SYNCHRONIZATION OF VAGUS NERVE STIMULATION WITH THE CARDIAC CYCLE OF A PATIENT

• US 20090177252A1
• Filed: 03/10/2009
• Published: 07/09/2009
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Catholic Healthcare West (CommonSpirit Health (Illinois))
• Original Assignee: Catholic Healthcare West (CommonSpirit Health (Illinois))
• Inventors: Craig, Arthur D.
• Granted Patent: US 8,738,126 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/353 Detecting P-waves
• CPC Class Codes: A61B 5/355 Detecting T-waves
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36064 Epilepsy
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/3611 Respiration control stimulating respiratory organs A61N1/3601
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36178 Burst or pulse train parameters

Abstract

Disclosed herein are methods, systems, and apparatus for treating a medical condition of a patient, involving detecting a physiological cycle or cycles of the patient and applying an electrical signal to a portion of the patient'"'"'s vagus nerve through an electrode at a selected point in the physiological cycle(s). The physiological cycle can be the cardiac and/or respiratory cycle. The selected point can be a point in the cardiac cycle correlated with increased afferent conduction on the vagus nerve, such as a point from about 10 msec to about 800 msec after an R-wave of the patient'"'"'s ECG, optionally during inspiration by the patient. The selected point can be a point in the cardiac cycle when said applying increases heart rate variability, such as a point from about 10 msec to about 800 msec after an R-wave of the patient'"'"'s ECG, optionally during expiration by the patient.

Claims

1. A method of treating a medical condition in a patient comprising:

detecting at least a portion of at least one of the cardiac cycle of the patient and the respiratory cycle of the patient;

applying to a vagus nerve of the patient, in response to said detecting of at least a portion of at least one of the cardiac cycle and the respiratory cycle of the patient, a pulsed electrical signal comprising a plurality of microbursts, wherein each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second; and

wherein each microburst is separated from an adjacent microburst by an interburst period of at least 100 milliseconds.

2. The method of claim 1 wherein said detecting comprises detecting at least a portion of the cardiac cycle of the patient, said detecting further comprising determining a heart rate variability (HRV) parameter, and wherein applying said pulsed electrical signal to a vagus nerve comprises applying said pulsed electrical signal to said vagus nerve in response to determining said HRV parameter.

3. The method of claim 1, further comprising increasing a heart rate variability parameter of the patient by applying said pulsed electrical signal to said vagus nerve.

4. The method of claim 1 wherein said detecting comprises detecting at least a portion of the cardiac cycle of the patient, and further comprising

determining an inhibition phase of the cardiac cycle,

wherein applying comprises not applying said pulsed electrical signal during said inhibition phase of the cardiac cycle.

5. The method of claim 4 wherein applying said pulsed electrical signal comprises applying said pulsed electrical signal after a delay period following detection of an R-wave of the patient'"'"'s cardiac cycle, and not applying a signal for a period of from the remaining portion of the same cardiac cycle to one or more subsequent cardiac cycles.

6. The method of claim 1 wherein said detecting comprises detecting at least a portion of the cardiac cycle selected from the group consisting of a P wave, an R wave, an R-R interval, a QRS complex, a T wave and the entire PQRST cycle.

7. The method of claim 1 further comprising sensing a temperature of said patient, and wherein said applying comprises applying said pulsed electrical signal in response to said temperature.

8. The method of claim 1 further comprising applying a second pulsed electrical signal to said vagus nerve without reference to said at least one of the cardiac cycle of the patient and the respiratory cycle of the patient.

9. The method of claim 8 wherein said second pulsed electrical signal is not a microburst signal.

10. The method of claim 1 wherein said detecting comprises detecting at least a portion of the respiratory cycle of the patient, and further comprising

determining an inhibition phase of the respiratory cycle,

wherein applying comprises not applying said pulsed electrical signal during said inhibition phase of the respiratory cycle.

11. The method of claim 10 wherein applying said pulsed electrical signal comprises applying said pulsed electrical signal after a delay period following detection of the beginning of inspiration, and not applying a signal for a period of from the remaining portion of the same respiratory cycle to one or more subsequent respiratory cycles.

12. The method of claim 1 wherein said detecting comprises detecting at least a portion of the respiratory cycle of the patient using the high frequency component of the HRV power spectrum to determine when inspiration occurs.

13. The method of claim 1 wherein said detecting comprises detecting at least a portion of the cardiac cycle of the patient by sensing electrical activity on the vagus nerve and initiating the therapeutic signal when the electrical activity increases.

16. The method of claim 1 wherein applying said pulsed electrical signal comprises applying a conventional vagus nerve stimulation signal to said vagus nerve during a first time period, and applying said pulsed electrical signal comprising a plurality of microbursts to said vagus nerve during a second time period.

17. The method of claim 16 wherein applying said pulsed electrical signal comprises alternating said conventional vagus nerve stimulation signal and said microburst signal with a defined off-time in which no electrical signal is applied to the vagus nerve.

14. A method of treating a medical condition in a patient comprising,

detecting endogenous electrical activity on the vagus nerve;

applying to a vagus nerve of the patient, in response to said detecting of endogenous electrical activity on the vagus nerve, a pulsed electrical signal comprising a plurality of microbursts, wherein each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second; and

wherein each microburst is separated from an adjacent microburst by an interburst period of at least 100 milliseconds.

15. The method of claim 14 where applying said pulsed electrical signal comprises supplementing endogenous vagal activity relevant to the patient'"'"'s medical condition.

18. A system for treating a medical condition in a patient comprising:

a sensor capable of sensing at least a portion of at least one of the cardiac cycle of the patient and the respiratory cycle of the patient;

a lead assembly comprising at least one electrode capable of being coupled to a vagus nerve of a patient;

an implantable medical device coupled to said lead assembly and said sensor and comprising;

a detection unit coupled to said sensor for detecting at least a portion of at least one of the cardiac cycle of the patient and the respiratory cycle of the patient;

a controller for controlling the operation of the implantable medical device;

a stimulation unit capable of generating and delivering a pulsed electrical signal comprising a plurality of microbursts to said at least one electrode in response to said detection unit detecting at least a portion of at least one of the cardiac cycle and the respiratory cycle of the patient, wherein each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second; and

wherein each microburst is separated from an adjacent microburst by an interburst period of at least 100 milliseconds.

19. A method of treating a medical condition in a patient comprising;

detecting at least a portion of the respiratory cycle of the patient;

applying to a vagus nerve of the patient, in response to said detecting of a portion of the respiratory cycle of the patient, a pulsed electrical signal comprising a plurality of microbursts, wherein each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second; and

wherein each microburst is separated from an adjacent microburst by an interburst period of at least 100 milliseconds.