JP6000535B2 - Stimulus control device, stimulus generator, and nerve stimulation system - Google Patents

Description

The present invention, stimulation control device, more particularly, with stimulation control device for controlling the stimulus generating device for generating a stimulation signal for stimulating a nerve, and stimulus generation equipment provided therewith, as well as the stimulator Relates to a neural stimulation system.

  Conventionally, as a method for treating tachycardia, it is known to regulate the heart rate by stimulating the vagus nerve, which is one of parasympathetic nerves. Patent Document 1 describes a heart treatment device used for such treatment.

The heart treatment device described in Patent Literature 1 includes a timer for measuring atrioventricular conduction time, and adjusts the parameter of the nerve stimulation signal in response to the output of the timer.
For example, the parameter is adjusted so that the stimulation energy of the nerve stimulation signal increases when the output of the timer is smaller than a predetermined value, and the stimulation energy of the nerve stimulation signal decreases when the output of the timer is larger than the predetermined value. It is supposed to adjust.

JP 2006-280588 A

By the way, as parameters of nerve stimulation signals, voltage (or current), pulse width, frequency, duration, selection of signal waveform, etc. are generally known, and increasing any of these increases stimulation energy. Can do.
However, Patent Document 1 does not describe how the parameters are specifically adjusted.

  Although the details will be described later, the inventor of the present invention indicates that even if the amount of stimulation energy applied to the heart is the same, the response of the living body is not necessarily the same if the values of the above parameters are different. I found it. This indicates that there can be a nerve stimulation signal having a more suitable parameter for the living body even with the same energy amount, and the stimulation that can optimize the parameter of the nerve stimulation signal from such a viewpoint. A generator is desired.

The present invention was made in view of the circumstances as described above, stimulation control device capable of suitably adjusting the parameters of the generated neural stimulation signal for more biological, and to provide a stimulus generation equipment With the goal.
Another object of the present invention is to provide a nerve stimulation system capable of performing treatment using a nerve stimulation signal whose parameters are more suitably adjusted for a living body.

  A first aspect of the present invention is a stimulus control device that controls a stimulus generation device that generates a nerve stimulation signal based on a signal generation parameter, and includes a control unit that adjusts the signal generation parameter, and the control unit includes: Comparing the atrioventricular conduction time of the patient after applying the neural stimulation signal to the patient with a reference atrioventricular conduction time, and when the atrioventricular conduction time is not increased with respect to the reference atrioventricular conduction time Among the signal generation parameters, the pulse width is increased.

The controller compares the RR interval of the patient after applying the neural stimulation signal to the patient with a reference RR interval, and the RR interval increases with respect to the reference RR interval. The maximum voltage value among the signal generation parameters may be decreased.
Further, the control unit may increase a maximum voltage value among the signal generation parameters when the value of the atrioventricular conduction time is equal to or less than a predetermined lower limit value.
Further, the control unit may decrease the pulse width when the value of the atrioventricular conduction time is equal to or greater than a predetermined upper limit value.

  According to a second aspect of the present invention, there is provided a stimulus generator comprising the stimulus control device of the present invention and a stimulus generator that generates the nerve stimulus signal.

  According to a third aspect of the present invention, there is provided a stimulus generating apparatus according to the present invention, a living body information detecting unit that is connected to the patient and is attached to the patient and acquires the patient's biological information, and the stimulus generating apparatus. A nerve stimulation system comprising: a nerve stimulation unit connected to and attached to the patient and applying the nerve stimulation signal to the patient.

According to the stimulation control device and stimulus generation equipment of the present invention, it is possible to suitably adjust the parameters of the generated neural stimulation signal for more biological.
Further, according to the nerve stimulation system of the present invention, it is possible to perform treatment using a nerve stimulation signal whose parameters are more suitably adjusted for a living body.

It is a mimetic diagram showing composition of a nerve stimulation system concerning a first embodiment of the present invention. It is a flowchart which shows the flow of the basic operation | movement of the same nerve stimulation system. It is a flowchart which shows the detailed flow of a parameter adjustment process. It is a flowchart which shows the detailed flow of the parameter adjustment process in the nerve stimulation system of 2nd embodiment of this invention. It is a flowchart which shows the detailed flow of the parameter adjustment process in the nerve stimulation system of the modification of this invention.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a schematic diagram showing a nerve stimulation system 1 of the present embodiment. The nerve stimulation system 1 stimulates the vagus nerve to treat tachycardia, chronic heart failure, and the like. The nerve stimulation system 1 generates a nerve stimulation signal based on predetermined parameters, and is connected to the stimulation generator 10. And a biological information detection unit 20 and a nerve stimulation unit 30 that are attached to the living body.

  The stimulus generator 10 is a stimulus generator of the present invention, and includes a control unit 11 that adjusts a generated nerve stimulus signal by a predetermined method, and a stimulus generator 14 that generates a stimulus signal. The control unit 11 includes a timer 12 and a memory 13. The control unit 11 estimates the effect of nerve stimulation based on biological information obtained from the biological information detection unit 20, and generates stimulation by adjusting the parameters of the nerve stimulation signal. The signal generation in the unit 14 is controlled. The stimulus generation unit 14 sends the stimulus signal to the nerve stimulation unit 30 according to the parameter of the nerve stimulation signal adjusted by the control unit 11. The details of the method for adjusting the nerve stimulation signal by the control unit 11 will be described later.

  The biological information detection unit 20 is attached to a living body such as a patient and acquires biological information such as an electrocardiographic waveform. The specific configuration of the biological information detection unit can be appropriately selected from known configurations according to the acquired biological information. Specifically, an ICD, an electrocardiogram monitor, or the like can be used as the biological information detection unit. Also, the attachment site may be the body surface or in a living body such as the heart, and may be set as appropriate in consideration of the type of biological information, required accuracy, and the like. The biological information detection unit 20 of the present embodiment uses the RR interval and the atrioventricular conduction time (hereinafter sometimes referred to as “PQ time”) in the electrocardiographic waveform in the control unit 11 as described later. As long as an electrocardiogram waveform can be acquired, the specific configuration and the mounting position are not particularly limited. Further, the RR interval and the atrioventricular conduction time are calculated by the control unit based on the acquired electrocardiographic waveform, and numerical values are calculated.

  The nerve stimulation unit 30 is attached to a living body such as a patient and applies the nerve stimulation signal generated by the stimulation generation unit 14 to the living body. Similar to the biological information detection unit, the specific configuration of the nerve stimulation unit can be appropriately selected from known configurations having electrodes. For the attachment site as well, for example, when stimulating the vagus nerve as in this embodiment, the body surface near the carotid artery, the superior vena cava that runs parallel to the vagus nerve, etc. May be selected.

The nerve stimulation system 1 configured as described above is used by attaching the biological information detection unit 20 and the nerve stimulation unit 30 to predetermined locations of a patient and operating the stimulation generator 10.
FIG. 2 is a flowchart showing the basic operation of the nerve stimulation system. In step S <b> 10, the control unit 11 determines whether or not the execution flag for performing nerve stimulation is 1. The execution flag indicates that the heart rate or RR interval detected by the biological information detection unit 20 is a value within a predetermined range, and it is detected that tachycardia is occurring, or the patient, doctor, etc. based on subjective symptoms Is set to 1 when a predetermined operation is performed on the stimulus generator 10 so as to perform nerve stimulation. If the determination in step S10 is yes, the process proceeds to step S20. If the determination is NO, the process returns to the beginning, and step S10 is repeated at a predetermined interval.
In addition, as a condition for the execution flag to be 1, a known various determination method including a general diagnosis criterion for tachycardia or the like may be used singly or in combination.

In step S20, the stimulus generator 14 generates a nerve stimulus signal based on a predetermined parameter. The generated nerve stimulation signal is applied from the nerve stimulation unit 30 to the vagus nerve that is the target site, and stimulation of the vagus nerve is executed. The parameter at this time is a default parameter set in the stimulus generation unit 14 if it is the first nerve stimulation after the operation, and is a parameter at the time of the previous nerve stimulation execution in the case of the second or later nerve stimulation. In some cases.
Note that this default parameter is a numerical value set by a doctor or the like according to the patient, or when an applied energy value guide is indicated, a value near the median value of each value is set, etc. It is determined by selecting a set value in a value considered as a value in accordance with the selected machine setting, or setting it as the lowest value in the value considered as a value before adjustment.
Note that the RR interval and the PQ time immediately before execution of step S20 are stored in the memory 13 for use in step S30 as reference biometric information to be described later.

  In step S30, a parameter for generating a nerve stimulation signal (hereinafter referred to as “signal generation parameter”) is adjusted based on information from the biological information detection unit 20 after the nerve stimulation performed in step S20. (Parameter adjustment process). The detailed flow of the parameter adjustment process will be described later.

In subsequent step S40, the control unit 11 determines whether or not the execution flag is 0 (zero). The execution flag is a stimulus when the heart rate or RR interval detected by the biological information detection unit 20 falls within a predetermined range and it is detected that the heart rate is normalized, or when the patient or doctor stops the nerve stimulation. It is set to 0 when a predetermined operation is performed on the generator 10. For this setting, similar to step S10, various known determination methods may be used singly or in combination.
If the determination in step S40 is YES, the series of processing ends, and after the predetermined time has elapsed, the determination in step S10 is performed again. If the determination is NO, the process returns to step S20, and nerve stimulation is performed again. This neural stimulation is executed based on the parameters updated in step S30.

FIG. 3 is a flowchart showing a detailed flow of the parameter adjustment step S30.
In step S <b> 31, the control unit 11 calculates the RR interval and the PQ time based on the biological information after the nerve stimulation executed acquired by the biological information detection unit 20 and the count value of the timer 12. The RR interval and the PQ time may be calculated for one beat acquired at a predetermined timing after the nerve stimulation is performed, and the values may be adopted, or an average value of several beats may be used. The calculated RR interval and PQ time are stored in the memory 13.

In step S <b> 32, the control unit 11 compares the calculated RR interval with the reference RR interval derived from the reference biological information, and determines whether the RR interval has increased after the nerve stimulation has been performed. Determine. When the determination is YES, the control unit 11 determines that nerve stimulation by the nerve stimulation signal is too strong, and the process proceeds to step S34. In step S34, the control unit 11 updates the maximum voltage value among the current signal generation parameters so as to decrease by a predetermined value, for example, 500 millivolts (mV). Here, the reference RR interval is a value set in the control unit 11, and is a value that is stored in the control unit after obtaining a numerical value that is determined in advance by a diagnosis or the like as an optimal numerical value of the user. is there.
The determination of whether or not the RR interval has increased may be made by a simple comparison. For example, a threshold value such as 15 milliseconds (msec) or 5% of the reference RR interval is set, and the threshold value is exceeded. It may be defined that the RR interval is extended with an increase or an increase rate. In the present embodiment, it is determined that “increased” when the RR interval increases by 5% or more with respect to the reference RR interval. This is often considered effective when the heart rate is reduced by 10% or more when measuring the nerve stimulation effect, but when the RR interval is extended by 10% or more, side effects actually occur. It is considered that there are many.
If the determination is NO, the process proceeds to step S33.

In step S33, the control unit 11 compares the calculated PQ time with the standard atrioventricular conduction time (standard PQ time) derived from the reference biological information, and determines whether or not the PQ time has increased after the nerve stimulation has been performed. Determine. The determination as to whether or not the PQ time has increased may be made by simple comparison as with the RR interval, or a threshold value may be set and defined to be extended with an increase or increase rate equal to or greater than the threshold value. In this embodiment, considering that the value of the PQ time is smaller than the value of the RR interval, it is determined that the PQ time has increased by 10% or more with respect to the reference PQ time. .
If the determination is YES, the control unit 11 determines that adjustment of the signal generation parameter is unnecessary, and ends the series of processes. When the determination is NO, the control unit 11 determines that nerve stimulation by the nerve stimulation signal is insufficient, and the process proceeds to step S35. In step S35, the control unit 11 updates the pulse width value among the current signal generation parameters so as to increase by a predetermined value, for example, 100 msec.

The above is the content of the parameter adjustment step S30 in the present embodiment. This control mode is based on the following findings found by the inventors through animal experiments and the like.
The nerve stimulation signal is composed of a plurality of unit pulses having a predetermined maximum voltage value and a duration (pulse width). In order to increase the amount of electrical energy of the nerve stimulation signal, the maximum voltage of the nerve stimulation signal may be increased, or the pulse width which is the duration of the unit pulse may be increased, but the energy amount is the same. Even when the maximum voltage value is increased and when the pulse width is increased, it is shown that the former induces a stronger biological reaction. That is, in the nerve stimulation signal, an increase in the maximum voltage value acts strongly on the living body, and an increase in pulse width acts gently.
The purpose of vagus nerve stimulation is to normalize tachycardia, which is accompanied by an increase in the RR interval, but the nerve stimulation that directly causes an increase in the RR interval is too strong for the living body, It was shown that side effects such as cough and convulsions caused by irritation may occur. Such a side effect is not preferable because there is a possibility that the heart rate may be increased by another mechanism, and there is a possibility that the patient falls over the end of treatment. On the other hand, even if the atrioventricular conduction time increases, the above-mentioned side effects are unlikely to occur and there is a slight time lag, but after the atrioventricular conduction time increases, the RR interval gradually increases and the tachycardia calms down. Turn into.
Therefore, the control method of the stimulus generator by the control unit 11 of the present embodiment aims to increase the atrioventricular conduction time without directly increasing the RR interval by nerve stimulation, and the amount of energy of the nerve stimulation signal. In order to increase the pulse width, the pulse width is exclusively increased.

  Steps S20 and S30 are usually performed within a predetermined unit time (for example, 1 minute) as a series of steps. Among them, the nerve stimulation in step S20 is performed using a part of unit time (for example, 10 seconds), and therefore the parameter adjustment step S30 is performed using the remaining part of the unit time.

  As described above, according to the nerve stimulation system 1 including the stimulation generator 10 of the present embodiment, the control unit 11 compares the PQ time after nerve stimulation with the reference PQ time in the parameter adjustment step S30. When it is determined that the PQ time has not increased, adjustment is made to increase the pulse width among the signal generation parameters. Therefore, the energy amount of the nerve stimulation signal can be increased while suppressing an excessive reaction of the living body. As a result, treatment can be performed by appropriately adjusting the amount of energy of the nerve stimulation signal while suppressing the occurrence of side effects such as cough and convulsions.

  In addition, the control unit 11 compares the RR interval after nerve stimulation with the reference RR interval, and adjusts the signal generation parameter so as to decrease the maximum voltage value when it is increasing. Can be quickly relieved, the occurrence of side effects can be suppressed, or the side effects that have occurred can be eliminated quickly.

  Further, the control unit 11 compares the atrioventricular conduction time before and after the nerve stimulation, and when not increasing, adjusts the RR interval before and after the nerve stimulation in order to adjust the signal generation parameter to increase the pulse width. Even in a state in which no change is observed, it is possible to appropriately adjust the signal generation parameter by accurately grasping the response of the heart to the nerve stimulation signal.

In the present invention, the reference RR interval and the reference PQ time can be obtained by the same method as the RR interval and the PQ time after nerve stimulation. That is, a value of one beat acquired at a predetermined timing may be adopted, or an average value of several beats may be used.
In the present embodiment, when the maximum voltage value is decreased, the maximum voltage value may be decreased by a predetermined value preset in the control unit. This predetermined value is preferably set within a range of 0.1 V to 0.5 V, for example.

  Next, a second embodiment of the present invention will be described with reference to FIG. The difference between this embodiment and the first embodiment is the details of the parameter adjustment process. In the following description, the same components as those already described are denoted by the same reference numerals and redundant description is omitted.

  The nerve stimulation system of the present embodiment has the same basic configuration as that of the nerve stimulation system 1 of the first embodiment, and differs only in the contents of the parameter adjustment process executed by the control unit 11. That is, since the control unit 11 performs the parameter adjustment step S60 instead of the parameter adjustment step S30, the details of the parameter adjustment step S60 will be described below.

  FIG. 4 is a flowchart showing a detailed flow of the parameter adjustment step S60. The contents of steps S31, S32, and S34 are the same as in the first embodiment. If the determination in step S32 is no, the process proceeds to step S61.

  In step S61, the control unit 11 determines whether or not the calculated PQ time is equal to or less than a predetermined lower limit value. When this determination is YES, the control unit 11 estimates that the therapeutic effect is hardly expected even if nerve stimulation is continued with the current signal generation parameter. Thereafter, the process proceeds to step S63, and the control unit 11 increases the maximum voltage value among the signal generation parameters by a predetermined value. If the determination is NO, the process proceeds to step S33.

The contents of steps S33 and S35 are the same as in the first embodiment. If the determination in this step is yes, the process proceeds to step S62.
In step S62, the control unit 11 determines whether or not the calculated PQ time is equal to or greater than a predetermined upper limit value. When this determination is YES, the control unit 11 estimates that the effect of nerve stimulation is slightly strong with the current signal generation parameter. Thereafter, the process proceeds to step S64, and the control unit 11 decreases the pulse width of the signal generation parameters by a predetermined value.

  The lower limit value in step S61 and the upper limit value in step S62 may be appropriately set in consideration of the patient's condition and characteristics. In the present embodiment, the lower limit value is set to 120 msec and the upper limit value is set to 220 msec in consideration of a general normal range of PQ time.

In the nerve stimulation system and the stimulation generator of this embodiment, as in the first embodiment, treatment can be performed by appropriately adjusting the amount of energy of the nerve stimulation signal while suppressing the occurrence of side effects such as cough and convulsions. .
In the present embodiment, in the parameter adjustment step S60 performed by the control unit 11, whether or not to increase / decrease the maximum voltage value or increase / decrease the pulse width is determined based on the calculated PQ time after nerve stimulation and the upper limit value. Further, since it is performed based on the comparison with the lower limit value, it is possible to perform treatment by performing finer parameter adjustment and generating a nerve stimulation signal more suitable for the living body.

  The embodiments of the present invention have been described above. However, the technical scope of the present invention is not limited to the above-described embodiments, and the combinations of the components or the components may be changed without departing from the spirit of the present invention. It is possible to make various changes to or delete them.

  For example, in each of the above-described embodiments, an example in which the maximum voltage value is decreased when the RR interval increases after nerve stimulation has been described, but this is not essential to the present invention. For example, as in the modification shown in FIG. 5, when the determination in step S32 is YES, instead of decreasing the maximum voltage value in step S34, the pulse width is decreased in step S36, thereby reducing the nerve stimulation signal. The amount of energy may be reduced.

Further, in each of the above-described embodiments, the example in which the reference RR interval and the reference PQ time in the parameter adjustment process are acquired based on the reference biometric information has been shown. The RR interval and the reference PQ time may be set and stored in advance in the memory, and the control unit may make a determination by comparing them with the value after nerve stimulation.
Alternatively, two RR intervals and PQ times after nerve stimulation within the same unit time are extracted, and the earlier value in time series is compared and determined as the reference RR interval and reference PQ time. May be.

  Further, when calculating the RR interval and PQ time after nerve stimulation, values during application of the nerve stimulation signal may be sampled. Thereby, it is also possible to make a determination while taking into account the reaction of the living body at the initial stage of nerve stimulation performed for a certain time.

  Moreover, the stimulus generator of the present invention is not necessarily distributed as a nerve stimulation system including a biological information detection unit and a nerve stimulation unit. That is, it is also possible to separately acquire and connect a conventional lead capable of acquiring an electrocardiogram waveform, a nerve stimulation electrode, and the like to the stimulation generator alone and use them as a biological information detection unit and a nerve stimulation unit.

Furthermore, the merit of the present invention can also be enjoyed by using a storage medium or the like in which the control method of the present invention is programmed and incorporating it in a control unit of a stimulus generator that can change the maximum voltage value and pulse width. is there.
It is also possible to enjoy the advantages of the present invention by attaching a unit including a microcomputer or the like that exhibits only the function of the control unit described above to a general stimulus generator as the stimulus control device of the present invention. It is.

DESCRIPTION OF SYMBOLS 1 Neural stimulation system 10 Stimulation generator 11 Control part 14 Stimulation production | generation part 20 Biological information detection part 30 Neural stimulation part

Claims (6)

A stimulation control device that controls a stimulation generator that generates a nerve stimulation signal based on a signal generation parameter,
A controller for adjusting the signal generation parameter;
The controller is
Comparing the patient's atrioventricular conduction time after applying the neural stimulation signal to the patient with a reference atrioventricular conduction time;
The stimulation control device according to claim 1, wherein when the atrioventricular conduction time is not increased with respect to the reference atrioventricular conduction time, a pulse width is increased among the signal generation parameters. The controller is
Comparing the RR interval of the patient after applying the neural stimulation signal to the patient with a reference RR interval;
2. The stimulation control apparatus according to claim 1, wherein a maximum voltage value among the signal generation parameters is decreased when the RR interval is increased with respect to the reference RR interval.   The stimulation control device according to claim 2, wherein the control unit increases a maximum voltage value among the signal generation parameters when the value of the atrioventricular conduction time is equal to or less than a predetermined lower limit value. .   The stimulation control device according to claim 3, wherein the control unit decreases the pulse width when the value of the atrioventricular conduction time is equal to or greater than a predetermined upper limit value. The stimulus control apparatus according to any one of claims 1 to 4,
A stimulation generator for generating the neural stimulation signal;
A stimulus generator characterized by comprising: A stimulus generator according to claim 5;
A biological information detection unit connected to the stimulus generator and attached to the patient to obtain biological information of the patient;
A nerve stimulation unit connected to the patient connected to the stimulation generator and applying the nerve stimulation signal to the patient;
A nerve stimulation system comprising:

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