Detecting and treating electromechanical dissociation of the heart

• US 9,814,886 B2
• Filed: 01/29/2010
• Issued: 11/14/2017
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zhou, Xiaohong, Krause, Paul G., Donofrio, William T.
• Primary Examiner(s): Wehrheim, Lindsey G
• Application Number:
  US12/697,019
• Publication Number:
  US 20100198284A1
• Time in Patent Office: 2,846 Days
• Field of Search: 607 4- 38, 607119-132, 607 2, 600373-375, 600449-450, 600481-503, 600508-528
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• 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 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/39624 Pain reduction therapy

Abstract

In some examples, an electromechanical disassociation state (EMD) of a heart of a patient can be treated by delivering electrical stimulation to a tissue site to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in an electromechanical dissociation state, where the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site. The delivery of electrical stimulation may effectively treat the EMD state of the heart, e.g., by enabling effective mechanical contraction of the heart. In another example, an electromechanical disassociation state of a heart of a patient can be treated by determining autonomic nervous system activity associated with a detected EMD state of the heart of a patient, and delivering electrical stimulation therapy to the patient based on the determined autonomic nervous system activity of the patient associated with the EMD state.

Claims

1. A method comprising:

sensing at least one physiological parameter of a patient;

determining whether a heart of the patient is in an electromechanical dissociation state based on the at least one sensed physiological parameter; and

delivering electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electromechanical dissociation state,

wherein the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site.

2. The method of claim 1, wherein the tissue site comprises at least one of an efferent nerve site or an afferent nerve site.

3. The method of claim 1, wherein the tissue site comprises a spinal cord of the patient.

4. The method of claim 1, wherein the tissue site comprises a tissue proximate to one or more thoracic segments.

5. The method of claim 1, wherein delivering electrical stimulation to the tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electromechanical dissociation state comprises delivering electrical stimulation to the tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity but not excite efferent nerve activity upon determining that the heart is in the electromechanical dissociation state.

6. The method of claim 1, further comprising withholding delivery of electrical stimulation to the tissue site when the electromechanical dissociation state is not determined.

7. The method of claim 1, wherein the at least one physiological parameter of the patient comprises one or more parameters indicative of mechanical contraction of the heart.

8. The method of claim 7, wherein the at least one physiological parameter comprises at least one of blood pressure, blood flow, respiratory rate, tissue perfusion, pulsatility, blood oxygen concentration, blood sugar concentration, blood pH or blood calcium concentration.

9. The method of claim 1, wherein determining whether the heart of the patient is in the electromechanical dissociation state comprises comparing the at least one physiological parameter of the patient to a threshold value that is indicative of the electromechanical dissociation state.

10. The method of claim 1, further comprising sensing delivery of at least one of cardioversion or defibrillation therapy to the heart, wherein delivering electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electromechanical dissociation state comprises delivering the electrical stimulation within approximately 10 seconds of the delivery of the at least one of cardioversion or defibrillation therapy to the heart.

11. The method of claim 1, wherein delivering electrical stimulation to a tissue site of the patient comprises delivering relatively high frequency electrical stimulation to the tissue site for a first time period and then delivering relatively low frequency electrical stimulation to the tissue site for a second time period, wherein the first time period begins before the second time period.

12. The method of claim 11, wherein the high frequency electrical stimulation has a frequency in a range of approximately 50 hertz to approximately 100 hertz.

13. The method of claim 11, wherein the first time period is less than or approximately equal to one minute but greater than zero.

14. A medical system comprising:

a sensor that senses at least one physiological parameter of a patient;

a stimulation generator; and

a processor that determines whether a heart of the patient is in an electrical mechanical dissociation state based on the at least one sensed physiological parameter and controls the stimulation generator to deliver electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electrical mechanical dissociation state, wherein the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site.

15. The medical system of claim 14, wherein the tissue site comprises at least one of an efferent nerve site or an afferent nerve site.

16. The medical system of claim 14, wherein the processor controls the stimulation generator to deliver electrical stimulation to the tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity but not excite efferent nerve activity upon determining that the heart is in the electrical mechanical dissociation state.

17. The medical system of claim 14, wherein the processor controls the stimulation generator to withhold delivery of electrical stimulation to the tissue site when the electromechanical dissociation state is not determined.

18. The medical system of claim 14, wherein the at least one physiological parameter of the patient is indicative of mechanical contraction of the heart.

19. The medical system of claim 14, wherein the at least one physiological parameter comprises at least one of blood pressure or blood flow, respiratory rate, tissue perfusion, pulsatility, blood oxygen concentration, blood sugar concentration, blood pH, or blood calcium concentration.

20. The medical system of claim 14, wherein the processor determines whether the heart is in the electromechanical dissociation state based at least in part on a comparison of the at least one physiological parameter of the patient to a threshold value.

21. The medical system of claim 14, wherein the stimulation generator comprises a first stimulation generator, the system further comprising a second stimulation generator that delivers at least one of cardioversion or defibrillation therapy to the heart of the patient, wherein the processor controls the first stimulation generator deliver electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity within approximately 10 seconds of delivery of the at least one of cardioversion or defibrillation therapy to the heart by the second stimulation generator.

22. The medical system of claim 14, wherein the processor controls the stimulation generator to generate and deliver a relatively high frequency electrical stimulation delivered to the tissue site for a first time period immediately following a determination that the heart is in the electromechanical disassociation state and deliver a relatively low frequency electrical stimulation delivered to the tissue site for a second time period, wherein the first time period begins before the second time period.

23. The medical system of claim 22, wherein the high frequency electrical stimulation has a frequency between approximately 50 hertz to approximately 100 hertz.

24. A medical system comprising:

means for sensing at least one physiological parameter of a patient;

means for determining whether a heart of the patient is in an electrical mechanical dissociation state of a heart of the patient based on the at least one sensed physiological parameter; and

means for delivering electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electrical mechanical dissociation state,

wherein the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site.

25. The medical system of claim 24, wherein the means for delivering electrical stimulation to the tissue site delivers a relatively high frequency electrical stimulation delivered to the tissue site for a first time period immediately following a determination that the heart is in the electromechanical disassociation state and delivers a relatively low frequency electrical stimulation delivered to the tissue site for a second time period, wherein the first time period begins before the second time period.

26. A method of treating an electromechanical disassociation state of a heart of a patient, wherein the method is characterized by implanting a medical device system in a patient, where the medical device system comprises a stimulation generator and a processor that determines whether the heart of the patient is in the electrical mechanical dissociation state based on at least one sensed physiological parameter and controls the stimulation generator to deliver electrical stimulation to a tissue site of the patient to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in the electrical mechanical dissociation state, wherein the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site.

27. The method of claim 26, wherein the medical device system further comprise a sensor that generate a signal indicative of the at least one physiological parameter of the patient, wherein the processor determines whether the heart of the patient is in the electrical mechanical dissociation state based on the signal.