012 in direct contact with, or very close to, the obstruction or concrement for removing obstructions in blood vessels by laser A61B18/245
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/0243 for immobilizing local areas of the heart, e.g. while it beats trocars attached to inner organs or inner body tissue A61B2017/3488
• CPC Class Codes: A61B 2017/22008 used or promoted
• CPC Class Codes: A61B 2018/00392 Transmyocardial revascularisation
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: A61B 5/6856 with a distal loop
• CPC Class Codes: A61B 5/6858 with a distal basket, e.g. expandable basket
• CPC Class Codes: A61B 5/6859 with multiple distal splines
• CPC Class Codes: A61M 2025/0166 : Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• 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 1/3628 : using sub-threshold or non-excitatory signals
• CPC Class Codes: A61N 1/36514 : controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36557 : controlled by chemical substances in blood
• CPC Class Codes: A61N 1/36564 : controlled by blood pressure
• CPC Class Codes: A61N 1/36578 : controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• CPC Class Codes: A61N 1/368 : comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

A method of modifying the force of contraction of at least a portion of a heart chamber, including providing a subject having a heart, comprising at least a portion having an activation, and applying a non-excitatory electric field having a given duration, at a delay after the activation, to the portion, which causes the force of contraction to be increased by at least 5%.

Claims

1. A method of modifying the activity of the heart or of a portion thereof, comprising applying to said heart or a portion thereof a non-excitatory electric field of a magnitude, shape, duty cycle, phase, frequency and duration suitable to obtain a desired change, to modify an activity of the heart or a portion thereof, wherein said field is applied at a time at which it is unable to generate a propagating action potential.

2. A method according to claim 1, wherein the portion of the heart to which the non-excitatory field is applied is a heart chamber.

3. A method according to claim 1, wherein the step of applying a non-excitatory electric field comprises applying an alternating current electric field.

4. A method according to claim 1, wherein the step of applying non-excitatory electric field comprises applying an electric field that has a temporal envelope selected from the group consisting of an exponential temporal envelope, a sinusoidal temporal envelope, a square temporal envelope, a triangular temporal envelope, a ramped temporal envelope, a sawtooth temporal envelope and a biphasic temporal envelope.

5. A method according to claim 1, wherein the desired change is an increase of the force of contraction of said heart, heart chamber or portion thereof.

6. A method according to claim 1, wherein the desired change is an increase of the stroke volume of a chamber of the heart.

7. A method according to claim 1, wherein the desired change is an increase of the output flow of a chamber of the heart.

8. A method according to claim 1, wherein the desired change is a change in pressure.

9. A method according to claim 8, wherein the pressure is end diastolic pressure or end systolic pressure of a chamber or aortic pressure.

10. A method according to claim 1, wherein the desired change is a change of the heart rate.

11. A method according to claim 1, comprising sensing the activation of a portion of the heart at a suitable location, and thereafter calculating or estimating therefrom the activation time of the portion of the heart activity of which it is desired to modify.

12. A method according to claim 11, further comprising determining the delay at which the non-excitatory electric field is to be applied from said activation time.

13. A method according to claim 11, wherein the activation is sensed by sensing a value of a parameter of an ECG, and wherein the activation time is estimated based on a delay value associated with the value of the parameter.

14. A method according to claim 1, wherein the portion of the heart the activity of which it is desired to modify comprises a plurality of sub-portions having each independently defined activations, and wherein separate non-excitatory electric fields are applied to a plurality of said sub-portions, independently or in synchronization with one another.

15. A method according to claim 1, wherein the activation of the heart, the heart chamber, or of portions thereof, is obtained by pacing, and wherein the application of the non-excitatory electric field is synchronized with the pacing signal and is effected with a timing relative to the pacing signal.

16. A method according to claim 1, wherein a defibrillating signal is provided to the heart, and wherein the application of the non-excitatory electric field is synchronized with said defibrillating signal.

17. A method according to claim 1, wherein the electric field is applied at one or more of the positions selected from among the group consisting essentially of internally or externally to the heart, within a blood vessel, intramuscularly, along the normal conduction direction or perpendicularly thereto.

18. A method according to claim 1 wherein the electric field is applied using electrodes selected from unipolar electrodes or bipolar electrodes.

19. A method according to claim 1, wherein the application of the non-excitatory field is repeated during a plurality of heart beats, and wherein said repeated application is effected by skipping the application of the field to some of the beats in a train of consecutive heart beats.

20. A method according to claim 1, wherein the change comprises selectively and reversibly increasing or reducing the contractility of one of the portions or ventricles of the heart relative to another portion or to the other ventricle.

21. A method according to claim 1, further comprising determining a desired range of values for at least one parameter of cardiac activity and controlling at least a local force of contraction of the heart to maintain said parameter within the desired range.

22. A method according to claim 1, wherein the application of the non-excitatory field is repeated during a plurality of heart beats, and wherein said repeated application is effected by gradually reducing the frequency at which the beats are skipped.

23. A method according to claim 1, wherein the application of the non-excitatory field is repeated during a plurality of heart beats, and wherein said repeated application is effected by changing between beats the size of the portion of the heart to which the field is applied.

24. A method of performing cardiac surgery comprising applying to the heart, or to a portion thereof a non-excitatory electric field of a magnitude, shape, duty cycle, phase, frequency and duration suitable to control the electro-mechanical activity of the tissue in the area on which surgery is to be performed, wherein said field is inhibitory of a propagating action potential, and thereafter performing the required surgical procedure on said area.

25. A method of performing cardio-vascular surgery comprising applying to the heart chamber or to a portion thereof a non-excitatory electric field of a magnitude, shape, duty cycle, phase, frequency and duration suitable to reduce the output flow, contractility, or pressure thereof, when surgery is performed on tissue perfused by the flow of said chamber, wherein said field is unable to generate a propagating action potential, and thereafter performing the required surgical procedure on said area.

26. A method of reducing an output of a chamber of a heart, comprising applying to a portion of said heart chamber a non-excitatory electric field of a magnitude, shape, duty cycle, phase, frequency and duration suitable to obtain a desired change, to modify an activity of the heart or a portion thereof, wherein said field is applied at a time at which it is unable to generate a propagating action potential, and wherein reducing the output of the chamber is obtained by reducing the reactivity of said portion, or its sensitivity, to an activation signal, or by reversibly blocking its conduction pathway.

27. A method of treating an abnormal activation of the heart, particularly fibrillation, comprising applying to said heart or to a portion thereof a non-excitatory electric field of a magnitude, shape and duration suitable to treat the abnormal activation condition, wherein said field is unable to generate a propagating action potential.

28. A method of modifying the electro-mechanical activation of at least a portion of a heart, comprising mapping the activation profile of the portion, determining a desired change in the activation, and modifying the conduction velocity in a non-arrhythmic segment of the portion, wherein the non-excitatory electric field is of a magnitude, shape, duty cycle, phase, frequency and duration suitable to obtain the desired change.

29. A method of modifying the activation profile of at least a portion of a heart, comprising mapping the activation profile of said portion, determining the desired change in the activation profile and changing the refractory period of at least a segment of the portion, wherein the non-excitatory electric field is of a magnitude, shape, duty cycle, phase, frequency and duration suitable to obtain a desired change, and wherein said segment is selected from a segment that is not part of a reentry circuit or an arrhythmia focus in the heart, a segment that is a part of a reentry circuit or an arrhythmia focus in the heart, or an ischemic segment.

30. A method of modifying the activation profile of at least a portion of a heart, comprising mapping the activation profile of said portion, determining the desired change in the activation profile and reversibly blocking the activation of at least a segment of the portion, wherein the non-excitatory electric field is of a magnitude, shape, duty cycle, phase, frequency and duration suitable to obtain a desired change, and wherein said segment is selected from a segment that is not part of a reentry circuit or an arrhythmia focus in the heart, a segment that is a part of a reentry circuit or an arrhythmia focus in the heart, or an ischemic segment.

31. A method of treating a segment of the heart which induces arrhythmias due to an abnormally low excitation threshold, comprising identifying the segment and applying thereto a desensitizing electric field such that said excitation threshold is increased to a normal range of values.

32. Heart control apparatus, comprising circuitry for generating a non-excitatory electric field to modify an activity of the heart or a portion thereof, and electrodes for applying to a heart or to a portion thereof said non-excitatory electric field, wherein said circuitry for generating a non-excitatory electric field generates a field with a timing relative to the activation of the heart or of a portion thereof, and of a magnitude, shape, duty, cycle, phase, frequency, and duration which is unable to generate a propagating action potential.

33. Apparatus according to claim 32, comprising means for generating an AC non-excitatory electric field.

34. Apparatus according to claim 32, comprising means for imparting to the non-excitatory electric field a temporal envelope selected from exponential temporal envelope, sinusoidal temporal envelope, square temporal envelope, triangular temporal envelope, ramped temporal envelope, sawtooth temporal envelope, and biphasic temporal envelope.

35. Apparatus according to claim 32, further comprising means for mapping the activation profile of the portion.

36. Apparatus according to claim 35, further comprising circuitry for modifying the conduction velocity in a non-arrhythmic segment of a heart portion.

37. Heart control apparatus according to claim 32, wherein the electrodes are suitable to be positioned externally to the body.

38. Heart control apparatus according to claim 32, said apparatus being suitable for controlling a parameter selected from the force of contraction, heart rate, stroke volume, chamber or aortic pressure, or output flow.

39. Heart control apparatus according to claim 32, wherein the electrodes comprise at least one unipolar electrode and a housing which functions as a second electrode.

40. Apparatus according to claim 32, comprising at least two electrodes, suitable to apply said non-excitatory electric field across at least one predetermined portion of the heart.

41. Apparatus according to claim 32, comprising at least three electrodes, wherein each pair of said at least three electrodes is selectively and separately electrifiable.

42. Apparatus according to claim 32, comprising a sensor adapted to sense the activation of a portion of a heart, and field application circuitry adapted to apply said field to the electrodes as a response to activation sensed by said sensor.

43. Apparatus according to claim 42, further comprising logic circuitry to calculate the application parameters of the electric field from the activation sensed by the sensor.

44. Apparatus according to claim 43, wherein the application parameters include a delay time from the sensed activation.

45. Apparatus according to claim 42, further comprising multiple sensors that sense independently or in a combined logic.

46. Apparatus according to claim 32, further comprising feedback control means to measure at least one physiological response to the electrification of the electrodes, and to modify the application parameters of the non-excitatory electric field as a result of said responses in order to maintain said responses within a predetermined range of values.

47. Apparatus according to claim 32, further comprising synchronization circuitry, to synchronize the application of the non-excitatory electric field to the pacing signal generated by a pacemaker wherein the pacemaker and the remainder of the apparatus are contained in a common housing and use common electrodes.

48. Apparatus according to claim 32, further comprising synchronization circuitry, to synchronize the application of the non-excitatory electric field to the defibrillating signal generated by a defibrillator wherein the defibrillator and the remainder of the apparatus are contained in a common housing and use common electrodes.

49. Apparatus according to claim 32, comprising circuitry for sensing the activation by sensing a value of a parameter of an ECG, and circuitry for estimating the activation time based on a delay value associated with the value of the parameter.

50. Apparatus according to claim 32, comprising means for electrifying the electrodes using a single signal which combines a pacing signal and a non-excitatory electric field.

51. Apparatus according to claim 32, comprising controlling means and memory means to coordinate the electrification of all the electrodes.

52. Apparatus according to claim 32, comprising circuitry for applying separate non-excitatory electric fields, independently or in synchronization with one another, to a plurality of sub-portions of a heart, having each independently defined activations.

53. Cardiac surgery aiding apparatus, comprising circuitry for generating a non-excitatory electric field, and electrodes for applying to a heart or to a portion thereof said non-excitatory electric field, wherein said circuitry for generating a non-excitatory electric field generate a field of a magnitude, shape duty cycle, phase, frequency and duration suitable to control the electro-mechanical activity of the tissue in the area on which surgery is to be performed, and wherein said field is unable to generate a propagating action potential.

54. Cardio-vascular surgery aiding apparatus, comprising circuitry for generating a non-excitatory electric field, and electrodes for applying to a heart chamber or to a portion thereof said non-excitatory electric field to modify an activity of the heart or a portion thereof, wherein said circuitry for generating a non-excitatory electric field generates a field of a magnitude, shape, duty cycle, phase, frequency and duration suitable to reduce the output flow, contractility, or pressure of said chamber, when surgery is performed on tissue perfused by the flow of said chamber, and wherein said field is unable to generate a propagating action potential, and thereafter performing the required surgical procedure on said area.

55. A method of modifying the activity of a heart or portion thereof, comprising providing one implantable light source which generates pulses of light, for at least 1000 cardiac cycles, over a period of less than 5000 cycles or a plurality of light sources each attached to a different site of the heart, and a wave guide for providing non-damaging intensities of light from the light source to at least one site of the heart.

56. A method of modifying the activity of the heart or a portion thereof, comprising irradiating the portion with radio frequency radiation synchronized to the activation of said heart or portion thereof, and repeating said irradiation at at least 100 cardiac cycles, during a period of less than 1000 cardiac cycles.

57. A method of controlling a heart, comprising applying a non-excitatory electric field to a first portion of a chamber of said heart, such that a force of contraction of the first portion is lessened, and applying a non-excitatory electric field to a second portion of a chamber, such that a force of contraction of the second portion is increased.

58. Apparatus for modifying the activity of a heart or portion thereof, comprising one implantable light source which generates pulses of light, for at least 1000 cardiac cycles, over a period of less than 5000 cycles or a plurality of light sources each attached to a different site of the heart, and a wave guide for providing non-damaging intensities of light from the light source to at least one site of the heart.

59. Apparatus for modifying the activity of the heart or a portion thereof, comprising means for irradiating the portion with radio frequency radiation synched to the activation, and means for repeating irradiating at at least 100 cardiac cycles, during a period of less than 1000 cardiac cycles.

60. Heart control apparatus comprising circuitry for applying a non-excitatory electric field to a first portion of a heart chamber, such that a force of contraction of the first portion is lessened, and circuitry for applying a non-excitatory electric field to a second portion of a chamber, such that a force of contraction of the second portion is increased.