JP4812319B2 - Nerve stimulation intensity setting device and heart treatment device - Google Patents

Description

  The present invention relates to a device used for heart treatment based on vagus nerve stimulation, and more particularly, to a nerve stimulation intensity setting device for optimally setting the stimulation strength to the vagus nerve and a heart treatment device incorporating the device.

  Sudden deaths, especially those caused by heart disease, are called sudden cardiac deaths, and about 50,000 people a year in Japan. The direct cause of sudden cardiac death is the occurrence of ventricular tachycardia or ventricular fibrillation, which is called lethal arrhythmia, which causes hemodynamic failure. Ventricular tachycardia is a state in which the ventricles are jerking abnormally fast, and ventricular fibrillation is the excitement of the individual muscle fibers that make up the ventricles, and the entire ventricle trembles in small increments. It is a state. When such ventricular tachycardia or ventricular fibrillation occurs, the pump function of the heart is reduced or lost, and the necessary blood volume cannot be delivered to the whole body. As a result, loss of consciousness is associated with a decrease in cerebral blood flow, and death may occur if appropriate measures are not taken immediately.

  By the way, although the cardiac activity is controlled by the autonomic nervous system, the autonomic nervous system includes the sympathetic nervous system and the parasympathetic nervous system, and the parasympathetic nervous system of the heart is the vagus nerve. When the sympathetic nerve activity increases (tense), the heart activity (heart rate and cardiac output) increases, and when the vagus nerve activity increases, the heart activity (heart rate) decreases. The activities of the sympathetic nerve and vagus nerve are normally antagonized, but when the balance is lost due to disease or the like, arrhythmia is likely to occur due to increased automatic ability and shortened refractory period in the myocardial stimulation conduction system. In particular, in patients with organic heart diseases such as myocardial infarction and cardiomyopathy, the activity of the vagus nerve is significantly reduced and the activity of the sympathetic nerve is increased. Combined with increased sympathetic nerve activity, the possibility of lethal arrhythmia is very high.

It is known that electrical stimulation of the vagus nerve acts preventively against such fatal arrhythmias. Electrical stimulation of the vagus nerve compensates for reduced vagal activity and acts on afferents to suppress sympathetic tone. In addition, a decrease in heart rate (increased heart rate interval) associated with electrical stimulation of the vagus nerve decreases myocardial oxygen consumption, prevents or improves oxygen deficiency at the site of myocardial injury, It is known to prevent the occurrence of myocardial infarction and the accompanying fatal arrhythmia. In addition, stabilization of the heart rate by controlling electrical stimulation of the vagus nerve is considered to make fatal arrhythmia less likely by making the distribution of the refractory period of the heart uniform.
Recently, it has been proposed to treat ventricular arrhythmia by performing electrical stimulation of the vagus nerve using such an action (see, for example, Patent Document 1). In this proposal, when a tachyarrhythmia is detected, an activation current from a current generator for nerve stimulation is sent to the vagus nerve, and fibrillation of the heart is removed (defibrillation is performed).

  An apparatus that detects arrhythmia in response to the activity of a nerve signal that transmits information from the autonomic nervous system to the heart has also been proposed (see, for example, Patent Document 2). This arrhythmia detection device has a sensor for detecting neural activity and a comparator having a threshold value that forms a condition for the presence of arrhythmia. This comparator uses an output signal indicating the occurrence of arrhythmia as a condition of neural activity. Output depending on whether or not they match. That is, as soon as chronic fibrillation or other dangerous tachyarrhythmia is detected from changes in autonomic nervous system activity, the vagus nerve is lightly activated for 5 seconds. When the return to the normal state is detected, the treatment is terminated, but when the abnormal state of the heart is continuously detected, the treatment is continued, and if sympathetic block is advantageous, the stellate ganglion is used. Done for a few seconds. When the heart activity falls below a predetermined rate due to the current being supplied to the vagus and sympathetic nerves, the pacemaker block automatically initiates stimulation to the heart, thereby attempting to maintain or repair a normal heartbeat It is.

However, the inventions described in Patent Document 1 and Patent Document 2 both prevent tachyarrhythmia by supplying an activating current to the vagus nerve and / or sympathetic nerve. There is a problem that an optimal control mechanism is not provided, and a desired effect cannot be maintained or a side effect occurs.
JP-A-8-38625 JP-A-8-52121

  Excessive stimulation of the vagus nerve reduces the excitability of the nerve cell membrane at the interface between the vagus nerve and the stimulating electrode, and depletes the neurotransmitter acetylcholine at the nerve ending to maintain the desired effect continuously Made it difficult. Physiologically, discomfort, discomfort, shortness of breath, and fatigue due to cardiac suppression are the effects on organs other than the heart. There were problems such as paralysis, dyspnea, and chewing attacks.

  In order to solve such a problem, it is necessary to optimally control the stimulation intensity of the vagus nerve so as to obtain a desired effect and at the same time, the stimulation energy for the vagus nerve becomes smaller. In general, since stimulation of the vagus nerve lowers the heart rate, it is possible to confirm the validity of the stimulation intensity setting by the degree of heart rate reduction accompanying the vagus nerve stimulation.

  However, since the heart rate is adjusted by the interaction between the sympathetic nerve and the vagus nerve, and the response varies depending on the activity state of the sympathetic nerve, the quantitative evaluation is difficult. Particularly in a state where the activity of the sympathetic nerve is low and the heart rate is reduced, even if the vagus nerve is stimulated, the decrease in the heart rate can hardly be observed. Therefore, at the time of implantation of a treatment device that requires setting and confirmation of the stimulation intensity or at the time of medical examination, it is necessary to administer a drug that enhances sympathetic nerve activity and the burden on the patient is very large.

  In addition, the stimulation of the vagus nerve prolongs the atrioventricular conduction time as a direct action, but the decrease in the heart rate accompanying the vagus nerve stimulation acts on the atrioventricular conduction in an accelerated manner. The interaction between the sympathetic nerve and the vagus nerve in this change in atrioventricular conduction time is linear addition and is independent of the activity state of the other autonomic nerve. By using such a relationship, the relationship between the vagus nerve and the atrioventricular conduction time can be quantitatively examined by measuring the atrioventricular conduction time with respect to the vagus nerve stimulation in a state where the atrium is stimulated at a predetermined rate. . The stimulation intensity of the vagus nerve stimulation used at this time is a maximal stimulation, and no device is known that optimally sets the nerve stimulation intensity using such a relationship.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a nerve stimulation intensity setting device and a heart treatment device that can optimally set the stimulation intensity of the vagus nerve. is there.

In order to solve the above problems and achieve the object of the present invention, the nerve stimulation intensity setting device and the heart treatment device of the present invention include an atrioventricular conduction time measuring means for measuring the atrioventricular conduction time of the heart, and the atrioventricular conduction time. Comparison means for comparing the measurement means output with the second predetermined time, nerve stimulation means for generating a nerve stimulation signal for stimulating the vagus nerve, and control means connected to the nerve stimulation means and the atrioventricular conduction time measurement means I have. The control means adjusts the parameter of the nerve stimulation signal in response to the output of the atrioventricular conduction time measurement means, and adjusts the parameter of the nerve stimulation signal in response to the output of the comparison means .

  Thereby, the subsequent vagus nerve stimulation intensity | strength can be optimally controlled by measuring the response of the atrioventricular conduction time with respect to vagus nerve stimulation.

In addition to the above-described means, the nerve stimulation intensity setting device and the heart treatment apparatus of the present invention further comprise an atrial stimulation means for stimulating the atrium at a predetermined rate, and a ventricular contraction detection means for detecting ventricular contraction. The atrioventricular conduction time measuring means measures the time from the atrial stimulation by the atrial stimulating means to the detection of ventricular contraction by the ventricular contraction detecting means.
In this way, the response of the atrioventricular conduction time to the vagus nerve stimulation is measured multiple times while the atrium is stimulated at a constant rate, and the vagus nerve stimulation intensity is optimally controlled by comparing each measurement result. can do.

  Moreover, the nerve stimulation intensity setting device and the heart treatment device of the present invention further include a heart rate measuring unit for measuring a heart rate in addition to the above-described units, and the control unit further includes the atrial stimulation unit and the heart rate. The rate of the atrial stimulating means is set based on the output of the heart rate measuring means connected to the measuring means.

  This controls the intensity of the vagal nerve stimulation by comparing the response of the atrioventricular conduction time to the vagal nerve stimulation with a threshold associated with the atrial stimulation rate in a state where the atrium is stimulated at a rate higher than the spontaneous rate. By doing so, the vagus nerve stimulation intensity can be optimally controlled.

Further, the nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the generation of the nerve stimulation signal is simultaneous with the stimulation of the atrium.
In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the generation of the nerve stimulation signal is performed after a predetermined delay time has elapsed from the stimulation of the atrium.

In addition, the nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the predetermined delay time from the atrial stimulation to the generation of the nerve stimulation signal is the time before the detection of ventricular contraction.
The nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the predetermined delay time from the atrial stimulation to the generation of the nerve stimulation signal is a time within the atrioventricular conduction time.
In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the control means sets a value obtained by adding a predetermined value to the output of the heart rate measurement means as the rate of the atrial stimulation means.

The nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the predetermined value is a fixed heart rate value.
The nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the predetermined value is a predetermined ratio of the measured heart rate.
Furthermore, the nerve stimulation intensity setting device and the heart treatment device of the present invention further stimulate the ventricle when the detection of ventricular contraction is not obtained even after the first predetermined time has elapsed since the generation of the atrial stimulation pulse. Ventricular stimulation means for generating a ventricular stimulation pulse is provided.

In addition, the nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the first predetermined time is extended in the heart cycle after the vagus nerve stimulation.
In addition, the nerve stimulation intensity setting device and the heart treatment device of the present invention further include a comparison unit connected to the atrioventricular conduction time measurement unit by the control unit, and adjusts the parameter of the nerve stimulation signal in response to the output of the comparison unit. Is.

The nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the second predetermined time is a function of the stimulation rate of the atrial stimulation means.

  Further, the nerve stimulation intensity setting device and the heart treatment device of the present invention adjust the parameters so that the stimulation energy of the nerve stimulation signal increases when the output of the atrioventricular conduction time measurement means is smaller than the second predetermined time. The parameter is adjusted so that the stimulation energy of the nerve stimulation signal decreases when the output of the atrioventricular conduction time measuring means is larger than the second predetermined time.

In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the atrioventricular conduction time to be compared with the second predetermined time is the atrioventricular conduction time in the heart cycle after the heart cycle to which the nerve stimulation signal is applied. It is what is.
In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the comparison means compares the atrioventricular conduction time measured in the first heart cycle with the atrioventricular conduction time measured in the second heart cycle. is there.

In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the first cardiac cycle is a heart cycle before or when the nerve stimulation signal is applied, and the second heart cycle applies the nerve stimulation signal. It is characterized by the heart cycle after.
In the nerve stimulation intensity setting device and the heart treatment device according to the present invention, the second cardiac cycle is a cardiac cycle after the Kinkaku stimulation signal is applied, and the first cardiac cycle is later than the second cardiac cycle. It is characterized by the heart cycle.

  Further, in the nerve stimulation intensity setting device and the heart treatment device of the present invention, the comparison means uses the atrioventricular conduction time (AVDl) measured in the first cardiac cycle and the atrioventricular conduction time (AVD2) measured in the second cardiac cycle. ) (AVD2−AVDl) and a third predetermined time, and the third predetermined time is a function of the stimulation rate of the atrial stimulation means.

  The nerve stimulation intensity setting device and the heart treatment device of the present invention adjust the parameter so that the stimulation energy of the nerve stimulation signal increases when the difference (AVD2-AVDl) is smaller than the third predetermined time. When the range (AVD2-AVDl) is larger than the third predetermined time, the parameter is adjusted so that the stimulation energy of the nerve stimulation signal is decreased.

  The nerve stimulation intensity setting device and the heart treatment device of the present invention are characterized in that the nerve stimulation signal is a single pulse signal or a burst signal composed of a plurality of pulses. In the nerve stimulation intensity setting device and the heart treatment device of the present invention, the adjustment of the parameter of the nerve stimulation signal includes at least one of a pulse amplitude and a pulse width.

  According to the present invention, the stimulation intensity of the vagus nerve is set by comparing the response of the atrioventricular conduction time to the vagus nerve stimulation in a state where the atrium is stimulated at a predetermined rate, so that the heart rate decreases. Even in such a state, the stimulation intensity of the vagus nerve can be set optimally, and the vagus nerve stimulation can be performed without giving a special discomfort or discomfort to the patient.

Hereinafter, an example of an embodiment of a nerve stimulation intensity setting device and a heart treatment device according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of a heart treatment device based on vagus nerve stimulation, equipped with a nerve stimulation intensity setting device according to an embodiment of the present invention.

  The heart treatment device 1 of this example detects, as its basic components, an atrial contraction detection unit 2 that detects atrial contraction, an atrial stimulation unit 3 that supplies an atrial stimulation pulse to the atrium, and a ventricular contraction. A ventricular contraction detection unit 6 and a ventricular stimulation unit 7 for supplying a ventricular stimulation pulse to the ventricle are provided. The atrial contraction detection unit 2 and the atrial stimulation unit 3 are connected to an atrial stimulation / detection electrode 5 disposed in the right atrium 11 of the heart 10 via a common atrial electrode lead 4. The ventricular contraction detection unit 6 and the ventricular stimulation unit 7 are connected to a ventricular stimulation / detection electrode 9 disposed in the right ventricle 12 of the heart 10 via a common ventricular electrode lead 8. The heart treatment device 1 itself is covered with a case of a titanium case having high biocompatibility, and is implanted under the chest or abdomen.

  In this example, a nerve stimulation unit 14 that generates a nerve stimulation pulse for stimulating the vagus nerve 13 is provided. The nerve stimulation unit 14 is wound around the vagus nerve 13 via a nerve electrode lead 15. Connected to the nerve stimulation electrode 16.

  In general, both the atrial electrode lead 4 and the ventricular electrode lead 8 are initially guided through the vena cava to the right atrium 11 of the heart 10. Then, the atrial electrode lead 4 inserted from the vena cava into the right atrium 11 is inserted so as to be hooked into the bag-like right atrial appendage protruding from the wall of the right atrium 11 with the distal end bent in a J-shape. Stimulation / detection electrode 5 is placed in contact with the inner wall of the right atrial appendage.

  The ventricular electrode lead 8 inserted into the right atrium 11 from the vena cava is further inserted into the right ventricle 12 through a tricuspid valve, which is a valve located between the right atrium 11 and the right ventricle 12, and its distal end. The ventricular stimulation / detection electrode 9 in the upper part is arranged below the right ventricle 12.

  As described above, the nerve stimulation electrode 16 is usually arranged so as to be wound around the vagus nerve 13. The region around which the nerve stimulation electrode 16 is wound is preferably a cervical region, specifically, a vagus nerve site that accompanies the center of the right external carotid artery. Further, the nerve stimulation electrode 16 can be arranged so as to stimulate the vagus nerve 13 adjacent to the blood vessel wall from inside the blood vessel. The placement region is preferably in the subclavian vein.

The heart treatment apparatus 1 of this example includes a series of control means for controlling the atrial stimulation unit 3, the ventricular stimulation unit 7, and the nerve stimulation unit 14 in addition to the above basic configuration.
This control means includes, firstly, a normal control unit 17 for controlling the heart stimulation and the vagus nerve stimulation as a normal heart treatment control, and secondly, an optimal vagus nerve stimulation intensity control. And a nerve stimulation signal parameter control unit 20 for controlling the operation.

  The switching control unit 21 performs switching control so that when one operation of the normal control unit 17 and the nerve stimulation signal parameter control unit 20 is turned on, the other operation is turned off. Normally, the operation of the normal control unit 17 is turned on and the operation of the nerve stimulation signal parameter control unit 20 is controlled to be off, but at the time of an input operation by the operation input unit 22 from the outside of the heart treatment device 1 or a timer When a switching command is input to the switching control unit 21 at every predetermined time counted by 23, the operation of the normal control unit 17 is turned off and the operation of the nerve stimulation signal parameter control unit 20 is turned on. Here, as the predetermined time measured by the timer 23, a time having as little influence on life as possible is periodically selected for the patient in which the heart treatment device 1 of the present embodiment is implanted. Specifically, it is set so that it operates every day or once a week for several minutes to about 1 hour at midnight when the patient is sleeping.

First, the configuration of the normal control unit 17 will be described.
The normal control unit 17 includes a nerve stimulation control unit 18 and a heart stimulation control unit 19. The nerve stimulation control unit 18 is connected to the nerve stimulation unit 14, and the nerve stimulation control unit 18 is connected to the nerve stimulation unit 14. To control the operation.
The cardiac stimulation control unit 19 connected to the nerve stimulation control unit 18 is connected to the atrial contraction detection unit 2, the atrial stimulation unit 3, the ventricular contraction detection unit 6, and the ventricular stimulation unit 7, respectively.

  The cardiac stimulation control unit 19 has a function of a conventional cardiac pacemaker, and based on a control signal from the nerve stimulation control unit 18, performs cardiac stimulation related to nerve stimulation treatment to the atrial stimulation unit 3 and the ventricular stimulation unit 7. Do through. In addition, the nerve stimulation control unit 18 detects the atrial contraction by the atrial contraction detection unit 2, the atrial stimulation by the atrial stimulation unit 3, the detection of the ventricular contraction by the ventricular contraction detection unit 6, and the ventricular stimulation unit. 7 receives the information of the ventricular stimulation by 7 and activates a built-in treatment control algorithm based on this information, instructs the cardiac stimulation control unit 19 to give cardiac stimulation, and gives the nerve stimulation unit 14 the vagus nerve stimulation. The instructions are given.

Next, the configuration of the nerve stimulation signal parameter control unit 20 will be described.
In the nerve stimulation signal parameter control unit 20, the output of the atrial contraction detection unit 2 is connected to one comparison input terminal of the OR circuit 24. The comparison output terminal of the OR circuit 24 is connected to a reset / start terminal of an atrial stimulation interval timer 25 for measuring an atrial stimulation interval.

  The atrial stimulation interval timer 25 and the atrial stimulation interval setting unit 26 are connected to the atrial stimulation interval comparison unit 27, and the output of the atrial stimulation interval comparison unit 27 is supplied to the atrial stimulation unit 3. This is fed back to the atrial stimulation interval timer 25 via the comparison input terminal.

  The ventricular contraction detection unit 6 is connected to a stop terminal of an AVD measurement timer 28 that measures an atrioventricular conduction time (AVD) indicating a conduction time from the atrium to the ventricle, and a start terminal of the AVD measurement timer 28 includes an OR circuit 24. The comparison output terminal is connected. The AVD measurement timer 28 and the AVD limit value storage unit 29 are connected to the AVD comparison unit 30, and are connected so that the output of the AVD comparison unit 30 is supplied to the ventricular stimulation unit 7.

The AVD measurement timer 28 is connected to the measurement AVD comparison unit 31, and the measurement AVD comparison unit 31 compares the optimal AVD reference value stored in advance with the AVD measurement value of the AVD measurement timer 28.
The measurement AVD comparison unit 31 is connected to the nerve stimulation timing unit 32, and the nerve stimulation timing unit 32 is connected to the nerve stimulation unit 14.
The measurement AVD comparison unit 31 is connected to the output of the atrial stimulation interval comparison unit 27. The measurement AVD comparison unit 31 outputs the timing of the atrial stimulation interval comparison unit 27, that is, the timing of the atrial stimulation. The nerve stimulation timing unit 32 is permitted to stimulate the vagus nerve 13 via the nerve stimulation unit 14 only once, and the stimulation of the vagus nerve 13 is prohibited at other timings.

  The measurement AVD comparison unit 31 is connected to the nerve stimulation signal parameter setting unit 33, and the nerve stimulation signal parameter setting unit 33 is connected to the nerve stimulation unit 14. The nerve stimulation signal parameter setting unit 33 determines the parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result between the optimum AVD reference value in the measurement AVD comparison unit 31 and the AVD measurement value of the AVD measurement timer 28, The parameter value is set in the stimulation unit 14.

FIG. 14 is a block diagram illustrating a detailed configuration of the measurement AVD comparison unit 31 in “comparison between AVD measurement value and second predetermined time”.
In FIG. 14, the measurement AVD comparison unit 31 includes a predetermined value storage unit 52 in which an optimal AVD reference value is stored in advance, an AVD measurement value supplied from the AVD measurement timer 28, and an optimum value read from the predetermined value storage unit 52. The comparator 51 is configured to compare the AVD reference value. The comparison unit 51 supplies the comparison result to the nerve stimulation signal parameter setting unit 33.

In addition, the measurement AVD comparison unit 31 may be an example as shown in FIG. 15 as an example of another embodiment.
FIG. 15 is a block diagram illustrating a detailed configuration of the measurement AVD comparison unit 31 in “comparison between the AVD2 measurement value / AVD1 measurement value and the second predetermined value”.

  As shown in FIG. 15, the measurement AVD comparison unit 31 includes a predetermined rate storage unit 56 in which an optimal AVD reference rate is stored in advance, and an AVD1 recording unit 53 that stores the AVD1 measurement value supplied from the AVD measurement timer 28. Similarly, the AVD2 recording unit 54 that stores the AVD2 measurement value supplied from the AVD measurement timer 28 and the relative ratio of the AVD1 measurement value read from the AVD1 recording unit 53 to the AVD2 measurement value read from the AVD2 recording unit 54 are calculated. The relative ratio of the AVD2 / AVD1 calculation unit 55 to the AVD2 measurement value calculated by the AVD2 / AVD1 calculation unit 55 to the optimum AVD reference ratio read from the predetermined ratio storage unit 56 is compared. The comparison unit 51 supplies the comparison result to the nerve stimulation signal parameter setting unit 33.

Next, the operation of the heart treatment device 1 of the present example configured as described above will be described.
First, when an atrial contraction is detected by the atrial contraction detection unit 2, the atrial stimulation interval timer 25 is started. The atrial stimulation interval setting unit 26 stores an atrial contraction interval corresponding to a heart rate higher than the self-beating heart rate, for example, 600 ms (100 times / minute), and the timer value of the atrial stimulation interval timer 25 is the atrial stimulation. When atrial contraction is detected before reaching the set value stored in the interval setting unit 26, this atrial contraction detection signal is supplied to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24, and atrial stimulation is performed. The interval timer 25 is reset again and started. On the other hand, if the atrial contraction is not detected even when the timer value of the atrial stimulation interval timer 25 reaches the setting value stored in the atrial stimulation interval setting unit 26, an output is issued from the atrial stimulation interval comparison unit 27, The right atrium 11 is stimulated via the atrial stimulation unit 3, the atrial electrode lead 4, and the atrial stimulation electrode 5. At the same time, the output of the atrial stimulation interval comparison unit 27 is supplied to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24, and the atrial stimulation interval timer 25 resets the timer value and starts again.

  The switching control unit 21 normally turns on the operation of the normal control unit 17 and turns off the operation of the nerve stimulation signal parameter control unit 20, but during the input operation by the operation input unit 22 outside the heart treatment device 1, Alternatively, when a switching command is input to the switching control unit 21 at every predetermined time counted by the timer 23, the operation of the normal control unit 17 is turned off and the operation of the nerve stimulation signal parameter control unit 20 is turned on. The switching command to the switching control unit 21 from the operation input unit 22 outside the heart treatment device 1 can be performed by the conventional telemetry communication performed between the cardiac pacemaker or the implantable cardioverter defibrillator and the programmer. This can also be realized by using a magnet as the operation input unit 22 and turning on a reed switch built in the switching control unit 21.

  The atrial contraction detection (atrial contraction detection unit 2 output) and atrial stimulation (atrial stimulation interval comparison unit 27 output) start the AVD measurement timer 28 by the OR circuit 24. Further, detection of ventricular contraction (output from the ventricular contraction detection unit 6) stops the AVD measurement timer 28. At this time, the measurement AVD comparison unit 31 acquires the AVD measurement value from the output of the AVD measurement timer 28. When the atrium contracts, either spontaneously or by stimulation, the excitement is transmitted to the ventricle through the atrioventricular conduction path connecting the atrium and the ventricle, resulting in ventricular contraction. The time from the contraction of the atrium to the contraction of the ventricle (atrioventricular conduction time) is usually about 120 ms, but when the vagus nerve 13 is stimulated, this atrioventricular conduction time is generally extended. In the AVD limit value storage unit 29, a value slightly longer than the atrioventricular conduction time extended by the stimulation of the vagus nerve 13, for example, 300 ms is stored as the first predetermined time, and the output of the AVD measurement timer 28 is the AVD. If the ventricular contraction is not detected even if the set value stored in the limit value storage unit 29 is exceeded, for example, when the stimulation intensity for the vagus nerve 13 is strong and the atrioventricular conduction is blocked, the AVD comparison is performed for safety. An output is generated from the unit 30, and the right ventricle 12 is stimulated through the ventricular stimulation unit 7, the ventricular electrode lead 8, and the ventricular stimulation electrode 9, and the ventricular contraction is ensured.

The measurement AVD comparison unit 31 compares the optimal AVD reference value (second predetermined time) stored in advance with the AVD measurement value of the AVD measurement timer 28.
As shown in FIG. 14, in the measurement AVD comparison unit 31, an optimum AVD reference value is stored in advance in the predetermined value storage unit 52, and the AVD measurement value supplied from the AVD measurement timer 28 in the comparison unit 51. Are compared with the optimum AVD reference value read from the predetermined value storage unit 52, and the comparison result is supplied to the nerve stimulation signal parameter setting unit 33.

  The measurement AVD comparison unit 31 is connected to the output of the atrial stimulation interval comparison unit 27. The measurement AVD comparison unit 31 outputs the atrial stimulation interval comparison unit 27 at the output timing, that is, the atrial stimulation timing. The nerve stimulation timing unit 32 is permitted to stimulate the vagus nerve 13 via the nerve stimulation unit 14 only once, and the stimulation of the vagus nerve 13 is prohibited at other timings.

In addition, the measurement AVD comparison unit 31 supplies a comparison result between the optimal AVD reference value and the AVD measurement value of the AVD measurement timer 28 to the nerve stimulation signal parameter setting unit 33. The nerve stimulation signal parameter setting unit 33 determines a parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result, and sets the parameter value in the nerve stimulation unit 14. For example, when the AVD measurement value is smaller than the optimum AVD reference value, the nerve stimulation signal parameter setting unit 33 increases the stimulation intensity of the vagus nerve 13 until the AVD measurement value exceeds the optimum AVD reference value. Adjust and set the parameters.
Thereby, the intensity of stimulation of the vagus nerve 13 can be optimally controlled based on the comparison between the AVD measurement value and the second predetermined time.

In addition, the measurement AVD comparison unit 31 that performs “comparison between the AVD2 measurement value / AVD1 measurement value and the second predetermined value” configured as shown in FIG. 15 operates as follows.
That is, in the measurement AVD comparison unit 31 shown in FIG. 15, the optimum AVD reference ratio is stored in advance in the predetermined ratio storage unit 56. The AVD1 recording unit 53 stores the AVD1 measurement value supplied from the AVD measurement timer 28, and the AVD2 recording unit 54 stores the AVD2 measurement value also supplied from the AVD measurement timer 28. Then, the AVD2 / AVD1 calculation unit 55 calculates the relative ratio of the AVD1 measurement value read from the AVD1 recording unit 53 to the AVD2 measurement value read from the AVD2 recording unit 54. The comparison unit 51 compares the relative ratio of the AVD1 measurement value to the AVD2 measurement value calculated by the AVD2 / AVD1 calculation unit 55 with the optimum AVD reference ratio read from the predetermined ratio storage unit 56, and compares the comparison result. This is supplied to the nerve stimulation signal parameter setting unit 33.
Thereby, the intensity of stimulation of the vagus nerve 13 can be optimally controlled based on the comparison between the relative ratio of the AVD measurement values and the second predetermined value.

The configuration and operation of the embodiment of the heart treatment device based on the vagus nerve stimulation equipped with the nerve stimulation intensity setting device of the present invention have been described above. The flowchart of FIG. This will be described in more detail based on the above.
The detailed configuration of the measurement AVD comparison unit 31 in the heart treatment device 1 shown in FIG. 1 will be described as an operation when the measurement AVD comparison unit 31 shown in FIG. 14 is used.
First, an input operation by the operation input unit 22 or a time measurement of a predetermined time by the timer 23 is input as a switching command to the switching control unit 21 to start.

  Next, the normal control unit 17 waits for an atrial stimulation instruction from the cardiac stimulation control unit 19 to the atrial stimulation unit 3 or an atrial contraction detection from the atrial contraction detection unit 2 to the cardiac stimulation control unit 19 (Step S1). S1), the process proceeds to step S2.

  Next, in accordance with the timing of the atrial stimulation instruction or the detection of atrial contraction in the cardiac stimulation control unit 19 in step S1, the switching control unit 21 turns off the operation of the normal control unit 17 and performs nerve stimulation signal parameter control. The operation of the unit 20 is turned on (step S2). Thereby, the atrial stimulation timing is matched before and after switching between the normal control unit 17 and the nerve stimulation signal parameter control unit 20.

Subsequently, in the nerve stimulation signal parameter control unit 20, the nerve stimulation signal parameter setting unit 33 supplies an initialization signal to the nerve stimulation unit 14. In the nerve stimulation unit 14, the currently set nerve stimulation signal parameter is set to the lower limit value based on this initialization signal (step S3). Next, the measurement AVD comparison unit 31 puts “0” into a counter value N for counting the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 described later (step S4).
The process from the switching command to the switching control unit 21 to the process of setting the atrial stimulation frequency N in step S4 to “0” is the initial setting process.

  Then, after resetting the atrial stimulation interval timer 25 and starting the timer (step S5), it waits for the atrial stimulation interval timer 25 to time out (step S6). When it is determined in this determination step S6 that the atrial stimulation interval timer 25 has timed out, that is, when the time measured by the atrial stimulation interval timer 25 exceeds a predetermined set value stored in the atrial stimulation interval setting unit 26, An output is generated from the stimulation interval comparison unit 27, and the right atrium 11 is stimulated by the atrial stimulation unit 3 (step S7).

Next, the measurement AVD comparison unit 31 responds to the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S7, and the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 "N + 1" is added to the counter value N for counting the counter value N and the counter value N is incremented (step S8). Subsequently, in the measurement AVD comparison unit 31, a counter value N for counting the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 by incrementing the counter value N in step S <b> 8 is set to a predetermined value (N = 3 to 5). Is determined whether or not (step S9). Steps S5 to S9 are repeated until the counter value N for counting the number of times of atrial stimulation reaches a predetermined value (N = 3 to 5). When the counter value N for counting the number of stimulations of the right atrium 11 by the atrial stimulating unit 3 becomes a predetermined value (N = 3 to 5) in the determination step S9, the process proceeds to the next step.
The process from the reset / start process of the atrial stimulation interval timer 25 in step S5 described above to the determination of the number of atrial stimulations N in step S9 is a process for keeping the heart rate constant by atrial stimulation.

  Next, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S7 is supplied to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24. The atrial stimulation interval timer 25 is reset and the timer is started (step S10). The output of the atrial stimulation interval comparison unit 27 is also supplied to the measurement AVD comparison unit 31, and the measurement AVD comparison unit 31 performs once at the output timing of the atrial stimulation interval comparison unit 27, that is, the timing of the atrial stimulation. Only the nerve stimulation timing unit 32 is allowed to stimulate the vagus nerve 13 via the nerve stimulation unit 14 (step S11), and the stimulation of the vagus nerve 13 is prohibited at subsequent timings. The nerve stimulation timing unit 32 can also stimulate the vagus nerve 13 via the nerve stimulation unit 14 simultaneously with the atrial stimulation, or after waiting for a preset delay time from the atrial stimulation, via the nerve stimulation unit 14. It is also possible to stimulate the vagus nerve 13.

  Then, it waits for the atrial stimulation interval timer 25 to time out (step S12). When the atrial stimulation interval timer 25 times out, an output is emitted from the atrial stimulation interval comparison unit 27, and the right atrium 11 is stimulated by the atrial stimulation unit 3. (Step S13).

Then, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S13 is sent to the reset / start terminal of the atrial stimulation interval timer 25 and the AVD measurement timer 28 via the OR circuit 24. 3 is reset, the atrial stimulation interval timer 25 is reset and the timer is started again (step S14), and the AVD measurement timer 28 is started (step S15). Proceed to step (A).
The process from the reset / start process of the atrial stimulation interval timer 25 in step S10 described above to the time measurement start process of the AVD measurement timer 28 in step S15 is the process of the AVD measurement pre-process.

  Next, the operation of this example following FIG. 2 will be described based on the flowchart of FIG. First, it is determined whether ventricular contraction is detected by the ventricular contraction detector 6 (step S16). If it is determined in the determination step S16 that the ventricular contraction detection unit 6 has detected the contraction of the ventricle, the AVD measurement timer 28 stops the AVD measurement, and the measurement AVD comparison unit 31 acquires the AVD measurement value at this time. (Step S17).

If it is determined in the determination step S16 that no ventricular contraction is detected from the ventricular contraction detection unit 6, it is subsequently determined whether or not the AVD measurement timer 28 has timed out (step S18). If it is determined in step S18 that the AVD measurement timer 28 has timed out, that is, the time measured by the AVD measurement timer 28 has exceeded the set value (first predetermined time) stored in the AVD limit value storage unit 29. In this case, the output signal from the AVD comparison unit 30 is sent to the ventricular stimulation unit 7 to perform ventricular stimulation (step S19). On the other hand, if the time measured by the AVD measurement timer 28 does not exceed the set value (first predetermined time) stored in the AVD limit value storage unit 29 and the AVD measurement timer 28 has not timed out, the process proceeds to decision step S16. Return and wait for the next ventricular contraction.
From the determination of the detection of ventricular contraction in step S16 described above to the processing of ventricular stimulation in step S19 is the process of acquiring the AVD measurement value.

  Next, the measurement AVD comparison unit 31 compares the optimum AVD reference value (second predetermined time) stored in advance in the predetermined value storage unit 52 with the AVD measurement value acquired in step S17 (step S20). The comparison result is supplied from the comparison unit 51 to the nerve stimulation signal parameter setting unit 33. The nerve stimulation signal parameter setting unit 33 determines a parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result, and sets the parameter value in the nerve stimulation unit 14. In determination step S20, if the AVD measurement value is smaller than the optimal AVD reference value (second predetermined time), it is determined that the effect of the vagus nerve stimulation is small, and the nerve stimulation signal parameter setting unit 33 The energy of the stimulation signal, that is, parameters such as amplitude and pulse width are increased by a predetermined amount from the currently set values and set in the nerve stimulation unit 14 (step S21).

  When the AVD measurement value exceeds the optimum AVD reference value (second predetermined time) in the determination step S20, the nerve stimulation signal parameter setting unit 33 sets the desired vagus nerve by setting the current stimulation intensity. Judgment that the effect of the stimulation is effective, the parameter value of the nerve stimulation signal is a predetermined margin than the currently set value so that the effect of the vagus nerve stimulation is ensured even if there is a change in the biological condition. Is updated with a higher value and set in the nerve stimulation unit 14 (step S22). Thereafter, the switching control unit 21 turns off the operation of the nerve stimulation signal parameter control unit 20, turns on the operation of the normal control unit 17, and returns to the normal control operation (step S23).

Thereby, the intensity of stimulation of the vagus nerve 13 can be optimally controlled based on the comparison between the AVD measurement value and the second predetermined time.
From the above-described determination process of comparing the AVD measurement values in step S20 to the switching process to the normal control in step S23 is a process of changing the nerve stimulation signal parameter based on the AVD measurement values.

  Subsequently, it waits for the atrial stimulation interval timer 25 to time out (step S24). When the atrial stimulation interval timer 25 times out, an output is output from the atrial stimulation interval comparison unit 27, and the right atrium 11 is stimulated by the atrial stimulation unit 3. (Step S25).

  Here, the measurement AVD comparison unit 31 waits for M beats until the influence of the stimulation of the vagus nerve 13 in step S11 disappears, so that the counter value M for counting the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 described later is set to “0”. "Is entered (step S26).

  Then, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S25 is the reset / start terminal of the atrial stimulation interval timer 25 and the AVD measurement timer 28 via the OR circuit 24. The atrial stimulation interval timer 25 is reset to start timing (step S27), and the AVD measurement timer 28 starts timing (step S28), and the next step (B) shown in FIG. 4 is performed. move on.

  Next, the process of this example following the process of FIG. 3 will be described based on FIG. When the AVD measurement timer 28 starts timing in step S28 of FIG. 3, the ventricular contraction detector 6 determines whether or not ventricular contraction is detected (step S29). If it is determined in this determination step S29 that the ventricular contraction detector 6 has detected the contraction of the ventricle, the AVD measurement timer 28 stops the AVD measurement (step S30). If it is determined in the determination step S29 that no ventricular contraction is detected, it is then determined whether the AVD measurement timer 28 has timed out (whether or not the first predetermined time has been exceeded) (step S31). When it is determined in this determination step S31 that the AVD measurement timer 28 has timed out, a signal is sent from the AVD comparison unit 30 to the ventricular stimulation unit 7 to stimulate the right ventricle 12 (step S32). If it is determined that the measurement timer 28 has not timed out, the process returns to determination step S29 to wait for the next ventricular contraction.

  Next, it waits for the atrial stimulation interval timer 25 to time out (step S33). When the atrial stimulation interval timer 25 times out, an output is emitted from the atrial stimulation interval comparison unit 27 to the atrial stimulation unit 3, and the atrial stimulation unit 3 The right atrium 11 is stimulated (step S34).

  Subsequently, the measurement AVD comparison unit 31 responds to the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S34, and the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 "M + 1" is added to the counter value M for counting the counter value M and the counter value M is incremented (step S35).

In the measurement AVD comparison unit 31, the counter value M for counting the number of stimulations of the right atrium 11 by the atrial stimulation unit 3 by incrementing the counter value M in step S35 is set to a predetermined value (M = 5 to 10). It is determined whether or not they are equal (step S36). If it is determined in the determination step S36 that the counter value M has not reached the predetermined value (M = 5 to 10) (C), the process returns to step S27 in FIG. Reset / start processing is performed. When it is determined in the determination step S36 that the counter value M has reached a predetermined value (M = 5 to 10) (D), the atrial stimulation in step S10 of the AVD measurement pre-process shown in FIG. Returning to the reset / start processing of the interval timer 25, the above-described steps to this step are repeated.
The process from the time-out determination of the atrial stimulation interval timer 25 in step S24 to the determination of the counter value M in step S36 is a process of waiting for M beats until the influence of the vagus nerve stimulation in step S11 is eliminated.

Next, the operation of an example in which the timing of the stimulation process of the vagus nerve 13 in step S11 and the timing of the AVD measurement value acquisition process in step S17 are different will be described based on the flowcharts shown in FIGS. As a detailed configuration of the measurement AVD comparison unit 31, an operation when the measurement AVD comparison unit 31 shown in FIG. 15 is used will be described.
Here, a different part from the flowchart shown to FIGS. 2-4 mentioned above is demonstrated, and about the same process, the same step name and process name are shown and the description is abbreviate | omitted.

The process from the start to step S104 is the same as the initial setting process from the switching command to the switching control unit 21 shown in FIG. 2 to the process of setting the atrial stimulation frequency N in step S4 to “0”.
The processing from step S105 to step S109 is performed in order to keep the heart rate constant by atrial stimulation from the reset / start processing of the atrial stimulation interval timer 25 in step S5 of FIG. 2 to the determination of the number of atrial stimulations N in step S9. It becomes the same as this process.

Here, steps after step S110 will be described.
The output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S107 is the reset / start terminal of the atrial stimulation interval timer 25 and the start of the AVD measurement timer 28 via the OR circuit 24. Then, the atrial stimulation interval timer 25 is reset to start the timer (step S110), and the AVD measurement timer 28 starts timing (step S111). The output of the atrial stimulation interval comparison unit 27 is also supplied to the measurement AVD comparison unit 31, and the measurement AVD comparison unit 31 performs once at the output timing of the atrial stimulation interval comparison unit 27, that is, the atrial stimulation timing. Only the nerve stimulation timing unit 32 is allowed to stimulate the vagus nerve 13 via the nerve stimulation unit 14 (step S112), and at a later timing, the stimulation of the vagus nerve 13 is prohibited. The nerve stimulation timing unit 32 can also stimulate the vagus nerve 13 via the nerve stimulation unit 14 simultaneously with the atrial stimulation, or after waiting for a preset delay time from the atrial stimulation, via the nerve stimulation unit 14. It is also possible to stimulate the vagus nerve 13.

Next, the ventricular contraction detection unit 6 waits for the detection of ventricular contraction (step S113). When the ventricular contraction detection unit 6 detects the ventricular contraction, the AVD measurement timer 28 stops the AVD measurement. Then, the measurement AVD comparison unit 31 acquires the AVD measurement value at this time as the AVD1 measurement value (step S114). This AVD1 measurement value is stored in the AVD1 recording unit 53 shown in FIG.
From the process of resetting / starting the atrial stimulation interval timer 25 in step S110 described above to the process of acquiring / storing the AVD1 measurement value in step S114, the AVD1 measurement value acquisition / storage in the heart cycle in which the vagus nerve 13 is stimulated is performed. It becomes a process.

  Next, the process (process after A) following the process of FIG. 5 is demonstrated based on the flowchart of FIG. First, it waits for the atrial stimulation interval timer 25 to time out (step S115). When the atrial stimulation interval timer 25 times out, an output is emitted from the atrial stimulation interval comparison unit 27, and the right atrium 11 is stimulated by the atrial stimulation unit 3. (Step S116).

  Then, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S116 is the reset / start terminal of the atrial stimulation interval timer 25 and the start of the AVD measurement timer 28 via the OR circuit 24. Then, the atrial stimulation interval timer 25 is reset to start the timer (step S117) and the AVD measurement timer 28 starts counting (step S118).

  Next, it is determined whether or not ventricular contraction is detected by the ventricular contraction detector 6 (step S119). If it is determined in this determination step S119 that the contraction of the ventricle has been detected, the AVD measurement timer 28 stops the AVD measurement, and the measurement AVD comparison unit 31 acquires the AVD measurement value at this time as the AVD2 measurement value (step S120). ). This AVD2 measurement value is stored in the AVD2 recording unit 54 shown in FIG.

  If it is determined in step S119 that no ventricular contraction is detected, it is determined whether the AVD measurement timer 28 has timed out (whether the first predetermined time has been exceeded) (step S121). When it is determined in this determination step S121 that the AVD measurement timer 28 has timed out, a signal is sent from the AVD comparison unit 30 to the ventricular stimulation unit 7 to stimulate the right ventricle 12 (step S122). If it is determined that the timer 28 has not timed out, the process returns to determination step S119 to wait for the next ventricular contraction.

  From the determination of the timeout of the atrial stimulation interval timer 25 in step S115 described above to the processing of ventricular stimulation in step S122 is an AVD2 measurement value acquisition / storage process in the next cardiac cycle in which the vagus nerve 13 is stimulated.

  Next, in the measurement AVD comparison unit 31, the optimum AVD reference ratio (second predetermined value) stored in advance in the predetermined ratio storage unit 56 and the AVD2 acquired in step S120 calculated in the AVD2 / AVD1 calculation unit 55 The relative ratio of the AVD1 measurement value acquired in step S114 to the measurement value is compared by the comparison unit 51 (step S123), and the comparison result is supplied from the comparison unit 51 to the nerve stimulation signal parameter setting unit 33. The nerve stimulation parameter setting unit 33 determines the parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result, and sets the parameter value in the nerve stimulation unit 14. If the relative ratio of the AVD2 measurement value to the AVD1 measurement value is smaller than the optimum AVD reference ratio (second predetermined value) in the determination step S123, it is determined that the effect of the vagus nerve stimulation is small, and the nerve stimulation The signal parameter setting unit 33 increases the energy of the nerve stimulation signal, that is, the parameters such as the amplitude and the pulse width by a predetermined amount from the currently set values and sets them in the nerve stimulation unit 14 (step S124).

  If the relative ratio of the AVD1 measurement value to the AVD1 measurement value is larger than the optimum AVD reference ratio (second predetermined value) in the determination step S123, the nerve stimulation signal parameter setting unit 33 The parameter value of the nerve stimulation signal is currently set so that the effect of the desired vagus nerve stimulation is judged by the setting of the stimulation intensity and the reliable vagus nerve stimulation effect is guaranteed even if there is a change in the biological situation It is updated with a value higher by a predetermined margin than the current value, and is set in the nerve stimulation unit 14 (step S125). Thereafter, the switching control unit 21 turns off the operation of the nerve stimulation signal parameter control unit 20, turns on the operation of the normal control unit 17, and returns to the normal control operation (step S126).

Accordingly, the intensity of stimulation of the vagus nerve 13 can be optimally controlled based on the comparison between the relative ratio of the AVD measurement values and the second predetermined value.
From the determination of the comparison of the relative ratio of the AVD measurement value in step S123 described above to the switching process to the normal control in step S126 is a process of changing the nerve stimulation signal parameter based on the relative ratio of the AVD measurement value.

  Then, the processing and determination from the next step S127 to step S139 are the steps from the determination of the timeout of the atrial stimulation interval timer 25 in step S24 shown in FIG. 2 to the determination of the counter value M in step S36. In the same manner as in step S112, the process waits for M beats until the influence of the vagus nerve stimulation is eliminated.

FIG. 8 is a diagram illustrating the timing of vagus nerve stimulation and AVD measurement value acquisition.
In FIG. 8, atrial stimulation (AP) is repeatedly performed at a set time interval stored in the atrial stimulation interval setting unit 26, and the vagus nerve stimulation (VNS) is performed after a predetermined delay time from the third atrial stimulation (AP). ) Is done.
2 to 4, the atrioventricular conduction time from the atrial stimulation (AP) to the ventricular contraction (VS) in the cardiac cycle following the cardiac cycle in which the vagus nerve stimulation (VNS) is performed. The intensity of stimulation of the vagus nerve 13 is controlled by comparing a certain AVD (1) with a second predetermined time. It is possible to compare the AVD (2) and AVD (3) with the second predetermined time instead of the AVD (1), but the effect of the vagus nerve stimulation on the atrioventricular conduction time is to perform the vagus nerve stimulation. AVD (1) is suitable as the atrioventricular conduction time for comparison, because the effect is the largest in the next cardiac cycle after the cardiac cycle and the effect gradually decreases in the subsequent cardiac cycles.

  In the operations of the flowcharts shown in FIG. 5 to FIG. 7, AVD (AVD), which is the atrioventricular conduction time from the atrial stimulation (AP) to the ventricular contraction (VS) in the cardiac cycle in which the vagus nerve stimulation (VNS) is performed. 0) AVD1 measurement value, AVD (1) which is the atrioventricular conduction time from the atrial stimulation (AP) to the ventricular contraction (VS) in the cardiac cycle following the cardiac cycle in which the vagus nerve stimulation (VNS) is performed By comparing the AVD2 measurement value / AVD1 measurement value and the second predetermined value as the AVD2 measurement value, the intensity of stimulation of the vagus nerve 13 is to be controlled. Here, AVD (0) represents the atrioventricular conduction time not affected by the vagus nerve stimulation (VNS), and AVD (1) represents the atrioventricular conduction time affected by the vagus nerve stimulation (VNS). Therefore, instead of AVD (0), AVD (−2) and AVD (−1), which are atrioventricular conduction times not affected by vagus nerve stimulation (VNS), can be used as the AVD1 measurement value.

Further, as a modification not shown, a difference or ratio of atrioventricular conduction time measured after the next cardiac cycle of the cardiac cycle in which vagus nerve stimulation (VNS) is performed (for example, AVD (1) −AVD (3), It is also possible to control the intensity of stimulation of the vagus nerve 13 by comparing the AVD (1) / AVD (3) and the like with a third predetermined time or a second predetermined value.
As described above, in the timing of obtaining the vagus nerve stimulation and the AVD measurement value, various combinations are possible according to other modifications (not shown) in addition to the above-described combinations.

In the above-described embodiment, an example is shown in which the intensity of stimulation of the vagus nerve 13 is optimally controlled based on the comparison between the AVD measurement value and the second predetermined time, the third predetermined time, or the second predetermined value. However, the intensity of stimulation of the vagus nerve 13 is optimal based on a comparison between the second predetermined time, the third predetermined time, or the second predetermined value corresponding to the AVD measurement value and the stimulation rate. You may make it control to.
Hereinafter, an example of control based on comparison between the AVD measurement value and the second predetermined value corresponding to the stimulation rate or the third predetermined time will be described.

FIG. 9 is a block diagram showing an example of a cardiac treatment device based on vagus nerve stimulation, which is equipped with a nerve stimulation intensity setting device according to another embodiment of the present invention.
In FIG. 9, parts corresponding to those in FIG. In FIG. 9, only the nerve stimulation signal parameter control unit 40 is different from that in FIG. 1, and the configuration of the nerve stimulation signal parameter control unit 40 will be described below.

  In the nerve stimulation signal parameter control unit 40, the output of the atrial contraction detection unit 2 is connected to one comparison input terminal of the OR circuit 24. The comparison output terminal of the OR circuit 24 is connected to the heart rate measuring unit 41 that measures the self-beat heart rate and is connected to the start terminal of the AVD measurement timer 28.

  The heart rate measurement unit 41 is connected to one input of a heart rate increment value calculation unit 42 and an addition unit 45 that calculate a predetermined ratio of the measured self-beat heart rate. The heart rate increment value calculation unit 42 and the heart rate fixed increment value storage unit 43 are both connected to the selection unit 44, and the selection unit 44 is connected to the other input of the addition unit 45. The output of the adding unit 45 is connected to an HR (heart rate) / PP (time interval of atrial contraction P wave) converting unit 46 that converts a heart rate into a time interval.

  The output of the atrial contraction detector 2 is connected to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24. The atrial stimulation interval timer 25 and the HR / PP conversion unit 46 are connected to the atrial stimulation interval comparison unit 27. The output of the atrial stimulation interval comparison unit 27 is supplied to the atrial stimulation unit 3, and the OR circuit 24 is Via the atrial stimulation interval timer 25. The output of the atrial stimulation interval comparison unit 27 is connected to the measurement AVD comparison unit 31.

  The ventricular contraction detection unit 6 is connected to the stop terminal of the AVD measurement timer 28, and the output of the nerve stimulation timing unit 32 is connected to the AVD setting unit 49. The AVD measurement timer 28 and the AVD setting unit 49 are connected to the AVD comparison unit 30, and are connected so that the output of the AVD comparison unit 30 is supplied to the ventricular stimulation unit 7.

  In addition, a first AVD storage unit 47 that stores an AVD value (for example, 150 ms) for ensuring ventricular contraction in normal atrioventricular conduction and an AVD value for securing ventricular contraction in atrioventricular conduction during vagus nerve stimulation (for example, 300 ms) is connected to the AVD setting unit 49.

  Further, a comparison value table storage unit 50 that stores an AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate is connected to the measurement AVD comparison unit 31. The output of the adding unit 45 is connected to the comparison value table storage unit 50.

  The measurement AVD comparison unit 31 uses the AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate stored in the comparison table storage unit 50 and the AVD measurement value of the AVD measurement timer 28. Compare. The measurement AVD comparison unit 31 is connected to the nerve stimulation timing unit 32, and the nerve stimulation timing unit 32 is connected to the nerve stimulation unit 14.

  The measurement AVD comparison unit 31 permits the nerve stimulation timing unit 32 to stimulate the vagus nerve 13 via the nerve stimulation unit 14 only once at the output timing of the atrial stimulation interval comparison unit 27, that is, the timing of the atrial stimulation. At the same time, stimulation of the vagus nerve 13 is prohibited at other timings.

In addition, the measurement AVD comparison unit 31 is connected to the nerve stimulation signal parameter setting unit 33. The nerve stimulation signal parameter setting unit 33 is connected to the nerve stimulation unit 14.
The measurement AVD comparison unit 31 includes an AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate stored in the comparison table storage unit 50 and the AVD measurement value of the AVD measurement timer 28. The nerve stimulation signal parameter setting unit 33 determines the parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result, and the nerve stimulation unit 14 determines the parameter. Set the value.

In the example of this embodiment, the measurement AVD comparison unit 31 performs “comparison with the second predetermined value corresponding to the stimulation rate or the third predetermined time”, and the configuration for this will be described. .
FIG. 16 is a block diagram illustrating a detailed configuration of the measurement AVD comparison unit 31 in “comparison with the second predetermined value or the third predetermined time corresponding to the stimulation rate”.

  In FIG. 16, a measurement AVD comparison unit 31 includes an AVD1 recording unit 53 that stores an AVD1 measurement value supplied from the AVD measurement timer 28, and an AVD2 recording unit 54 that stores an AVD2 measurement value supplied from the AVD measurement timer 28. Using the AVD1 measurement value read from the AVD1 recording unit 53 with respect to the AVD2 measurement value read from the AVD2 recording unit 54, the relative ratio of the AVD2 measurement value to the AVD2 measurement value or the difference between the AVD2 measurement value and the AVD1 measurement value is calculated. The comparison value calculation unit 57 to be calculated and the relative ratio of the AVD2 measurement value to the AVD2 measurement value calculated by the comparison value calculation unit 57 or the difference between the AVD2 measurement value and the AVD1 measurement value and the comparison table storage unit 50 are read out. An optimal AVD reference comparison value corresponding to the atrial stimulation rate (second predetermined value or third value) Comparing the predetermined time) and, and a comparator 51 supplies the comparison result to the neural stimulation signal parameter setting unit 33.

Next, the operation of the heart treatment device 1 of the present example configured as described above will be described.
The heart rate measurement unit 41 measures the self-beat heart rate from the detection signal of the atrial contraction of the atrial contraction detection unit 2 and supplies it to the heart rate increment value calculation unit 42, and the heart rate increment value calculation unit 42 is supplied A predetermined ratio of the self-beating heart rate is calculated from the self-beating heart rate. The predetermined rate of the self-heart rate calculated by the heart rate increment value calculation unit 42 is supplied to the addition unit 45 via the selection unit 44, and the addition unit 45 measures the measured self-heart rate and the predetermined rate. Are added, and a heart rate slightly higher than the self-heart rate is output. Note that the value added in the adding unit 45 is changed to the predetermined rate of the own heart rate from the heart rate increment value calculating unit 42 instead of the selection unit 44 and stored in the heart rate fixed increment value storing unit 43 in advance. It is also possible to use stored setting values. As for which of the heart rate increment value calculation unit 42 and the heart rate fixed increment value storage unit 43 connected to the selection unit 44 to select, one of the preset initial settings can be selected via the operation input unit 22. It is also possible to select the other. The heart rate slightly higher than the self-beating heart rate output from the adding unit 45 is converted into a time interval by the HR / P-P conversion unit 46, and then the atrial stimulation interval is used as a time-out time threshold of the atrial stimulation interval timer 25. It is supplied to the comparison unit 27.

  The atrial stimulation interval timer 25 is started by detecting the atrial contraction by the atrial contraction detection unit 2. The atrial stimulation interval comparison unit 27 is supplied with a time interval corresponding to a heart rate slightly higher than the self-beating heart rate output from the HR / P-P conversion unit 46 as a timeout time threshold value of the atrial stimulation interval timer 25. When the atrial contraction is detected before the timer value of the atrial stimulation interval timer 25 reaches a time interval corresponding to a heart rate slightly higher than the self-beating heart rate, this atrial contraction detection signal is sent via the OR circuit 24 to the atrial stimulation. Supplied to the reset / start terminal of the interval timer 25, the atrial stimulation interval timer 25 resets again and starts. On the other hand, if atrial contraction is not detected even when the timer value of the atrial stimulation interval timer 25 reaches a time interval corresponding to a heart rate slightly higher than the self-beating heart rate, an output is generated from the atrial stimulation interval comparison unit 27. The right atrium 11 is stimulated via the atrial stimulation unit 3, the atrial electrode lead 4, and the atrial stimulation electrode 5. Therefore, the atrium is stimulated at an atrial stimulation rate slightly higher than the self-beating heart rate. At the same time, the output of the atrial stimulation interval comparison unit 27 is supplied to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24, and the atrial stimulation interval timer 25 resets the timer value and starts again.

  The atrial contraction detection (atrial contraction detection unit 2 output) and atrial stimulation (atrial stimulation interval comparison unit 27 output) start the AVD measurement timer 28 by the OR circuit 24. Further, detection of ventricular contraction (output from the ventricular contraction detection unit 6) stops the AVD measurement timer 28. At this time, the measurement AVD comparison unit 31 acquires the AVD measurement value from the output of the AVD measurement timer 28. The AVD setting unit 49 selects the first AVD storage unit 47 for securing the ventricular contraction in the normal atrioventricular conduction at the timing of the nerve stimulation trigger from the nerve stimulation timing unit 32 to the nerve stimulation unit 14, and at the time of vagus nerve stimulation. Switching to selection of the second AVD storage unit 48 for ensuring ventricular contraction in atrioventricular conduction. If the ventricular contraction is not detected even if the output of the AVD measurement timer 28 exceeds the time-out time threshold of the AVD measurement timer 28 selected by the AVD setting unit 49, an output is issued from the AVD comparison unit 30 for safety. The right ventricle 12 is stimulated through the ventricular stimulation unit 7, the ventricular electrode lead 8, and the ventricular stimulation electrode 9, and the ventricular contraction is ensured.

The comparison value table storage unit 50 holds the relationship between the heart rate and the AVD reference comparison value (second predetermined value or third predetermined time), and the AVD reference comparison value corresponding to the input heart rate. (Second predetermined value or third predetermined time) is output. The adding unit 45 inputs a heart rate slightly higher than the own pulse, that is, the atrial stimulation rate, to the comparison value table storage unit 50, and an AVD reference comparison value (second predetermined value or third value) corresponding to the atrial stimulation rate. Predetermined time) is supplied from the comparison value table storage unit 50 to the measurement AVD comparison unit 31.
The measurement AVD comparison unit 31 uses the AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate stored in the comparison table storage unit 50 and the AVD measurement value of the AVD measurement timer 28. Compare.

  As shown in FIG. 16, in the measurement AVD comparison unit 31, the AVD1 recording unit 53 stores the AVD1 measurement value supplied from the AVD measurement timer 28, and the AVD2 recording unit 54 stores the AVD2 measurement value supplied from the AVD measurement timer 28. Is stored. The comparison value calculation unit 57 uses the AVD2 measurement value read from the AVD2 recording unit 54 and the AVD1 measurement value read from the AVD1 recording unit 53, and the relative ratio of the AVD1 measurement value to the AVD2 measurement value or the AVD2 measurement value The difference from the AVD1 measurement value is calculated. The comparison unit 51 calculates the relative ratio of the AVD1 measurement value to the AVD2 measurement value calculated by the comparison value calculation unit 57 or the difference between the AVD2 measurement value and the AVD1 measurement value and the atrial stimulation rate read from the comparison table storage unit 50. The corresponding optimum AVD reference comparison value (second predetermined value or third predetermined time) is compared, and the comparison result is supplied to the nerve stimulation signal parameter setting unit 33.

  The measurement AVD comparison unit 31 permits the nerve stimulation timing unit 32 to stimulate the vagus nerve 13 via the nerve stimulation unit 14 only once at the output timing of the atrial stimulation interval comparison unit 27, that is, the timing of the atrial stimulation. In addition, the stimulation of the vagus nerve 13 is prohibited at other timings.

  The measurement AVD comparison unit 31 also outputs a comparison result between the AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate and the AVD measurement value of the AVD measurement timer 28 as a nerve stimulation signal. This is supplied to the parameter setting unit 33. The nerve stimulation signal parameter setting unit 33 determines a parameter of the nerve stimulation signal for the vagus nerve 13 based on the comparison result, and sets the parameter value in the nerve stimulation unit 14.

Next, the operation of the above example will be described based on the flowcharts shown in FIGS.
Here, a different part from the flowchart shown to FIGS. 2-4 mentioned above is demonstrated, and about the same process, the same step name and process name are shown and the description is abbreviate | omitted.
The processes of Step S201, Step S202, and Step S203 from the start are the same as the processes of Step S1, Step S2, and Step S3 described in FIG. 2, and the process of Step S208 is the atrium of Step S4 described in FIG. This is the same as the process of setting the number of stimulations N to “0”.

  In step S203, after the nerve stimulation signal parameter currently set in the nerve stimulation unit 14 is initialized with the lower limit value by the initialization signal from the nerve stimulation signal parameter setting unit 33, the heart rate measurement unit 41 performs an OR circuit. The self-beating heart rate is measured from the atrial contraction detection signal of the atrial contraction detection unit 2 via 24 (step S204). Next, the self-beat heart rate measured by the heart rate measuring unit 41 is supplied to the heart rate increment value calculating unit 42, and the heart rate increment value calculating unit 42 measures the self-beat heart rate measured by the heart rate measuring unit 41. A heart rate value of a predetermined percentage of the number is calculated. The calculated heart rate value of a predetermined rate of the self-beating heart rate is supplied to the adding unit 45 via the selection unit 44, and the adding unit 45 adds the predetermined rate of the self-beating heart rate and the self-beating heart rate. Then, an atrial stimulation rate is calculated as a heart rate slightly higher than the self-heart rate (step S205). Note that the value added in the adding unit 45 is changed to the predetermined rate of the own heart rate from the heart rate increment value calculating unit 42 instead of the selection unit 44 and stored in the heart rate fixed increment value storing unit 43 in advance. It is also possible to use stored setting values.

  Subsequently, the adding unit 45 determines whether or not the atrial stimulation rate calculated in step S205 is equal to or lower than a predetermined upper limit rate (step S206). When it is determined in this determination step S206 that the atrial stimulation rate is equal to or lower than the upper limit rate, the atrial stimulation rate calculated in step S205 is converted into a time interval by the HR / PP conversion unit 46. Then, the HR / P-P conversion unit 46 supplies the converted time interval to the atrial stimulation interval comparison unit 27 as a threshold value for the timeout time of the atrial stimulation interval timer 25 (step S207). When it is determined in the determination step S206 that the atrial stimulation rate has exceeded a predetermined upper limit rate (D), in order to prevent the heart from being stimulated at a high rate, the process proceeds to step S248 in FIG. Advance to normal control.

  From the self-heart rate measurement process in step S204 to the process for setting the threshold value for the timeout time of the atrial stimulation interval timer 25 in step S207 described above, the steps of self-heart rate measurement and atrial stimulation rate setting are performed.

Next, steps after step S209 will be described.
First, the atrial stimulation interval timer 25 is reset and the timer is started (step S209). Subsequently, it is determined whether or not the atrial stimulation interval timer 25 has timed out (step S210). When it is determined in the determination step S210 that the atrial stimulation interval timer 25 has timed out, that is, the time measured by the atrial stimulation interval timer 25 supplied from the HR / PP conversion unit 46 is the time-out time of the atrial stimulation interval timer 25. When the threshold value is exceeded, an output is emitted from the atrial stimulation interval comparison unit 27, and the right atrium 11 is stimulated by the atrial stimulation unit 3 (step S212).

  Further, in the determination step S210, the atrial stimulation interval timer 25 times out without exceeding the time-out threshold value of the atrial stimulation interval timer 25 supplied from the HR / P-P converter 46 in the time measured by the atrial stimulation interval timer 25. If not, it is determined whether atrial contraction is detected by the atrial contraction detector 2 (step S211). If it is determined in this determination step S211 that the contraction of the atrium has been detected, the process returns to the self-heart rate measurement process in step S204. If it is determined in step S211 that no atrial contraction has been detected, the process returns to the time-out determination process of the atrial stimulation interval timer 25 in step S210.

  Next, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S212 is supplied to the reset / start terminal of the atrial stimulation interval timer 25 via the OR circuit 24. The atrial stimulation interval timer 25 is reset and time measurement is started (step S213). Then, the AVD setting unit 49 sets an AVD value (for example, 150 ms) for ensuring ventricular contraction in normal atrioventricular conduction stored in the first AVD storage unit 47 as a threshold value of the timeout time of the AVD measurement timer 28. (Step S214). Subsequently, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S212 is also supplied to the start terminal of the AVD measurement timer 28 via the OR circuit 24. The measurement of the measurement timer 28 starts (step S215), and the process proceeds to the process of FIG.

Next, a process (A) is demonstrated based on FIG.
As shown in FIG. 11, first, in the measurement AVD comparison unit 31, in response to the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S212, an atrial stimulation unit described later “N + 1” is added to the counter value N for counting the number of stimulations of the right atrium 11 by 3 and the counter value N is incremented (step S216). Then, it is determined whether or not the counter value has reached a predetermined number of times, that is, whether or not the counter value is equal to a predetermined value (N = 3 to 5) of the number of stimulations of the right atrium 11 by a predetermined atrial stimulation unit 3. (Step S217).

  When it is determined in determination step S217 that N is equal to a predetermined value (N = 3 to 5), the measurement AVD comparison unit 31 performs neural stimulation timing only once at the atrial stimulation timing in step S212. The unit 32 is allowed to stimulate the vagus nerve 13 via the nerve stimulating unit 14 (step S218), and prohibits the stimulation of the vagus nerve 13 at timings thereafter. The nerve stimulation timing unit 32 can also stimulate the vagus nerve 13 via the nerve stimulation unit 14 simultaneously with the atrial stimulation, or after waiting for a preset delay time from the atrial stimulation, via the nerve stimulation unit 14. It is also possible to stimulate the vagus nerve.

  Next, it is determined whether or not ventricular contraction is detected by the ventricular contraction detection unit 6 (step S219). If it is determined in this determination step S219 that the ventricular contraction is detected, the AVD measurement timer 28 sets the AVD measurement timer 28. The measurement is stopped, and the measurement AVD comparison unit 31 acquires the AVD measurement value at this time (step S220). And it transfers to the process of the process (B) shown by FIG.

  When it is determined in determination step S217 that N is not equal to a predetermined value (N = 3 to 5), it is subsequently determined whether or not ventricular contraction is detected from the ventricular contraction detection unit 6. (Step S221). If it is determined in step S221 that ventricular contraction has been detected, the AVD measurement timer 28 stops the AVD measurement, and the measurement AVD comparison unit 31 acquires the AVD measurement value at this time (step S222). Then, the process proceeds to the next step (B) shown in FIG.

  If it is determined in the determination step S221 that no ventricular contraction is detected from the ventricular contraction detection unit 6, it is subsequently determined whether or not the AVD measurement timer 28 has timed out (step S223). If it is determined in this determination step S223 that the AVD measurement timer 28 has timed out, an output signal is issued from the AVD comparison unit 30 to the ventricular stimulation unit 7, and the right ventricle 12 is stimulated (step S224). Then, the AVD measurement timer 28 is stopped (step S225), and the process proceeds to step (B) shown in FIG. If it is determined in the determination step S223 that the AVD measurement timer 28 has not timed out, the process returns to step S221 to wait for detection of the next ventricular contraction.

  Next, when it is determined in the determination step S219 that the ventricular contraction detector 6 does not detect ventricular contraction, it is determined whether or not the AVD measurement timer 28 has timed out (step S226). When it is determined in this determination step S226 that the AVD measurement timer 28 has timed out, a signal is sent from the AVD comparison unit 30 to the ventricular stimulation unit 7 to stimulate the right ventricle 12 (step S227). Then, the AVD measurement timer 28 is stopped (step S228), and the process proceeds to step (B) shown in FIG. If it is determined in the determination step S226 that the AVD measurement timer 28 has not timed out, the process returns to step S219 to wait for detection of the next ventricular contraction.

Next, the process (B) following the acquisition of the AVD measurement values in steps S220 and S222 and the stop of the AVD measurement timer 28 in steps S225 and S228 will be described with reference to FIG.
First, the measurement AVD comparison unit 31 determines whether or not the AVD measurement value has been acquired (step S229). When it is determined in this determination step S229 that the AVD measurement value can be acquired, that is, when the AVD measurement value can be acquired in step S200 or step S222, the measurement AVD comparison unit 31 calculates the average value of the acquired AVD measurement values. Are stored as AVD1 measurement values in the AVD1 recording unit 53 shown in FIG. 16 (step S230). On the other hand, when it is determined in the determination step S229 that the AVD measurement value could not be obtained, that is, when the ventricular contraction is not detected in step S219, the process proceeds to this determination step S229 via step S226, step S227, step S228. Alternatively, if the ventricular contraction is not detected in step S221 and the process proceeds to step S229 via steps S223, S224, and S225, the intensity of stimulation of the vagus nerve 13 based on the AVD measurement value cannot be controlled. Proceeding to (D) of FIG. 13, the control is switched to the normal control.

  From the reset / start process of the atrial stimulation interval timer 25 in step S209 described above to the process in which the average value of the AVD measurement values acquired in step S230 is set as the AVD1 measurement value is the AVD1 measurement value acquisition process.

  Next, it is determined whether or not the atrial stimulation interval timer 25 has timed out (step S231). If it is determined in this determination step S231 that the atrial stimulation interval timer 25 has timed out, a signal is sent from the atrial stimulation interval comparison unit 30 to the atrial stimulation unit 3 to stimulate the right atrium 11 (step S233). On the other hand, if it is determined in the determination step S231 that the atrial stimulation interval timer 25 has not timed out, it is subsequently determined whether or not atrial contraction is detected in the atrial contraction detection unit 2 (step S232). When it is determined in this determination step S232 that the atrial contraction is detected from the atrial contraction detection unit 2 (D), the heart rate cannot be kept constant by the atrial stimulation, and the AVD measurement value by the vagus nerve stimulation is not changed. Since it is difficult to accurately grasp the influence, the process proceeds to (D) of FIG. 13 and the control is switched to the normal control. If atrial contraction is not detected from the atrial contraction detection unit 2 in the determination step S232, the process returns to the determination in step S231.

  Next, after the atrial stimulation is performed in step S233, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in this atrial stimulation is transmitted via the OR circuit 24 to the atrial stimulation interval timer. 25, the atrial stimulation interval timer 25 is reset and time measurement is started (step S234). Then, in the AVD setting unit 49, an AVD value (for example, 300 ms) for securing the ventricular contraction in the posterior atrioventricular conduction stored in the second AVD storage unit 48 as the threshold value of the timeout time of the AVD measurement timer 28. Is set (step S235).

  Subsequently, the output of the atrial stimulation interval comparison unit 27 supplied to the atrial stimulation unit 3 in the atrial stimulation of step S233 is supplied to the start terminal of the AVD measurement timer 28 via the OR circuit 24, and the AVD measurement timer 28 Starts measuring time (step S236). Next, it is determined whether or not ventricular contraction is detected by the ventricular contraction detector 6 (step S237). If it is determined in this determination step S237 that ventricular contraction has been detected, the AVD measurement timer 28 stops the AVD measurement and acquires the AVD measurement value (step S238). Then, the measurement AVD comparison unit 31 sets the acquired AVD measurement value as the AVD2 measurement value (step S239) and stores it in the AVD2 recording unit 54 shown in FIG. Subsequently, the measurement AVD comparison unit 31 acquires an AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate from the comparison value table storage unit 50 (step S240), and thereafter Proceed to step (C) in FIG.

  If it is determined in step S237 that no ventricular contraction is detected, it is then determined whether the AVD measurement timer 28 has timed out (step S241). When it is determined in this determination step S241 that the AVD measurement timer 28 has timed out, a signal is sent from the AVD comparison unit 30 to the ventricular stimulation unit 3, and stimulation of the right ventricle 12 is performed (step S242). Then, the AVD measurement timer 28 is stopped (step S243). Then, since the AVD2 measurement value cannot be acquired and the intensity of the stimulation of the vagus nerve 13 based on the AVD measurement value cannot be controlled, the process proceeds to step (D) shown in FIG. 13 and switches to normal control. If the AVD measurement timer 28 has not timed out in the determination step S241, the process returns to step S237 and waits for detection of the next ventricular contraction.

  The process from the determination of the timeout of the atrial stimulation interval timer 25 in step S231 to the process of acquiring the AVD reference comparison value corresponding to the atrial stimulation rate in step S240 is the process of acquiring the AVD2 measurement value and the AVD reference comparison value.

Next, the process (C) after obtaining the AVD reference comparison value in step S240 of FIG. 12 will be described based on FIG.
First, in the measurement AVD comparison unit 31, the AVD 1 measurement value stored in the AVD 1 recording unit 53 and the AVD 2 measurement value stored in the AVD 2 recording unit 54 are supplied to the comparison value calculation unit 57. The comparison value calculator 57 outputs a relative ratio (AVD2 / AVD1) of the AVD2 measurement value to the AVD2 measurement value or a difference (AVD2-AVD1) between the AVD2 measurement value and the AVD1 measurement value. The output of the calculation unit 57 and the AVD reference comparison value (second predetermined value or third predetermined time) acquired in step S240 are compared in the comparison unit 51 (step S244).

  Then, as a result of this comparison, that is, the AVD1 measured value for the AVD2 measured value and the AVD reference comparison value (second predetermined value or third predetermined time) corresponding to the atrial stimulation rate acquired from the comparison value table storage unit 50 The comparison result of the relative ratio or the difference between the AVD2 measurement value and the AVD1 measurement value is supplied to the nerve stimulation signal parameter setting unit 33. The nerve stimulation signal parameter setting unit 33 determines a nerve stimulation signal parameter for the vagus nerve 13 based on the comparison result, and sets the parameter value in the nerve stimulation unit 14.

  For example, the relative ratio of the AVD1 measurement value to the AVD2 measurement value corresponding to the atrial stimulation rate or the difference between the AVD2 measurement value and the AVD1 measurement value is the optimal AVD reference comparison value (second predetermined value or third predetermined value). If it is less than (time), it is determined that the effect of the vagus nerve stimulation is small, and the nerve stimulation signal parameter setting unit 33 is currently set to the energy of the nerve stimulation signal, that is, parameters such as amplitude and pulse width. The value is increased by a predetermined amount from the value and set in the nerve stimulation unit 14 (step S245). Then, after the atrial stimulation frequency N is set to “0” (step S246), the process returns to the determination of the timeout of the atrial stimulation interval timer 25 shown in FIG. 10, and the AVD1 measurement value acquisition step, AVD2 measurement value and AVD comparison value The acquisition process and this process are repeated.

  In the determination step S244, the relative ratio of the AVD1 measurement value to the AVD2 measurement value or the difference between the AVD2 measurement value and the AVD1 measurement value is determined by the optimum AVD reference comparison value (second predetermined value or third predetermined value). Is greater than (time), the nerve stimulation signal parameter setting unit 33 determines that there is an effect of the desired vagus nerve stimulation by setting the current stimulation intensity, and ensures vagus nerve stimulation even if there is a change in the biological situation The parameter value of the nerve stimulation signal is updated with a value that is higher by a predetermined margin than the currently set value, and is set in the nerve stimulation unit 14 (step S247). Thereafter, the switching control unit 21 turns off the operation of the nerve stimulation signal parameter control unit 20, turns on the operation of the normal control unit 17, and returns to the normal control operation (step S248).

Thereby, the intensity of stimulation of the vagus nerve 13 can be optimally controlled based on the comparison between the AVD measurement value and the second predetermined value corresponding to the stimulation rate or the third predetermined time.
The relative determination or difference between the relative ratio or difference of the AVD measurement values and the AVD reference comparison value (second predetermined value or third predetermined time) in step S244 described above is based on the relative ratio or difference of the AVD measurement values. This is a process of changing the nerve stimulation signal parameter.

  As described above, the embodiment of the nerve stimulation intensity setting device of the present invention has been exemplified by the control of the nerve stimulation intensity in the heart treatment device based on the in-vivo implanted vagus nerve stimulation, but the embodiment of the present invention is not limited to this. Instead, the present invention can also be applied to an external measurement device for confirming a nerve stimulation threshold value and a nerve stimulation response characteristic at the time of surgery for implanting a heart treatment device based on vagus nerve stimulation in the body.

It is the block diagram which showed the structural example of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation which mounts the nerve stimulation intensity | strength setting apparatus of embodiment of this invention. It is a figure which shows the timing of vagus nerve stimulation and acquisition of an AVD measurement value. It is the block diagram which showed the structural example of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of other embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of other embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of other embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of other embodiment of this invention. It is a partial flowchart for demonstrating operation | movement of the heart treatment apparatus based on the vagus nerve stimulation carrying the nerve stimulation intensity | strength setting apparatus of other embodiment of this invention. It is a block diagram which shows the detailed structure of the measurement AVD comparison part 31 in "comparison with an AVD measurement value and 2nd predetermined time." 7 is a block diagram showing a detailed configuration of a measurement AVD comparison unit 31 in “Comparison of AVD2 Measurement Value / AVD1 Measurement Value and Second Predetermined Value”. FIG. It is a block diagram which shows the detailed structure of the measurement AVD comparison part 31 in "comparison with the 2nd predetermined value or 3rd predetermined time corresponding to an AVD measurement value and a stimulus rate".

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heart treatment apparatus, 2 ... Atrial contraction detection part, 3 ... Atrial stimulation part, 6 ... Ventricular contraction detection part, 7 ... Ventricular stimulation part, 13 ... Vagus nerve, 14 ... Nerve stimulation part, 20 ... Nerve stimulation signal parameter control 25: Atrial stimulation interval timer, 27 ... Atrial stimulation interval comparison unit, 28 ... AVD measurement timer, 30 ... AVD comparison unit, 31 ... Measurement AVD comparison unit, 32 ... Neural stimulation timing unit, 33 ... Neural stimulation signal parameter setting 41: Heart rate measurement unit, 42 ... Heart rate increment value calculation unit, 43 ... Heart rate fixed increment storage unit, 44 ... Selection unit, 45 ... Addition unit, 46 ... HR / PP conversion unit, 47 ... First AVD storage unit, 48 ... Second AVD storage unit, 49 ... AVD setting unit, 50 ... Comparison value table storage unit, 51 ... Comparison unit, 52 ... Predetermined value storage unit, 53 ... AVD1 recording unit, 54 ... AVD2 recording unit, 5 ... AVD2 / AVD1 calculation unit, 56 ... predetermined ratio storage unit, 57 ... comparison value calculation unit

Claims (31)

Atrioventricular conduction time measuring means for measuring the atrioventricular conduction time of the heart;
A comparison means for comparing the atrioventricular conduction time measurement means output with a second predetermined time ;
A nerve stimulation means for generating a nerve stimulation signal for stimulating the vagus nerve,
Control means connected to the nerve stimulation means and the atrioventricular conduction time measurement means,
The control means adjusts the parameter of the nerve stimulation signal in response to the output of the atrioventricular conduction time measuring means, and adjusts the parameter of the nerve stimulation signal in response to the output of the comparison means. A nerve stimulation intensity setting device.   An atrial stimulation means for stimulating the atrium at a predetermined rate; and a ventricular contraction detection means for detecting a contraction of the ventricle, wherein the atrioventricular conduction time measurement means is configured to detect the ventricular contraction from the atrial stimulation by the atrial stimulation means. 2. The nerve stimulation intensity setting device according to claim 1, which measures the time until the detection of ventricular contraction by. It further comprises a heart rate measuring means for measuring the heart rate,
The control unit is further connected to the atrial stimulation unit and the heart rate measurement unit, and sets the rate of the atrial stimulation unit based on an output of the heart rate measurement unit. Nerve stimulation intensity setting device.   The nerve stimulation intensity setting device according to claim 2 or 3, wherein the generation of the nerve stimulation signal is simultaneously with the stimulation of the atrium.   4. The nerve stimulation intensity setting device according to claim 2, wherein the generation of the nerve stimulation signal is performed after a predetermined delay time has elapsed from the stimulation of the atrium.   6. The nerve stimulation intensity setting device according to claim 5, wherein the predetermined delay time is a time until detection of the ventricular contraction.   6. The nerve stimulation intensity setting device according to claim 5, wherein the predetermined delay time is a time within atrioventricular conduction time.   4. The nerve stimulation intensity setting apparatus according to claim 3, wherein the control unit sets a value obtained by adding a predetermined value to the output of the heart rate measurement unit as the rate of the atrial stimulation unit.   The nerve stimulation intensity setting apparatus according to claim 8, wherein the predetermined value is a fixed heart rate value.   The nerve stimulation intensity setting device according to claim 8, wherein the predetermined value is a predetermined ratio of the measured heart rate.   And a ventricular stimulation means for generating a ventricular stimulation pulse for stimulating the ventricle when the detection of the ventricular contraction is not obtained even after a first predetermined time has elapsed since the generation of the atrial stimulation pulse. The nerve stimulation intensity | strength setting apparatus in any one of Claims 2-10 characterized by the above-mentioned.   The nerve stimulation intensity setting device according to claim 11, wherein the first predetermined time is extended in a cardiac cycle after the vagus nerve stimulation. The nerve stimulation intensity setting device according to claim 1 , wherein the second predetermined time is a function of a stimulation rate of the atrial stimulation means. 14. The parameter according to claim 1 or 13 , wherein the parameter is adjusted so that the stimulation energy of the nerve stimulation signal increases when the output of the atrioventricular conduction time measuring means is smaller than the second predetermined time. Nerve stimulation intensity setting device. 14. The parameter according to claim 1 , wherein the parameter is adjusted so that the stimulation energy of the nerve stimulation signal decreases when the output of the atrioventricular conduction time measuring means is larger than the second predetermined time. Nerve stimulation intensity setting device. Atrioventricular conduction time to make a comparison with the second predetermined time, according to claim 1 or 13 to 15, characterized in that it is AV conduction time in the neural stimulation signal the cardiac cycle later than the applied cardiac cycle The nerve stimulation intensity | strength setting apparatus in any one of. The nerve stimulation intensity setting device according to claim 1 , wherein the comparison means compares the atrioventricular conduction time measured in the first cardiac cycle with the atrioventricular conduction time measured in the second cardiac cycle. The first cardiac cycle is a cardiac cycle before or when the neural stimulation signal is applied, and the second cardiac cycle is a cardiac cycle after the neural stimulation signal is applied. The nerve stimulation intensity setting device according to claim 17 . It said second cardiac cycle is the cardiac cycle after the application of the neural stimulation signal, claim wherein said first cardiac cycle is the cardiac cycle later than said second cardiac cycle 17 The nerve stimulation intensity setting device described in 1. The comparison means calculates a difference (AVD2-AVDl) between the atrioventricular conduction time (AVD1) measured in the first cardiac cycle and the atrioventricular conduction time (AVD2) measured in the second cardiac cycle and a third predetermined time. The nerve stimulation intensity setting device according to any one of claims 17 to 19 , wherein comparison is performed. The nerve stimulation intensity setting device according to claim 20 , wherein the third predetermined time is a function of a stimulation rate of the atrial stimulation means. When the hidden (AVD2-AVDl) is smaller than the third predetermined time, according to claim 20 or 21, characterized in that stimulation energy of the neural stimulation signal to adjust the parameters so as to increase Neural stimulation intensity setting device. The said parameter is adjusted so that the stimulation energy of the said nerve stimulation signal may decrease when the said difference (AVD2-AVDl) is larger than the said 3rd predetermined time, The parameter | index of Claim 20 or 21 characterized by the above-mentioned. Neural stimulation intensity setting device. The comparison means calculates a ratio (AVD2 / AVDl) between the atrioventricular conduction time (AVD1) measured in the first cardiac cycle and the atrioventricular conduction time (AVD2) measured in the second cardiac cycle and a second predetermined value. The nerve stimulation intensity setting device according to any one of claims 17 to 19 , wherein comparison is performed. 25. The nerve stimulation intensity setting device according to claim 24 , wherein the second predetermined value is a function of a stimulation rate of the atrial stimulation means. 26. The parameter according to claim 24 , wherein when the ratio (AVD2 / AVDl) is smaller than the second predetermined value, the parameter is adjusted such that the stimulation energy of the nerve stimulation signal is increased. Neural stimulation intensity setting device. 26. The parameter according to claim 24 , wherein when the ratio (AVD2 / AVDl) is larger than the second predetermined value, the parameter is adjusted so that the stimulation energy of the nerve stimulation signal is decreased. Neural stimulation intensity setting device. The nerve stimulation intensity setting device according to any one of claims 1 to 27 , wherein the nerve stimulation signal is a single pulse signal. The nerve stimulation intensity setting device according to claim 1, wherein the nerve stimulation signal is a burst signal composed of a plurality of pulses. The nerve stimulation intensity setting device according to any one of claims 1 to 27 , wherein the adjustment of the parameter of the nerve stimulation signal includes at least one of a pulse amplitude and a pulse width. 31. A cardiac treatment device comprising the nerve stimulation intensity setting device according to claim 1 and having a housing that can be implanted into a living body.

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