Hemodynamically responsive system for and method of treating a malfunctioning heart

• US 4,774,950 A
• Filed: 10/06/1987
• Issued: 10/04/1988
• Est. Priority Date: 10/06/1987
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Leonard Bloom
• Inventors: Cohen, Todd J.
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/105,030
• Time in Patent Office: 364 Days
• Field of Search: 128/419 D, 128/419 PG, 128/419 P, 128/705, 128/696, 128/695, 128/786
• US Class Current: 607/6
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

A system for and method of treating a malfunctioning heart is based on hemodynamics. The mean arterial pressure (MAP) mean right atrial pressure (MRAP), mean right ventrical pressure (MRVP), mean left atrial pressure (MLAP), mean left ventrical pressure (MLVP) or mean central venous pressure (MCVP) is sensed. The long term mean baseline pressure is monitored and if the short term current mean pressure differs therefrom by a predetermined value, an indication of hemodynamic compromise, cardioversion/defibrillation is effected. In a second embodiment, the determination of whether the difference between mean baseline and mean current pressure is undertaken after a rate criteria (for example a heart rate above 155 b.p.m. has been met. In a third embodiment, the rate and pressure criteria both must exist at the same time, before cardioverting/defibrillation is initiated. In a fourth embodiment, a microprocessor is used. The system may be integrated with antitachycardia and/or antibradycardia pacemakers.

Claims

1. A system for treating a malfunctioning heart, the system including storage means for storing electrical energy, electrode means for electrically coupling the storage means to the heart, pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said sensing means for developing a variable first signal representing mean baseline pressure over a period of predetermined length, means responsive to output from said means for developing a second signal representing mean current pressure over a period of given length of lesser duration than the predetermined period, and means responsive to output from the means for developing the variable first signal and the second signal for charging and enabling discharge of the electrical energy stored by said storage means across said electrode means and into the heart upon change in mean current pressure of at least a predetermined amount from the mean baseline pressure.

2. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing right atrial pressure.

3. The system of claim 2, including means responsive to the variable first signal and to the second signal for providing a control signal indicative of mean current right atrial pressure increasing by at least a predetermined amount from mean baseline right atrial pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

4. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing right ventricular pressure.

5. The system of claim 4, including means responsive to the variable first signal and to the second signal for providing a control signal indicative of mean left ventricular pressure increasing by at least a predetermined amount from mean baseline right ventricular pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

6. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing central venous pressure.

7. The system of claim 6, including means responsive to the first signal and to the second signal for providing a control output signal indicative of mean central venous pressure increasing by at least a predetermined amount from mean baseline central venous pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

8. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing left atrial pressure.

9. The system of claim 8, including means responsive to the first signal and to the second signal for providing a control signal indicative of mean left atrial pressure increasing by at least a predetermined amount from mean baseline left atrial pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

10. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing left ventricular pressure.

11. The system of claim 10, including means responsive to the first signal and to the second signal for providing a control signal indicative of mean left ventricular pressure increasing by at least a predetermined amount from mean baseline left ventricular pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

12. The system of claim 1, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing arterial pressure.

13. The system of claim 12, including means responsive to the first signal and to the second signal for providing a control signal indicative of mean arterial pressure dropping by at least a predetermined amount from mean baseline arterial pressure, and wherein said means for charging and enabling discharge is responsive to the control signal.

14. The system of claim 1, including microprocessor means for developing a control signal to control the means for charging and enabling discharge of the electrical energy stored by the storage means.

15. The system of claim 1, including means responsive to the variable first signal and to the second signal for providing a control signal to control the means for charging and enabling discharge of the electrical energy stored by the storage means, the control signal being indicative of mean blood pressure at the site departing from mean baseline pressure at the site by at least a predetermined amount.

16. A system for treating a malfunctioning heart, the system comprising electrical means for sensing heart rate and producing a first control signal upon the heart rate exceeding a predetermined rate;

pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said pressure responsive sensing means for developing a first pressure-related signal representing mean baseline pressure over a period of predetermined length, means responsive to output from said sensing means for developing a second pressure-related signal representing mean current pressure over a period of given length of lesser duration than the period of predetermined length of producing a second control signal indicative of the mean current pressure departing from mean baseline pressure by at least a predetermined amount;

controllable antitachycardia pacemaking means for supplying pacing signals to the heart;

controllable cardioverting/defibrillating means including storage means for storing electrical energy and electrode means for applying electrical energy from the storage means to the heart to cardiovert or to defibrillate same;

control circuit means responsive to the first control signal and to the second control signal for enabling said antitachycardia pacemeaking means in response to presence of the first control signal and contemporaneous absence of the second control signal and for enabling said cardioverting/defibrillating means in response to contemporaneous presence of both the first control signal and the second control signal; and

means for discharging electrical energy stored by said storage means across said electrode means and into the heart.

17. The system according to claim 16, including means responsive to output from said electrical means for sensing heart rate for developing a discharge-synchronizing signal synchronized to an R-wave, and wherein said means for discharging electrical energy across said electrode means and into the heart includes means for synchronizing the discharge with the discharge-synchronizing signal to effect cardioversion.

18. The system according to claim 17, wherein said means for discharging electrical energy across said electrode means and into the heart effects discharge on a nonsynchronized basis, in the absence of the synchronization signal, to effect defibrillation.

19. The system according to claim 16, wherein said means for discharging electrical energy across said electrodes and into the heart effects discharge on a nonsynchronized basis to effect defibrillation.

20. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing right atrial pressure.

21. The system of claim 20, including means responsive to the first pressure-related signal and to the second pressure-related signal for providing the second control signal indicative of mean right atrial pressure increasing by at least a predetermined amount from mean baseline right atrial pressure.

22. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing right ventricular pressure.

23. The system of claim 22, including means responsive to the first pressure-related signal and to the second pressure-related signal for providing the second control signal indicative of mean right ventricular pressure increasing by at least a predetermined amount from mean baseline right ventricular pressure.

24. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing central venous pressure.

25. The system of claim 24, including means responsive to the first pressure-related signal and to second pressure-related signal for providing the second control output signal indicative of mean central venous pressure increasing at least a predetermined amount from mean baseline central venous pressure.

26. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing left atrial pressure.

27. The system of claim 26, including means responsive to the first pressure-related signal and to the second pressure-related signal for providing the second control signal indicative of mean left atrial pressure increasing by at least a predetermined amount from mean baseline left atrial pressure.

28. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing left ventricular pressure.

29. The system of claim 28, including means responsive to the first pressure-related signal and to the second pressure-related signal for providing the second control signal indicative of mean left ventricular pressure increasing by at least a predetermined amount from mean baseline left ventricular pressure.

30. The system of claim 16, wherein said pressure responsive sensing means for sensing pressure at a site in a circulatory system comprises means for sensing arterial pressure.

31. The system of claim 30, including means responsive to the first pressure-related signal and to the second pressure-related signal for providing the second control signal indicative of mean arterial pressure reaching a predetermined level below mean baseline arterial pressure, the second control signal indicating hemodynamic comprise.

32. In a method of treating a malfunctioning heart, the method including the step of sensing pressure at a site in a circulatory system, an improvement comprising determining variable mean baseline pressure from the sensed pressure over a period of predetermined length, determining mean current pressure from the sensed pressure over a period of given length of lesser duration than the predetermined period, and delivering cardioverting/defibrillating electrical energy to the heart in response to change of at least a predetermined magnitude in the mean current pressure from the mean baseline pressure.

33. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing right atrial pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and current mean right atrial pressure exceeding variable mean baseline right atrial pressure by at least the predetermined magnitude.

34. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing right ventricular pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and current mean right ventricular pressure exceeding variable mean baseline right ventricle pressure by at least the predetermined magnitude.

35. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing central venous pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and current mean central venous pressure exceeding variable mean baseline central venous pressure by at least the predetermined magnitude.

36. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing left atrial pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and current mean left atrial pressure exceeding variable mean baseline left atrial pressure by at least the predetermined magnitude.

37. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing left ventricular pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and the current mean left ventricular pressure exceeding variable mean baseline left ventricular pressure by at least the predetermined magnitude.

38. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing arterial pressure, and the method includes sensing heart rate, said step of delivering cardioverting/defibrillating electrical energy being taken upon the heart rate exceeding a given rate and mean current arterial pressure departing from the variable mean baseline arterial pressure by at least the predetermined magnitude in a decreasing direction.

39. The method of claim 32, wherein the step of sensing pressure at a site in a circulatory system comprises sensing right atrial pressure, said step of delivering cardioverting/defibrillating electrical energy being taken upon mean current right atrial pressure exceeding baseline right atrial pressure by at least the predetermined magnitude.

40. The method of claim 32, wherein the step of sensing pressure at a point in a circulatory system comprises sensing right ventricular pressure, said step of delivering cardioverting/defibrillating electrical energy being taken upon mean current right ventricular pressure exceeding mean baseline right ventricular pressure by at least the predetermined magnitude.

41. The method of claim 32, wherein the step of sensing pressure at a point in a circulatory system comprises sensing central venous pressure, said step of delivering cardioverting/defibrillating electrical energy being taken upon mean current central venous pressure exceeding mean baseline central venous pressure by at least the predetermined magnitude.

42. The method of claim 32, wherein the step of sensing pressure at a point in a circulatory system comprises sensing left atrial pressure, said step of delivering cardioverting/defibrillating electrical energy being taken upon mean current left atrial pressure exceeding mean baseline left atrial pressure by at least the predetermined magnitude.

43. The method of claim 32, wherein the step of sensing pressure at a point in a circulatory system comprises sensing left ventricular pressure, said step of delivering cardioverting/defibrillating electrical energy being taken upon mean current left ventricular pressure exceeding mean baseline left ventricular pressure by at least the predetermined magnitude.

44. The method of claim 32, wherein the step of sensing pressure at a point in a circulatory system comprises sensing arterial pressure, said step of cardioverting/defibrillating electrical energy being taken upon mean current arterial pressure departing from mean baseline arterial pressure by at least the predetermined magnitude in a decreasing direction.

45. A system for treating a malfunctioning heart, the system including means for providing cardioverting/defibrillating electrical energy, pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said pressure responsive sensing means for developing a variable signal representing mean pressure over a period of predetermined length, means responsive to output from said pressure responsive sensing means for developing a further signal representing mean pressure over a period of given length of lesser duration than the period of predetermined length, and means responsive to the variable signal and to the further signal for delivering the cardioverting/defibrillating electrical energy into the heart upon occurrence of departure of the further signal from the variable signal by at least a predetermined magnitude indicative of hemodynamic comprise.

46. A system for treating a malfunctioning heart, the system comprising electrical means for sensing heart rate and producing a first control signal whenever the rate exceeds a predetermined rate, pressure responsive means for sensing pressure at a site in a circulatory system;

means responsive to output from the pressure responsive means for developing a variable signal representing mean pressure over a period of predetermined length;

means responsive to output from the pressure responsive means for developing a further signal representing mean pressure over a period of given length of lesser duration than the period of predetermined duration;

means responsive to the variable signal and to the further signal for developing a second control signal upon departure of the further signal from the variable signal by at least a predetermined magnitude;

controllable antitachycardia pacemaking means for supplying pacing signals to the heart;

means for producing controllable cardioverting/defibrillating electrical energy;

control circuit means responsive to the first control signal and to the second control signal for enabling said antitachycardia pacemaking means upon presence of the first control signal and absence of the second control signal and for enabling said means for producing the cardioverting/defibrillating electrical energy upon contemporaneous presence of the first control signal and the second control signal.

47. In a system for treating a malfunctioning heart of a patient, the system including means for delivering electrical energy to the heart and pressure responsive means for sensing pressure at a site in a circulatory system, an improvement comprising means coupled to said pressure responsive means and responsive to output therefrom for producing a variable first signal representing mean pressure over a period of predetermined length;

means coupled to said pressure responsive means and responsive to output therefrom for producing a second signal representing mean pressure over a period of given length of lesser duration than the period of predetermined length;

means responsive to the first signal and to the second signal for producing a control signal upon occurrence of the second signal departing from the first signal by at least a given magnitude; and

means responsive to the control signal for enabling the means for delivering electrical energy to the heart.

48. A system for treating a malfunctioning heart of a patient, the system comprising pressure responsive means for sensing pressure at a site in a circulatory system;

means coupled to said pressure responsive means and responsive to output therefrom for producing a variable first signal representing mean pressure over a period of predetermined length;

means coupled to said pressure responsive means and responsive to output therefrom for producing a second signal representing mean pressure over a period of given length of lesser duration than the period of predetermined length;

means responsive to the first signal and to the second signal for producing a first control signal upon occurrence of the second signal departing from the first signal by at least a given magnitude;

means responsive to heart rate for producing a second control signal upon heart rate exceeding a given rate; and

means responsive to at least the first control signal and to the second control signal for delivering electrical energy to the heart.

49. In a method of treating a malfunctioning heart of a patient which includes sensing change in pressure at a site in a circulatory system and delivering to the patient electrical energy, an improvement comprising determining variable mean baseline pressure from the sensed pressure over a period of predetermined length, determining mean current pressure from the sensed pressure over a period of given length less than the duration of the predetermined period, and wherein the step of delivering electrical energy is taken in response to a difference of at least predetermined magnitude in the mean current pressure from the mean baseline pressure.

50. The method of claim 49, including determining heart rate, the step of delivering to the heart electrical energy being taken only upon the heart rate exceeding a given rate and the change of at least the predetermined magnitude in mean current pressure prevails.

51. A system for treating a malfunctioning heart, the system including storage means for storing electrical energy, electrode means for electrically coupling the storage means to the heart, pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said sensing means for developing a variable first signal representing mean baseline pressure over a period of predetermined length, means coupled to output from said sensing means for developing a second signal representing mean current pressure over a period of given length of lesser duration than the predetermined period, means responsive to output from the means for developing the variable first signal and from the means for developing the second signal for storing the first signal upon change in mean current pressure of at least a predetermined amount from mean baseline pressure to define a stored first signal representing mean baseline pressure at time of storing, means coupled to said mean for storing the first signal and to the means for developing the second signal and responsive to the stored first signal and to the second signal for charging and enabling discharge of the electrical energy stored by said storage means across said electrode means and into the heart upon change in the mean current pressure of at least predetermined amount from the mean baseline pressure at time of storing the first signal.

52. A system for treating a malfunctioning heart, the system comprising electrical means for the sensing heart rate and producing a first control signal upon the heart rate exceeding a predetermined rate;

pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said pressure responsive sensing means for developing a first pressure-related signal representing mean baseline pressure over a period of predetermined length, means responsive to output from said pressure responsive sensing means for developing a second pressure-related signal representing mean current pressure over a period of given length of lesser duration than the period of predetermined length, means responsive to outputs from the means for developing the first pressure-related signal representing mean baseline pressure and from the means for developing the second pressure-related signal for storing the first pressure-related signal upon change in mean current pressure of at least a predetermined amount from mean baseline pressure to define a stored first pressure-related signal representing mean baseline pressure at time of storing, means coupled to said means for storing the first pressure-related signal and to the means for developing the second pressure-related signal and responsive to outputs therefrom for producing a second control signal indicative of the mean current pressure departing by at least a predetermined amount from the mean baseline pressure at the time of storing the first pressure-related signal;

controllable antitachycardia pacemaking means for supplying pacing signals to the heart;

controllable cardioverting/defibrillating means including storage means for storing electrical energy and electrode means for applying electrical energy from the storage means to the heart to cardiovert or to defibrillate same;

control circuit means responsive to the first control signal and to the second control signal for enabling said antitachycardia pacemaking means in response to presence of the first control signal and contemporaneous absence of the second control signal and for enabling said cardioverting/defibrillating means in response to contemporaneous presence of both the first control signal and the second control signal.

53. A system for treating a malfunctioning heart, the system including means for providing cardioverting/defibrillating electrical energy, pressure responsive sensing means for sensing pressure at a site in a circulatory system, means responsive to output from said pressure responsve sensing means for developing a variable signal representing pressure over a period of predetermined length, means responsive to output from said pressure responsive sensing means for developing a further signal representing pressure over a period of given length of lesser duration than the period of predetermined length, means responsive to the variable signal and to the further signal for storing the variable signal upon change in mean current pressure of at least a given magnitude from mean baseline pressure to define a stored signal representing mean baseline pressure at time of storing the variable signal, means coupled to said means for storing the variable signal and to the means for developing the further signal and responsive to the further signal and to the stored signal for delivering the cardioverting/defibrillating electrical energy into the heart upon occurrence of departure of the further signal from the stored signal by at least a predetermined magnitude indicative of hemodynamic comprise.

54. A system for treating a malfunctioning heart, the system comprising electrical means for sensing heart rate and producing a first control signal whenever the rate exceeds a predetermined rate;

pressure responsive means for sensing pressure at a site in a circulatory system;

means responsive to output from the pressure responsive means for developing a variable signal representing pressure over a period of predetermined length, means responsive to output from the pressure responsive means for developing a further signal representing pressure over a period of given length of lesser duration than the period of predetermined duration;

means responsive to the variable signal and to the further signal for storing the variable signal upon change in mean current pressure of at least a given magnitude from mean baseline pressure to define a stored signal representing mean baseline pressure at time of storing the variable signal, means coupled to said means for storing the variable signal and to the means for developing the further signal and responsive to the further signal and to the stored signal for developing a second control signal upon departure of the further signal from the stored signal by at least a predetermined magnitude;

controllable antitachycardia pacemaking means for supplying pacing signals to the heart;

means for producing controllable cardioverting/defibrillating electrical energy;

control circuit means responsive to the first control signal and to the second control signal for enabling said antitachycardia pacemaking means upon presence of the first control signal and contemporaneous absence of the second control signal and for enabling said means for producing the cardioverting/defibrillating electrical energy upon contemporaneous presence of the first control signal and the second control signal.

55. In a system for treating a malfunctioning heart of a patient, the system including means for delivering electrical energy to the heart and pressure responsive means for sensing pressure at a site in a circulatory system, an improvement comprising means coupled to said pressure responsive means and responsive to output therefrom for producing a variable first signal representing mean pressure over a period of predetermined length;

means coupled to said pressure responsive means and responsive to output therefrom for producing a second signal representing the mean pressure over a period of given length of lesser duration than the period of predetermined length;

means responsive to the variable first signal and to the second signal for storing the first signal upon the second signal exceeding the variable first signal by at least a predetermined amount to define a stored signal representing mean pressure over a period of the predetermined length immediately preceding instant of storing;

means responsive to the stored signal and to the second signal for producing a control signal upon the second signal departing from the stored signal by at least a given magnitude; and

means responsive to the control signal for enabling the means for delivering electrical energy to the heart.

56. A system for treating a malfunctioning heart of a patient, the system comprising pressure responsive means for sensing pressure at a site in a circulatory system;

means coupled to said pressure responsive means and responsive to output therefrom for producing a variable first signal representing mean pressure over a period of predetermined length;

means coupled to said pressure responsive means and responsive to output therefrom for producing a second signal representing mean pressure over a period of given length of lesser duration than the period of substantially predetermined length;

means responsive to the variable first signal and to the second signal for storing the first signal upon the second signal exceeding the variable first signal by at least a predetermined amount to define a stored signal representing mean pressure over a period of the predetermined length immediately preceding instant of storing;

means responsive to the stored signal and to the second signal for producing a first control signal upon occurence of the second signal departing from the stored signal by at least a given magnitude;

means responsive to heart rate for producing a second control signal; and

means responsive to the first control signal and to the second control signal for delivering electrical energy to the heart.