JPH11319119A - Cardiac pacemaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stimulate the heart at a physiological stimulus rate even in a different kinetic form (such as walking on the level ground, running, going up the stairs or going down the stairs). SOLUTION: Numbers WC-X and WC-Z of steps are calculated from acceleration in advancing direction and acceleration in vertical direction by a metabolic request index calculating part 300 and when the kinetic form discriminated by a kinetic form discriminating part 200 is walking on the level ground, the number WC-X provided from the acceleration in advancing direction is selected by a metabolic request index selecting part 400 but when the kinetic form is running, going up the stairs or going down the stairs, the number WC-Z provided from the acceleration in the vertical direction is selected by the metabolic request index selecting part 400. At the same time, a cardiac stimulus rate function corresponding to the kinetic form discriminated by the kinetic form discriminating part 200 is selected by a cardiac stimulus rate function selecting part 600 and the cardiac stimulus rate is calculated by a cardiac stimulus rate calculating part 700 while using the number of steps with higher detection accuracy matched with each kinetic form as a metabolic request index so that the heart can be stimulated at the physiological cardiac stimulus rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a cardiac pacemaker, and more particularly to a cardiac pacemaker that controls a cardiac stimulation rate in accordance with a form of exercise.

[0002]

2. Description of the Related Art A cardiac pacemaker is used for a patient having a cardiac dysfunction or a stimulus conduction system disorder, and supplements the cardiac activity by performing electrical stimulation on the heart when the cardiac activity does not occur for a certain period of time. In the past, the rate at which the electrical stimulation was performed was fixed at a fixed rate, which sometimes limited the patient's movement. On the other hand, cardiac pacemakers have been developed in which a patient's metabolic demand is detected by a sensor and the heart stimulation rate is automatically adjusted. Most used as indicators.

[0003] In the exercise, a motion such as a foot kicking and landing on the ground accompanying a motion of a lower limb is detected as a body motion. The frequency of the detected motion (the number of steps during exercise) or the amount obtained by integrating the body vibration for a certain period of time has been used as an index indicating the metabolic rate.

As a sensor for detecting body vibration, a sensor for detecting an operation of a mechanical switch connected to the weight, which is generated by reciprocating in a space having a weight due to the body vibration, and a sensor for detecting a space in which a magnet exists. Detects changes in magnetic field caused by reciprocating motion, Detects contact by moving mercury enclosed in a container in which electrical contacts are arranged, Detects voltage changes due to deformation of piezoelectric element In general, a device that detects a change in resistance due to deformation of a piezoresistive element is used.

In the case of using the number of steps as body vibration, the longitudinal vibration of the patient is detected by a sensor, an output signal from the sensor is filtered and compared with a certain threshold value, and the number of times exceeding the threshold value is determined for a predetermined time. Some types of walking speed are obtained by counting, and the heart stimulation rate is adjusted accordingly. In the case of using the integration amount for a certain period of time as the body vibration, the sensor detects the vibration in either the front-rear direction or the vertical direction,
In some cases, the output signal of the sensor is filtered and then integrated for a certain period of time, and the heart stimulation rate is adjusted based on the integrated value.

[0006]

However, in a cardiac pacemaker using the number of steps as an index of the heart stimulation rate, if the walking speed is the same, walking such as walking on level ground, ascending stairs, descending stairs, ascending a slope, descending a slope, etc. Even if the state is different, it can not be distinguished,
All will be recognized as the same level of exercise. Therefore, for example, when comparing flat-walking and stair climbing, although stair climbing clearly has a larger metabolic rate, it is possible to detect a metabolic demand that matches the exercise state by judging only the number of steps. Because of this, the heart stimulation rate cannot be physiologically controlled.

In addition, since the number of steps detects one step in athletic movement when the acceleration exceeds a certain threshold value, in the step measurement by detecting the acceleration in the vertical direction, when walking slowly on flat ground, the vibration in the vertical direction is small and the detection accuracy is small. Is inferior. On the other hand, in the step count measurement by detecting the acceleration in the front-rear direction,
When the vibration in the traveling direction is small, such as when ascending or descending a stair, detection accuracy is poor.

Tables 1 and 2 show the results of the present inventors calculating the average walking speed from the acceleration in the traveling direction and the acceleration in the vertical direction below the collarbone during walking. Table 1 shows the results obtained by using the acceleration in the traveling direction to calculate the average walking speed when traveling on level ground, climbing stairs, and descending stairs. The threshold level used for the measurement was a value of 50% of the average value of the acceleration in the traveling direction per step when walking on level ground, averaged over the entire exercise time. Table 2 shows the result of calculating the average walking speed during walking on level ground using the vertical acceleration. The threshold level used for the measurement was a value of 50% of a value obtained by averaging the maximum value of the vertical acceleration per one step at the time of climbing the stairs over the entire exercise time.

[0009]

[Table 1]

[0010]

[Table 2]

[0011] In Table 1, it is impossible to measure (70, 90 steps / min down stairs) or misrecognize the average walking speed in a small direction (110 steps / min).
The average walking speed when descending stairs is 66.2 steps / min, the average walking speed when descending 130 steps / min is 111.8 steps / min, and the average walking speed when traveling on flat ground is 1303.8 steps / min. In some cases, the average walking speed when running on flat ground at 140 steps / min was erroneously recognized as 85.0 steps / min.). Since the threshold value is set so that the average walking speed is measured stably when walking on level ground, the acceleration in the traveling direction is lower when traveling on level ground, when climbing stairs, and when descending stairs compared to when walking on level ground. It is considered that the cause is that the acceleration does not exceed the set threshold value due to the small amplitude.

In Table 2, the case where the average walking speed is erroneously recognized in a small direction (the average walking speed of 90 steps / minute is erroneously recognized as 63.3 steps / minute, and the average walking speed of 110 steps / minute is erroneously recognized as 95.0 steps / minute) I found that there was. The threshold is set so that the average walking speed is measured stably when traveling on level ground, climbing stairs, and descending stairs. It is considered that the cause is that the amplitude of the vertical acceleration is small and the acceleration does not exceed the set threshold.

Further, even at the same walking speed, the body vibration in the front-rear direction when climbing up and down stairs is smaller than the body vibration during walking on flat ground, and the body vibration in the up-down direction is smaller than the body vibration during walking on flat ground. Big. Therefore, the integration amount of body vibration for a certain time is
In the front-rear direction, the amount of time when going up and down stairs is smaller than when walking on level ground,
In the vertical direction, when going up and down stairs compared to walking on flat ground,
In the vertical direction, descending stairs is larger than climbing stairs. Therefore, in a cardiac pacemaker that uses an integral amount for a certain period of time as an index of the cardiac stimulation rate, it is not possible to detect a request for a metabolic amount that matches the exercise state by judging only the integral amount for a certain period of body vibration. The stimulation rate cannot be controlled physiologically.

In a cardiac pacemaker that uses the number of steps within a certain period of time or the integral amount of body vibration for a certain period of time as an index, a sufficient increase in the heart stimulation rate cannot be obtained when the stairs rise, or an excessive heart rate decreases when the stairs descend. There have been reports of increased stimulation rates. (Markus M, Mic
hel S. Activity Controlled Cardiac Pacemakers Dur
ing Stairwalking. PACE1996, Vol.19, P1036-104
1) As one method for solving the above-mentioned problem, US Pat. No. 5,360,436 filed by Intermedics, Inc.
USP 5,447,524 states that the patient's lateral and vertical accelerations are measured, and that the algorithm that determines the heart stimulation rate between walking and cycling is determined based on the magnitude relationship between walking and cycling. Techniques are disclosed. However, the method of this patent is a technique applied to a special form of walking or biking, and the form of exercise is, for example, a difference in the form of walking (walking on a flat ground, walking on a slope, climbing a stair, descending a stair, etc.), walking. Can not be applied to determine the form of exercise when it is different from other exercises that differ from walking or running (bending and stretching of knees, lifting of luggage, etc.). It cannot be said that control is sufficient.

An object of the present invention is to provide a cardiac pacemaker which can stimulate the heart at a physiological stimulation rate even when the exercise mode is variously different such as walking on a flat ground, running, climbing a stair, descending a stair, and the like. I do.

[0016]

In order to solve the above-mentioned problems, a cardiac pacemaker according to the present invention comprises a motion detecting means for detecting a motion of a patient, and a motion for discriminating a motion form based on an output of the motion detecting means. Metamorphic request detecting means for detecting a physical quantity reflecting the metabolic demand of the patient,
A metabolic demand index calculating means for calculating a plurality of metabolic demand indexes from the output of the metabolic demand detecting means; and a plurality of metabolic demands calculated by the metabolic demand index calculating means according to the exercise mode determined by the exercise mode determining means. A metabolic demand index selecting means for selecting at least one metabolic demand index from the indexes; and a heart stimulus storing a plurality of cardiac stimulation rate functions corresponding to the plurality of metabolic demand indexes calculated by the metabolic demand index calculating means. Rate function storage means, a cardiac stimulation rate function selecting means for selecting the cardiac stimulation rate function in accordance with the exercise mode determined by the exercise mode determining means, and a metabolic demand index selected by the metabolic demand index selecting means. A heart stimulating rate calculated by the heart stimulating rate function selected by the heart stimulating rate function selecting means; Rate calculation means, heart stimulation rate control means for controlling the rate of heart stimulation based on the calculation result of the heart stimulation rate calculation means, and heart stimulation means for stimulating the heart at the heart stimulation rate It is characterized by.

Further, the cardiac pacemaker of the present invention has a motion detecting means for detecting the motion of the patient, a motion type discriminating means for discriminating the motion type based on the output of the motion detecting means, and reflects the metabolic demand of the patient. A plurality of metabolic request detecting means for detecting a physical quantity; and a metabolic request detecting selection for selecting at least one metabolic request detecting means from the plurality of metabolic request detecting means in accordance with the exercise mode determined by the exercise mode determining means. Means, a metabolic demand index calculating means for calculating a metabolic demand index from the output of the metabolic demand detecting means selected by the metabolic demand detection selecting means, and a plurality of metabolic demand indexes calculated by the metabolic demand index calculating means. A heart stimulus rate function storage unit in which a heart stimulus rate function is stored; and A heart stimulation rate function selecting means for selecting a splanchnic stimulation rate function; a metabolic demand index calculated by the metabolic demand index calculating means from an output of the metabolic demand detecting means selected by the metabolic demand detection selecting means; Heart stimulation rate calculation means for calculating a heart stimulation rate based on the heart stimulation rate function selected by the rate function selection means, and cardiac stimulation for controlling the rate of heart stimulation based on the calculation result of the heart stimulation rate calculation means It is characterized by comprising rate control means and heart stimulating means for stimulating the heart at the rate of the heart stimulus.

Further, the cardiac pacemaker of the present invention has a motion detecting means for detecting the motion of the patient, a motion type discriminating means for discriminating the motion type based on the output of the motion detecting means, and reflects the metabolic demand of the patient. A plurality of metabolic request detecting means for detecting a physical quantity; and a metabolic request detecting selection for selecting at least one metabolic request detecting means from the plurality of metabolic request detecting means in accordance with the exercise mode determined by the exercise mode determining means. Means, a metabolic demand index calculating means for calculating a plurality of metabolic demand indices from the output of the metabolic demand detecting means selected by the metabolic demand detection selecting means, and according to the exercise mode determined by the exercise mode determining means, Metabolic demand index selecting means for selecting at least one metabolic demand index from a plurality of metabolic demand indexes calculated by the metabolic demand index calculating means The cardiac stimulation rate function storage means in which a plurality of cardiac stimulation rate function is stored for metabolic demand indicator calculated by the metabolic demand index calculating means, depending on the motion form which is determined by the motion form determining means,
Cardiac stimulation rate function selecting means for selecting the cardiac stimulation rate function; and a plurality of metabolic demand indices calculated by the metabolic demand index calculating means using the output of the metabolic demand detecting means selected by the metabolic demand detecting / selecting means. A heart stimulation rate calculating means for calculating a heart stimulation rate according to the metabolic demand index selected by the metabolic demand index selecting means and the heart stimulation rate function selected by the heart stimulation rate function selecting means; A heart stimulus rate control means for controlling a rate of a heart stimulus based on a calculation result of the rate calculation means, and a heart stimulus means for stimulating a heart at the heart stimulus rate.

In the cardiac pacemaker, the exercise form discriminating means discriminates an exercise form based on the detection result of the exercise detecting means, and the exercise form discriminated by the exercise form discriminating means includes walking on a flat ground, running, and climbing a stair. , The stairs descending, the motion detecting means comprises an acceleration sensor capable of independently detecting orthogonal two-axis or three-axis acceleration, and the metabolic demand index is calculated from the acceleration in two or more different directions of the acceleration sensor, respectively. For example, the number of steps or the average walking speed within a set time is desirable. In addition, it is desirable to use the acceleration in the moving direction of the patient's movement and the acceleration in the vertical direction as the acceleration in two or more different directions.

In the above pacemaker, the metabolic demand index calculating means calculates an average walking speed from the acceleration in the traveling direction and the vertical acceleration, and if the exercise mode determined by the exercise mode determining means is level walking, the metabolic demand index selecting means is used. Select the average walking speed obtained from the acceleration in the traveling direction, and if the exercise form is running, stair climb, stair descend,
By selecting the average walking speed obtained from the vertical acceleration by the metabolic demand index selecting means, calculating the heart stimulation rate using the average walking speed with high detection accuracy suitable for each exercise form as the metabolic demand index Stimulates the heart at a physiological stimulation rate. Note that the processing of the metabolic demand index calculating means is not necessarily limited to the calculation, and the output itself of the metabolic demand detecting means may be output as a metabolic demand index, or the output of the metabolic demand detecting means may be filtered or biased. The case of outputting as a metabolic demand index with only a few operations such as setting and gain setting is also included.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a cardiac pacemaker according to the present invention.
The “metabolism demand index” used in this specification is an index that is correlated with the metabolism required by the exercise of the patient, and the metabolism demand of the patient is calculated from the index by a calculation formula (function, algorithm). Can be estimated. "

In the present embodiment, the present invention will be described using an average walking speed as an example of a metabolic demand index of a cardiac stimulation rate. For example, when a body movement sensor is used, the amount of body movement ( An output obtained from the sensor and the sensing circuit, or a signal obtained by filtering the output,
Detection, conversion to absolute value or squaring, and use of values obtained by integration processing, averaging processing or addition processing), body motion intensity (output obtained from sensors and sensing circuits, or the maximum of signals obtained by filtering the output) Use amplitude value etc.)
Can be used as a metabolic demand index. In addition, other metabolic demand indicators are measured by the impedance method, such as respiratory rate, tidal volume, minute ventilation, tidal volume, pulse volume, time before ejection, and temperature sensor. Central venous blood temperature, venous oxygen saturation or arterial oxygen saturation measured by oxygen saturation sensor, nerve impulse frequency measured by nerve sensor, blood catecholamine measured by hormone sensor, electromyogram EMG pulse amplitude and EMG pulse frequency to be measured, blood lactate amount measured by a lactate sensor, blood oxygen partial pressure and blood carbon gas partial pressure measured by a blood gas sensor, blood pressure measured by a blood pressure sensor Values and blood pressure change rates, QT intervals measured by an electrocardiogram, blood pH measured by a pH sensor, and the like can also be used.

<First Embodiment> FIG. 1A shows an example of a cardiac pacemaker according to a first embodiment, in which a three-axis acceleration sensor is used in common for motion detecting means and metabolic demand detecting means, and two metabolic demand sensors are used. FIG. 10 is a block diagram showing a case where an index is calculated and one metabolic demand index is selected according to the exercise mode.

The exercise detecting section and the metabolic demand detecting section 100
A three-axis acceleration sensor 1a and an acceleration sensing circuit 2a for amplifying the output of the sensor and outputting it as a digital signal
It is composed of The exercise form discriminating unit 200 includes a DSP
(Digital Signal Processor) 3a and a register REG3 (6a) for temporarily storing the result of exercise form discrimination. In the present embodiment, the metabolic request index uses two of an average walking speed calculated from the acceleration in the front-rear direction and an average walking speed calculated from the acceleration in the vertical direction. Registers REG1 (4a), RE for temporarily storing the DSP 3a and the metabolic demand index calculation result
G2 (5a). Metabolic demand index selection section 40
0 comprises a selector SEL1 (11a) for switching the output of REG1 and REG2 in accordance with the output of REG3.
If the exercise mode EXER is level walking, select the average walking speed calculated from the acceleration in the front-rear direction. If the exercise mode EXER is running, climbing stairs, descending the stairs, select the average walking speed. Select a walking speed.

Further, in the present embodiment, fwalk (during running on flat ground), frun (during running), fupst
(When the stairs rise) and fdownst (when the stairs fall) are used, and the heart stimulation rate function storage unit 500 stores the REG4 (7
a), REG5 (8a), REG6 (9a), and REG7 (10a). The heart stimulus rate function selection unit 600 selects a selector SEL2 (12) for switching the outputs of REG4 to REG7 according to the exercise mode EXER of the register REG3.
a).

The heart stimulus rate calculating section 700 has an arithmetic circuit 1
3a, and calculates the heart stimulation rate using the outputs of SEL1 and SEL2. REG4, REG5, REG6, REG7 have coefficients, constants,
Contains information such as operators. From the information selected based on the exercise form information EXER and the average walking speed, the above-described arithmetic circuit 13a executes the calculation of the cardiac stimulation rate by the corresponding cardiac stimulation rate function. If there are common terms in the form, coefficient, and constant of the four cardiac stimulation rate functions, they can be included in the arithmetic circuit. The cardiac stimulation rate control unit 800 includes a pacing control circuit 14a, and performs appropriate stimulation based on a condition determination including the self-heart rate sensing output from the electrocardiographic signal sensing circuit 16a in the cardiac stimulation rate calculated by the arithmetic circuit 13a. The rate pacing trigger output is output to the heart stimulating unit 900. The heart stimulating unit 900 includes a driver circuit 15a that generates a pacing pulse having a voltage amplitude necessary for pulsation of the heart in synchronization with a trigger output from the pacing control circuit 14a. An unpaced pacing lead leads into the heart chamber and stimulates and beats the patient's heart.

An example of the heart stimulation rate function f (WC) when the metabolic demand index is WC is shown below.

Rt = R_basic (WC <WC_basic), Rt = fwalk = Awalk × (WC−WC_basic) + Bwalk + R_basic frun = Arun × (WC−WC_basic) + Brun + R_basic fupst = Aupst × (WC−WC_basic) + Bupst + R_basic fdownst = Adownst × (WC−WC_basic) + Bdownst + R_basic (WC ≧ WC_basic) (1 equation) where WC_basic is a basic index, Awalk (when walking on level ground), A
run (when running), Aupst (when stairs are up), Adownst (when stairs are down) are metabolic demand indices for each exercise form
Bwalk, a linear coefficient that connects WC and target rate Rt
(When walking on level ground), Brun (when running), Bupst (when climbing stairs), Bdownst (when descending stairs) are the target rate Rt and the basic rate when the metabolic demand index WC in each exercise form is equal to the basic index WC_basic This is the difference (intercept) of R_basic. The basic index is a metabolic demand index value at which the heart rate does not increase if the metabolic demand index WC detected even after exercise is equal to or less than the basic index.

The heart stimulation rate calculation function may be a function represented by another equation other than the one equation, or if one target rate corresponds to one value of the metabolic demand index WC, the heart stimulation rate is calculated. The calculation function does not have to be a function represented by a mathematical expression.

In the DSP 3a, discrimination of the movement form of walking on a flat ground, running, climbing stairs, climbing stairs, and calculating the average walking speed are performed by Cardiopacing Research Laboratory Co., Ltd. Body Motion Detection Method and Apparatus Thereof ”(Japanese Patent Application No. 9-100306). In the above "body movement detection method and device", the acceleration is detected independently in two or three directions attached to or implanted in the human body and orthogonal to the ground. Calculate the intensity and the intensity of the vertical acceleration that is almost perpendicular to the ground, and calculate the exercise form (level walking,
A device for discriminating between traveling, stair climbing, and stair descending has been proposed. The outline will be described below with reference to FIG. 5 and FIGS. 6A and 6B.

(Example of Configuration of DSP 3a) FIG. 5 is a diagram showing an example of the configuration of the exercise mode discriminating unit 200 and the metabolic demand index calculating unit 300 including the DSP of the present embodiment.

The apparatus shown in FIG. 5 has an acceleration sensing section (1) having a plurality of acceleration sensors, and coordinate conversion for calculating a traveling direction acceleration and a vertical acceleration from acceleration information output from the acceleration sensing section (1). Part (49),
An acceleration intensity calculation unit (2) for calculating the intensity of the traveling direction acceleration and the intensity of the vertical direction acceleration from the traveling direction acceleration and the vertical direction acceleration output from the coordinate conversion unit (49); An average walking speed measuring unit (3) for measuring an average walking speed based on the output traveling direction acceleration and vertical acceleration, and an exercise mode for determining the exercise mode based on the acceleration intensity output from the acceleration intensity calculating unit (2). A discrimination unit (46), an external vibration identification unit (47) for identifying a body motion caused by the external vibration caused by the motion from the acceleration intensity output from the acceleration intensity calculation unit (2), and an acceleration sensing unit ( 1) process the acceleration waveform output from
An angle correction coefficient calculation unit (48) for calculating an angle correction coefficient. In particular, an operation algorithm is illustrated in the coordinate conversion unit (49), the acceleration intensity calculation unit (2), and the average walking speed measurement unit (3).

An acceleration sensing unit (1) including an acceleration sensor measures three-axis acceleration, and inputs a value including a DC component to a coordinate conversion unit (49). The acceleration sensor is fixed inside the pacemaker, and the sensor X-axis at this time is set so as to be perpendicular to the plane of the pacemaker case, that is, to face the front-back direction of the body when implanted. The input range is arbitrary, but in this embodiment, the X axis is ± 1.5
The G, Y, and Z axes were ± 3G. According to the analysis of the data by the inventor, the ratio of the absolute value of the amplitude of the AC component between the acceleration in the traveling direction and the acceleration in the vertical direction was approximately 1: 2 when walking on level ground, climbing stairs, and descending. Therefore, the X-axis range is set to １ ／ of the Y- and Z-axis ranges to improve the accuracy of the X-axis acceleration.

Next, a band pass filter (4, 5, 6)
Then, the gravitational acceleration and the high frequency vibration are removed. The band of the band-pass filter is arbitrary as long as the purpose of removing gravitational acceleration and high-frequency vibration is achieved. However, according to the analysis of the data by the inventor, it is known that the frequency of the body motion due to the movement appears as twice the reciprocal of the walking and running cycle, and that the frequency band of 6 Hz or more at the time of fast running.
Therefore, the high-frequency cutoff frequency was set to 10 Hz so as not to remove the high-frequency component of the body motion due to the movement. The low frequency cutoff frequency is to eliminate gravitational acceleration and
Considering not removing body movements of walking that is as slow as about 0 / min.
5 Hz. The accelerations in the X, Y, and Z axes passing through the band-pass filters (4, 5, 6) are assumed to be Ax, Ay, Az.

As in the case of body motion detection used in a pedometer, when the sensor can be attached to the body surface, an acceleration sensing unit capable of measuring acceleration in two orthogonal directions is used.
By setting the axis to the front-back direction of the human body parallel to the horizontal plane or to the direction about 10 degrees upward from the front-back direction of the human body parallel to the horizontal plane and the direction substantially parallel to the direction of gravity, the acceleration in the traveling direction (XACT) And the magnitude of vertical acceleration (ZACT) can be measured. However, when implanted in a human body as in the case of body motion detection used in a pacemaker, the direction of acceleration detection does not coincide with the traveling direction and the vertical direction, so a coordinate conversion function for correcting the deviation is required.

The calculation of the acceleration in the traveling direction and the acceleration in the vertical direction in the coordinate conversion unit (49) is performed by the following equations (1) and (2).
As shown in the figure, the angle correction coefficient
Kx1 (7), Ky1 (8), Kz1 (9), Kx2 (10), Ky2 (1
1), Kz2 (12) are multiplied by multipliers (13, 14, 15, 16, 17, 18) to calculate the respective traveling direction components and vertical components of the three-axis acceleration, and adder ( This is performed by adding the components of the three axes in (19, 20).

Traveling direction acceleration: AxX = Kx1 × Ax + Ky1 × Ay + Kz1 × Az (Expression 2) Vertical acceleration: AzZ = Kx2 × Ax + Ky2 × Ay + Kz2 × Az (Expression 3) Angle correction coefficient The calculation of Kx1 to Kz2 is performed by an angle correction coefficient calculation unit (48). First, the elevation angle and the deviation angle of the pacemaker required for calculating Kx1 to Kz2 are determined at the time of the periodic examination by X, Y,
The acceleration signal before performing each filtering process of the Z axis is read out from the pacemaker by telemetry, and its DC component is measured externally, or X,
By measuring the DC component of the acceleration signal before performing the respective filtering processes on the Y and Z axes, the following equations (4) and (5) are obtained.
Equation (6) and Equation (6).

Here, the elevation angle and the deviation angle of the pacemaker are used, and Kx1 to Kz2 are determined at the time of a regular medical checkup or at predetermined intervals by the following equations (7), (8), (9), and (10). ),
It is calculated as shown in (Equation 11) and (Equation 12). At this time, the elevation angle φ of the pacemaker is a measured value or a value smaller by about 10 degrees than the measured value, so that the acceleration in the traveling direction is 10 degrees from the longitudinal direction of the human body parallel to the horizontal plane or the longitudinal direction of the human body parallel to the horizontal plane. The direction is forward and backward.

Elevation angle of pacemaker: φ = sin-1 ｛DC component of sensor X-axis acceleration / gravity acceleration｝ (4) Pacemaker deviation angle: θ = sin-1 ｛DC component of sensor Y-axis acceleration / (gravity Acceleration degree x cos φ)｝ (Equation 5) θ = cos-1 直流 DC component of sensor Z-axis acceleration / (gravity acceleration x cos φ)｝ (Equation 6) Angle correction coefficient: Kx1 = K / 2 x cos φ ... (7) Ky1 = -K x sin φ x sin θ ... (8) Kz1 = -K x sin φ x cos θ ... (9) Kx2 = K / 4 x sin φ ... (10) Ky2 = K / 2 × cos φ × sin θ ... (Equation 11) Kz2 = K / 2 × cos φ × cos θ ... (Equation 12) Considering the difference between the input dynamic range of the X axis and Y, Z axes of the acceleration sensing part And the angle correction coefficients Kx1 and Kx2 are 1
/ 2. Also, when the acceleration intensity is calculated between the traveling direction acceleration and the vertical direction acceleration, the angle correction coefficients Kx2, Ky2, and Kz2 are calculated as 1/1, taking into account the property that the acceleration intensity is greater in the vertical direction than in the traveling direction even if the amplitude is the same. Two. Therefore, the angle correction coefficient Kx2 is 1/4. A coefficient K in the angle correction coefficients Kx1 to Kz2 is an arbitrary coefficient for adjusting the maximum value of the acceleration intensity, and is adjusted according to the physique and activity status of the patient. Next, the traveling direction acceleration and the vertical direction acceleration are squared (or converted to an absolute value or detected).
Then, an average value (or an integrated value or an added value) of the processing output for a predetermined time is calculated, and the calculated value is set as the acceleration intensity.
In the present embodiment, the traveling direction acceleration and the vertical direction acceleration are squared by the multipliers (21, 22), and the low-pass filters (23,
24) Calculate the average value for the past 4 seconds. Furthermore, clipping is performed by the clipper (25, 26) to prevent overflow when processing a large acceleration during traveling or the like, and calculate the traveling direction acceleration intensity (XACT) and the vertical direction acceleration intensity (ZACT).

Next, the algorithm of the average walking speed measuring section (3) will be described. The average walking speed is measured independently for the traveling direction acceleration and the vertical direction acceleration. In the vertical acceleration, the vertical acceleration output from the adder (20) is added to the vertical acceleration so that the average walking speed can be measured from either the upward acceleration component or the downward acceleration component.
Kneg (27), the value is 1 or -1, multiplied by the multiplier (28),
The sign can be reversed.

First, the acceleration signals in the traveling direction and the vertical direction and threshold values sthX and sthZ (29, 30) are compared with comparators (31, 32).
And a signal is generated when the acceleration signal becomes larger than the threshold value. The pulse generator (33, 34) generates a non-trigger pulse of 300ms width in synchronization with the comparator signal. The non-trigger function does not generate a pulse even if the comparator signal comes again within 300 ms.
Two peaks were added to address the gait.
The means for generating a non-trigger pulse having a width of 300 ms is provided with a means for measuring the elapsed time after detecting the comparator signal so that the comparator signal is not detected even if the comparator signal is detected again within 300 ms. It can be replaced with simple software means.

Next, the number of pulses that appear every predetermined time (four seconds in the present embodiment) is counted by a counter (35, 36), and is set as XWS, ZWS (the number of steps per fixed time). Also, the time from the rise of the first pulse to the rise of the next pulse in the predetermined time is counted by the counters (37, 38), and added by the adders (39, 40).
1, 42), further counts the time until the next pulse and adds it to the register (41, 42). Finally, the time to the last pulse within 4 seconds is added to the register (41). ,
Set the value of (42) as XWTM, ZWTM (walking time) and register (4
1, 42), and reset the counters (37, 38). Finally, the dividers (43, 44) calculate {XWS (steps per fixed time) -1} / XWTM (walking time) and {ZWS (steps per fixed time) -1} / ZWTM (walking time). , The average walking speed per unit time.

Table 3 shows XACT when walking on level ground, traveling on level ground, ascending stairs and descending stairs, with varying walking speeds collected by the inventor.
Shows the average, maximum and minimum values of ZACT and ZACT / XACT.

[0044]

[Table 3]

FIG. 6A and FIG.
B. Based on FIGS. 6A and 6B, the exercise mode determination unit (4
In 6), the exercise form is determined.

<Modification of First Embodiment> FIG. 1A shows an example in which each component is constituted by hardware. However, as another example of this embodiment, an example using a microprocessor is shown in FIG. 1B. Shown in

In the present embodiment, the processing in the metabolic demand index selecting section 400, the cardiac stimulation rate function storing section 500, the cardiac stimulation rate function selecting section 600, and the cardiac stimulation rate calculating section 700 in the configuration of FIG. CPU 101
0, a ROM 1020, and a RAM 1030. Also in the present embodiment, the motion detection unit 100, the motion mode discrimination unit 200, the metabolic demand index calculation unit 300, the heart stimulation rate control unit 800, and the heart stimulation unit 900 are configured by hardware as in FIG. 1A.

FIG. 1C and FIG. 1D show the microprocessor 1
000 shows the processing algorithm. This will be described in detail below.

At step S100, the exercise form EXE is stored in the RAM 1020 of the microprocessor 1000 from REG3.
R, WC_X (average walking speed calculated from acceleration in the traveling direction) from REG1, and WC_Z (average walking speed calculated from vertical acceleration) from REG2, are read from ROM 1010 or R
The AM 1020 includes a basic rate (R_basic), a maximum rate (Rmax), a stimulus rate (Rpace), and a rising fluctuation rate (dRu).
p), descent rate (dRdown), heart rate function fwa
lk (when walking on level ground), frun (when running), fupst (when stairs are up), and fdownst (when stairs are down) are prepared. Note that the real-time stimulation rate (Rpace) is stored in the RAM 1020, but the standard stimulation rate and other parameters and functions are represented by R
The data may be stored in the OM 1010 as fixed data, or may be rewritably loaded in the RAM 1020.

If the exercise mode EXER is a flat-ground walk WALK, the process proceeds from step S110 to step S111. In steps S111 and S112, the metabolic demand index WC_X (average walking speed calculated from the acceleration in the traveling direction) and the heart stimulation rate function fw
alk is selected, and a target rate Rt is calculated by a cardiac stimulation rate function fwalk using WC_X as an index in step S150. If the exercise mode EXER is run RUN, step S
The process proceeds from S120 to S121, and steps S121 and S1 are performed.
In step 22, a metabolic demand index WC_Z (average walking speed calculated from vertical acceleration) and a cardiac stimulation rate function frun are selected, and in step S150, a cardiac stimulation rate function using WC_Z as an index.
Calculate the target rate Rt with frun. If the exercise form EXER is the stair climbing UPST, steps S130 to S1
Proceeding to 31, the metabolic demand index WC_Z (the average walking speed calculated from the vertical acceleration) in steps S131 and S132
And the heart stimulation rate function fupst are selected, and step S15
At 0, the target rate Rt is calculated by the heart stimulation rate function fupst using WC_Z as an index. Exercise form EXER goes down stairs DO
If it is WNST, the process proceeds from step S140 to S141, and in steps S141 and S142, the metabolic demand index WC_Z
(Average walking speed calculated from vertical acceleration) and heart stimulation rate function fdownst, and WC_
The target rate Rt is calculated by the heart stimulation rate function fdownst using Z as an index.

As described above, at least one metabolic demand index is selected from two or more metabolic demand indexes for each exercise mode,
The feature of the present embodiment is that the target rate is calculated using the metabolic demand index as an index, thereby enabling physiological heart rate control. If the obtained target rate is larger than the maximum rate Rmax and smaller than the basic rate R_basic, step S170
In S173, clipping is performed at the maximum rate Rmax and the basic rate R_basic, respectively.

In calculating the target rate,
The reference table of the target rate is recorded in the memory in advance, and the address where the value of the target rate corresponding to the metabolic demand index WC is recorded is searched based on the metabolic demand index WC, and recorded at the address. It is also possible to derive the value of the calculated target rate. Parameters such as coefficients and reference tables relating to the heart stimulation rate function can be externally changed by a programmer.

From the target rate Rt to the heart stimulation rate Rp
As an example of processing for calculating ace, steps S180 to S180
S186 is executed. If the current heart stimulation rate Rpace is equal to or higher than the target rate Rt, the heart stimulation rate Rpace subtracts the falling fluctuation rate dRdown (S184); otherwise, the heart stimulation rate Rpace adds the rising fluctuation rate dRup (S181). Heart stimulation rate is the maximum rate Rmax
If it is greater than and less than the basic rate R_basic, the maximum rate Rmax and the basic rate R_ba respectively.
clip with sic (S182, S183, S185,
S186). In step S190, the real-time cardiac stimulation rate (Rpace) is output to the cardiac stimulation rate control unit 800.

In the present embodiment, the metabolic demand index selecting section 400, the cardiac stimulation rate function storage section 500, the cardiac stimulation rate function selecting section 600, the cardiac stimulation rate calculating section 700
Was performed by a software method using a microprocessor, but the processing in the exercise form discriminating unit 200 and the metabolic demand index calculating unit 300 may be performed by a software method using a microprocessor. What to implement in hardware and what to implement in software, whether to use a single microprocessor, or to provide multiple microprocessors in parallel or in series, consider processing speed, reliability, and miniaturization. Is determined.

FIG. 7 shows an example of the configuration of a cardiac pacemaker in which the entire control unit is realized by software. Many parts of FIG. 7 can be realized by integrated IC chips.

Reference numeral 81 denotes a CPU for controlling the operation of the entire pacemaker, and reference numeral 82 denotes an RO for storing the processing procedure of the CPU 81.
M, and the processing procedure is the exercise form discrimination program 8
2a, a metabolic demand index calculation program 82b, and a pacemaker heart stimulation rate calculation program 82c are stored. Reference numeral 83 denotes a RAM for auxiliary storage, which is the exercise mode information 8 determined by executing the exercise mode determination program 82a.
The step number 83a calculated by the metabolic demand index calculation program 82b and constants such as angle correction coefficients are stored and used for drive control of the pacemaker. Reference numeral 84 denotes an input interface for inputting various external information, and interfaces with information from a pulse detection unit 84a and an acceleration detection unit 84b for detecting, for example, a user's heartbeat and the like. 8
Reference numeral 5 denotes an output interface for outputting various kinds of information to the outside, and is connected to, for example, a pulse generator 85a for outputting a drive pulse to the heart. 86 is a power supply.

<Second Embodiment> FIG. 2A shows a cardiac pacemaker according to a second embodiment, in which the exercise detector is used as one of the metabolic demand detectors.
FIG. 4 is a block diagram showing a case where one metabolic request detecting unit is selected from two metabolic request detecting units.

In the present embodiment, the motion detecting section 100
It includes a first sensor 1c and a first sensing circuit 2c that amplifies the output of the first sensor 1c and outputs the amplified signal as a digital signal. The exercise detecting unit 100 is commonly used as one of the metabolic demand detecting units. The metabolic demand detecting unit 101 includes a second sensor 10c and a second sensing circuit 11c that amplifies the output of the second sensor 10c and outputs the amplified signal as a digital signal. Here, the first sensor 1c and the first sensing circuit 2
For c, a sensor and a sensing circuit capable of discriminating the exercise form from the detected information are used. Also, depending on the detected exercise mode, a metabolic demand index is calculated from information detected by the first sensor 1c and the first sensing circuit 2c,
It is determined whether a metabolic demand index is calculated from information detected by the second sensor 10c and the second sensing circuit 11c, and a sensor and a sensing circuit suitable for each exercise form are selected, so that cardiac stimulation having a high correlation with metabolic demand is performed. Becomes possible.

For example, assuming that a body motion sensor such as a three-axis acceleration sensor is used as the first sensor 1c, FIG.
As shown in (2), when detecting an external vibration (including when no body movement is detected) while riding on a vehicle, a metabolic demand index for determining a heart stimulation rate is obtained from the outputs of the body movement sensor and the sensing circuit. Cannot be calculated. Therefore, when the motion mode is the external vibration (including the non-detection of the body motion), the second sensor 10c and the second sensing circuit 1 that are different from the body motion sensor
It is desired to calculate the metabolic demand index using the information obtained from 1c. Some examples of those sensors and metabolic demand indicators are listed at the beginning of the embodiment. That is,
The combination of the first sensor 1c and the second sensor 10c is
It is desirable to select those whose detection is complementary. still,
In this example, two types of different sensors are used. However, if an increase in the size can be avoided, the reliability can be further improved by using more types of sensors.
In this case, the determination of the exercise mode may be performed based on the detection of a plurality of types of sensors.

Hereinafter, a case where a three-axis acceleration sensor is used as the first sensor 1c will be described as an example. Exercise form discriminator 200
Is composed of a DSP 11 and a register REG3 (6a) for temporarily storing a result of exercise mode discrimination. Motion detection selector 1
Reference numeral 100 denotes a selector SEL11 (12c) for switching the outputs of the acceleration sensing circuit 2c and the second sensing circuit 11c according to the exercise mode EXER. The metabolic demand index calculating unit 300 stores the DSP 12 (13c) and the metabolic demand index calculation result in the register REG12 (14).
c). In the present embodiment, fwalk (during walking on flat ground), frun (during running), fup
st (when ascending stairs), fdownst (when descending stairs), fnoise
(External vibration detection and body motion non-detection) are used, and the heart stimulation rate function storage unit 500 stores REG4, REG5,
REG6, REG7, REG8 are comprised of five registers. The heart stimulus rate function selection unit 600 includes a motion form EXER
The selector SEL2 switches the outputs of the REG4 to REG8 in accordance with the conditions. The heart stimulus rate calculation unit 700 includes an arithmetic circuit 13
a, the heart stimulation rate is calculated using the outputs of REG12 and SEL2. The cardiac stimulation rate control section 800 is constituted by a pacing control circuit 14a, and the cardiac stimulation rate calculated by the arithmetic circuit 13a is added to the electrocardiogram signal sensing circuit 1
A pacing trigger output having an appropriate stimulus rate is output to the heart stimulating unit 900 based on the condition determination including the self-heart-rate sensing output from 6a. The heart stimulating unit 900 is composed of a driver circuit 15a, and the output of the driver circuit 15a is guided into the heart chamber by a pacing lead (not shown) through a connector unit, and stimulates and beats the patient's heart.

Note that the DSP 11 in the present embodiment is
For example, the DSP includes the functions of the coordinate conversion unit (49), the acceleration intensity calculation unit (2), and the exercise mode determination unit (46) in FIG.
12 includes a coordinate conversion unit (49) and a step number measurement unit (3). Note that if the DSP of FIG. 5 is a one-chip IC, the DSP 11 and the DSP 12 may use a common chip.

<Modification of Second Embodiment> In FIG. 2A, an example in which each component is configured by hardware has been described, but as a modification of the second embodiment, an example using a microprocessor is illustrated. 2B.

In this embodiment, the motion detection and selection unit 1100, the heart stimulation rate function storage unit 500, the heart stimulation rate function selection unit 600, and the heart stimulation rate calculation unit 700
The processing in the CPU 1210, the ROM 1220, and the R
This is performed by a software method using a microprocessor 1200 composed of the AM 1230. Also in the present embodiment, the exercise detecting unit 100, the metabolic request detecting unit 101, the exercise form determining unit 200, the metabolic request index calculating unit 300, the cardiac stimulation rate control unit 800, and the cardiac stimulating unit 900 are hardware similar to FIG. 2A. It consists of. However, in the metabolic demand index calculating section 300 of the present embodiment, the DSP
21 and 22 are provided, and the calculation of the metabolic demand index by the detection of the first sensor 1c and the calculation of the metabolic demand index by the detection of the second sensor 10c are executed in parallel.

FIG. 2C and FIG. 2D show the microprocessor 1
2 shows an algorithm of processing in 200. This will be described in detail below.

At step S200, the exercise form EXE is stored in the RAM 1220 of the microprocessor 1200 from REG3.
R, REG21 to X_S1 (metabolism demand index by the first sensor),
X_S2 (metabolism demand index by the second sensor) is read from REG22, and stored in ROM 1210 or RAM 1220,
Basic rate (R_basic), maximum rate (Rmax), cardiac stimulation rate (Rpace), rising fluctuation rate (dRup), falling fluctuation rate (dRdown), heart stimulation rate function fwalk (during parallel walking), frun (during running), fupst (when stairs rise), fdownst
(When stairs descend) and fnoise (when extraneous vibration is detected and body motion is not detected) are prepared. In addition, the real-time heart stimulation rate (Rpac
e) is stored in the RAM 1220, but the standard cardiac stimulation rate and other parameters and functions may be stored in the ROM 1210 as fixed data,
It may be rewritably loaded to 0.

If the exercise mode EXER is walking on level ground, the flow advances from step S210 to step S211. In steps S211 and S212, the metabolic request index X_Sn (the metabolic request by the sensor n (n = 1 or 2) which was in level ground walking) is used. Index) and the heart stimulation rate function fwalk are selected, and in step S250, X_S
The target rate Rt is calculated using the heart stimulation rate function fwalk using n (n = 1 or 2) as an index. Exercise form EXER is running RU
If it is N, the process proceeds from step S220 to S221, and in steps S221 and S222, the metabolic demand index X_Sn
(Metabolism demand index by the sensor n (n = 1 or 2) which was in the running) and the heart stimulation rate function frun are selected, and step S2 is performed.
At 50, the target rate Rt is calculated by the cardiac stimulation rate function frun using X_Sn (n = 1 or 2) as an index. Exercise form EXER
Is a stair climbing UPST, then go from step S230 to S
In step S231, the metabolic demand index X_Sn (metabolic demand index by the sensor n (n = 1 or 2) at the stair rise) and the heart stimulation rate function fupst are selected in steps S231 and S232, and in step S250, X_Sn (n = 1 or 2) is used as an index to calculate the target rate Rt with the cardiac stimulation rate function fupst. If the exercise mode EXER is the stair descent DOWNST, the process proceeds from step S240 to S241, and proceeds to step S24.
In steps S1 and S242, a metabolic demand index X_Sn (a metabolic demand index by a sensor n (n = 1 or 2) at a stairs descent) and a heart stimulation rate function fdownst are selected, and in step S250, X_Sn (n =
The target rate Rt is calculated using the heart stimulation rate function fdownst using 1 or 2) as an index. Exercise is exercise form EXER
If NO, the process proceeds from step S260 to S261, and the metabolic demand index X_ is determined in steps S261 and S262.
Then, Sn (a metabolic demand index by a sensor n (n = 1 or 2) corresponding to an external vibration) and a cardiac stimulation rate function fnoise are selected, and in step S250, a cardiac stimulation rate function fnoise using X_Sn (n = 1 or 2) as an index. Is used to calculate the target rate Rt.

As described above, in this embodiment, at least one sensor is selected from two or more sensors for each exercise mode, and the target rate is calculated using the metabolic demand index obtained based on the data of the sensor as an index. It is a feature of the morphology, which allows physiological stimulus rate control.

The following steps S270 to S290 are the same as steps S170 to S190 in FIG. 1C, and a description thereof will be omitted.

In calculating the target rate,
A reference table of the target rate is recorded in advance in the memory, and an address at which the value of the target rate corresponding to the metabolic demand index is recorded is searched based on the metabolic demand index X_Sn, and the address is recorded at that address. It is also possible to derive the value of the target rate. Parameters such as coefficients and reference tables relating to the heart stimulation rate function can be externally changed by a programmer.

In the present embodiment, the processing in the heart stimulation rate function storage section 500, the heart stimulation rate function selection section 600, and the heart stimulation rate calculation section 700 is performed by a software method using a microprocessor. Similar to the first embodiment, the processing in the exercise form discriminating unit 200 and the metabolic demand index calculating unit 300 may be performed by a software method using a microprocessor. In the cardiac pacemaker, what is realized by hardware, What is realized by software, whether a single microprocessor is used, or a plurality of microprocessors are provided in parallel or in series is determined in consideration of processing speed, reliability, and miniaturization. .

Also in the present embodiment, as shown in FIG. 7, if the entire control section is realized by software, it can be realized by an IC chip in which many parts are integrated.

<Third Embodiment> FIG. 3A shows an example of a cardiac pacemaker according to a third embodiment, in which a movement detecting unit is used as one of the metabolic request detecting units, and the outputs of the two metabolic request detecting units. FIG. 5 is a block diagram showing a case where two metabolic requirement indices are calculated from the above, and one metabolic requirement detecting unit and one metabolic requirement index are selected according to the exercise mode.

In this embodiment, similarly to the second embodiment, the motion detecting section 100 includes the first sensor 1c and the first sensor 1c.
It includes a first sensing circuit 2c that amplifies the output of the sensor 1c and outputs it as a digital signal. The exercise detecting unit 100 is commonly used as one of the metabolic demand detecting units. The metabolic demand detecting unit 101 includes a second sensor 10c and a second sensing circuit 11c that amplifies the output of the second sensor 10c and outputs the amplified signal as a digital signal. Here, as the first sensor 1c and the first sensing circuit 2c, a sensor and a sensing circuit that can determine a movement form from the detected information are used. The metabolic demand index is calculated from the information detected by the first sensor 1c and the first sensing circuit 2c, or the metabolic demand index is calculated from the information detected by the second sensor 10c and the second sensing circuit 11c, depending on the detected exercise mode. Judgment as to whether or not to calculate is made, and by selecting a sensor and a sensing circuit suitable for each exercise form, heart stimulation having a high correlation with metabolic demand can be performed.

For example, assuming that a body motion sensor such as a three-axis acceleration sensor is used as the first sensor 1c, FIG.
As shown in (2), when detecting an external vibration (including when no body movement is detected) while riding on a vehicle, a metabolic demand index for determining a heart stimulation rate is obtained from the outputs of the body movement sensor and the sensing circuit. Cannot be calculated. Therefore, when the motion mode is the external vibration (including the non-detection of the body motion), the second sensor 10c and the second sensing circuit 1 that are different from the body motion sensor
It is desired to calculate the metabolic demand index using the information obtained from 1c. Some examples of those sensors and metabolic demand indicators are listed at the beginning of the embodiment. That is,
The combination of the first sensor 1c and the second sensor 10c is
It is desirable to select those whose detection is complementary. still,
In this example, two types of different sensors are used. However, if an increase in the size can be avoided, the reliability can be further improved by using more types of sensors.
In this case, the determination of the exercise mode may be performed based on the detection of a plurality of types of sensors.

Hereinafter, a case where a three-axis acceleration sensor is used as the first sensor 1c will be described as an example. Exercise form discriminator 200
Is composed of a DSP 11 and a register REG3 (6a) for temporarily storing a result of exercise mode discrimination. Motion detection selector 1
Reference numeral 100 denotes a selector SEL11 (12c) for switching the outputs of the acceleration sensing circuit 2c and the second sensing circuit 11c according to the exercise mode EXER.

The metabolic demand index calculating section 300
(13c) and registers REG21 (14e) and REG22 (15e) for temporarily storing the metabolic demand index calculation result. The metabolic requirement index selecting unit 400 stores the registers REG21, REG
Selector SE that switches the output of 22 according to the exercise form EXER
It is composed of L1.

In this embodiment, fwalk (during walking on flat ground), frun (during running), fupst (during stairs rising), fdownst (during stairs falling), fnoise (external vibration detection and body motion non-motion) are used as heart stimulation rate functions. (At the time of detection), and the heart stimulation rate function storage unit 500 stores REG4, REG5, REG6, REG
7 and REG8. The heart stimulus rate function selection unit 600 selects the exercise mode according to the exercise form EXER.
It is composed of a selector SEL2 for switching the outputs of REG4 to REG8. The heart stimulation rate calculation unit 700 is composed of an arithmetic circuit 13a, and calculates the heart stimulation rate using the outputs of SEL1 and SEL2. The cardiac stimulation rate control unit 800 is constituted by a pacing control circuit 14a, and performs appropriate stimulation based on a condition determination that includes the self-heart rate sensing output from the electrocardiographic signal sensing circuit 16a in the cardiac stimulation rate calculated by the arithmetic circuit 13a. Rate pacing trigger output to heart stimulating unit 9
Output to 00. The heart stimulating unit 900 includes the driver circuit 15
The output of the driver circuit 15a is guided to the inside of the heart cavity by a pacing lead (not shown) through the connector section, and stimulates and beats the patient's heart.

Note that the DSP 11 in this embodiment is
For example, the DSP includes the functions of the coordinate conversion unit (49), the acceleration intensity calculation unit (2), and the exercise mode determination unit (46) in FIG.
12 includes a coordinate conversion unit (49) and a step number measurement unit (3). Note that if the DSP of FIG. 5 is a one-chip IC, the DSP 11 and the DSP 12 may use a common chip.

<Modification of Third Embodiment> In FIG. 3A, a case has been described in which each component is configured by hardware. However, FIG. 3B shows a configuration example using a microprocessor as the present embodiment.

In the present embodiment, the motion detection selection section 1100, the metabolic demand index selection section 400, the heart stimulation rate function storage section 500, the heart stimulation rate function selection section 600,
The processing in the heart stimulation rate calculation unit 700 is
The processing is performed by a software method using a microprocessor 1300 including a ROM 310, a ROM 1320, and a RAM 1330.
Also in the present embodiment, the exercise detecting unit 100, the metabolic request detecting unit 101, the exercise form determining unit 200, the metabolic request index calculating unit 300, the heart stimulation rate control unit 800, and the heart stimulating unit 900 are hardware similar to FIG. 3A. It consists of. However, in the metabolic requirement index calculating unit 300 of the present embodiment, the DSPs 121 and 122 are provided to increase the processing speed, and the two metabolic requirement indices are calculated by the detection of the first sensor 1c and the detection of the first sensor 10c. And the calculation of the two metabolic demand indices are performed in parallel.

FIG. 3C and FIG.
3 shows an algorithm of processing in 300. This will be described in detail below.

At step S300, the RAM 1320 of the microprocessor 1300 stores the exercise form EXE from the REG3.
R, REG211 to X_S1_1 (metabolism demand index 1 by first sensor), REG221 to X_S1_2 (metabolism demand index 2 by first sensor), REG212 to X_S2_1 (metabolism demand index 1 by second sensor), REG222 to X_S2_2 (second metabolism demand index) The metabolic demand index 2) by the sensor is read and read into the ROM 1310 or the RAM.
1320 includes a basic rate (R_basic) and a maximum rate (Rm
ax), cardiac stimulation rate (Rpace), rising fluctuation rate (dRu
p), descent rate (dRdown), heart rate function fwa
lk (at the time of parallel walking), frun (at the time of running), fupst (at the time of stairs going up), fdownst (at the time of stairs going down), and fnoise (at the time of detecting extraneous vibration and not detecting body motion) are prepared. It should be noted that the real-time heart stimulation rate (Rpace) is stored in the RAM 1320, but the standard heart stimulation rate and other parameters and functions are determined by RO
It may be stored as fixed data in M1310 or may be rewritably loaded in RAM 1320.

If the exercise mode EXER is walking on level ground walk, the process advances from step S310 to step S311. At steps S311 and S312, the metabolic request index X_Sn_m (the metabolic request by the sensor n (n = 1 or 2) during level ground walking) is determined. The index m (m = 1 or 2)) and the cardiac stimulation rate function fwalk are selected, and in step S350, the target rate Rt is calculated by the cardiac stimulation rate function fwalk using X_Sn_m (n = 1 or 2, m = 1 or 2) as an index. calculate. If the exercise mode EXER is the running RUN, the process proceeds from step S320 to S321, and proceeds to step S321.
And the metabolic demand index X_Sn_m (the sensor
The metabolic demand index m (m = 1 or 2) according to n (n = 1 or 2)) and the cardiac stimulation rate function frun are selected, and in step S350, X_
The target rate Rt is calculated by the cardiac stimulation rate function frun using Sn_m (n = 1 or 2, m = 1 or 2) as an index. If the exercise form EXER is the stair climbing UPST, step S330
From step S331 and S332, the metabolic demand index X_Sn_m (the metabolic demand index m (m = 1 or 2) by the sensor n (n = 1 or 2) at the stairs rise) and the heart stimulation rate function fupst Selected and in step S350 X_Sn_m
The target rate Rt is calculated with the heart stimulation rate function fupst using (n = 1 or 2, m = 1 or 2) as an index. Exercise form E
If XER is down stairs DOWNST, step S340
From step S341 and S342, the metabolic demand index X_Sn_m (the metabolic demand index m (m = 1 or 2) by the sensor n (n = 1 or 2) at the stairs descending) and the heart stimulation rate function fdownst Selected, and X_Sn_
The target rate Rt is calculated using the heart stimulation rate function fdownst using m (n = 1 or 2, m = 1 or 2) as an index. If the exercise mode EXER is a foreign vibration NOISE, step S36
The process proceeds from step S361 to step S361, and steps S361 and S362 are performed.
And the metabolic demand index X_Sn_m (sensor n (n = 1
Or 2) the metabolic demand index m (m = 1 or 2)) and the cardiac stimulation rate function fnoise are selected, and X_Sn
The target rate Rt is calculated by the cardiac stimulation rate function fnoise using _m (n = 1 or 2, m = 1 or 2) as an index.

As described above, the feature of the present embodiment is that the target rate is calculated using at least one metabolic demand index from two or more metabolic demand indexes obtained from two or more sensors for each exercise mode. This allows physiological stimulation rate control.

The following steps S370 to S390 are the same as steps S170 to S190 in FIG. 1C, and a description thereof will be omitted.

In calculating the target rate,
A reference table of the target rate is recorded in advance in the memory, and an address at which the value of the target rate corresponding to the metabolic demand index is recorded is searched based on the metabolic demand index X_Sn_m, and the address is recorded at that address. It is also possible to derive the value of the target rate. Parameters such as coefficients and reference tables relating to the heart stimulation rate function can be externally changed by a programmer.

In the present embodiment, the metabolic demand index selecting section 400, the cardiac stimulation rate function storage section 500, the cardiac stimulation rate function selecting section 600, the cardiac stimulation rate calculating section 700
Was performed by a software method using a microprocessor, but the processing in the exercise form discriminating unit 200 and the metabolic demand index calculating unit 300 was performed by a software method using a microprocessor, as in the first embodiment. In a cardiac pacemaker, what is realized by hardware and what is realized by software, whether a single microprocessor is used, or a plurality of microprocessors are provided in parallel or in series depends on the processing speed. It is determined in consideration of the reliability and the miniaturization.

Also in this embodiment, as shown in FIG. 7, if the entire control unit is realized by software, it can be realized by an IC chip in which many parts are integrated.

Although a plurality of DSPs are used in FIGS. 2A, 2B, 3A, and 3B, the frequency band (sampling rate) required for the motion detection unit is 100 Hz or less. By operating the DSP with a clock that is sufficiently faster than that, it is possible to perform the above-described plurality of processes with one DSP.

The algorithm described in the present embodiment may be stored in a ROM and mounted on a pacemaker.
The data may be written to the RAM in the pacemaker by telemetry from outside. Further, various variables and functions used in the algorithm shown in the present embodiment may be stored in a ROM mounted on the pacemaker in advance, or may be written from outside into the RAM in the pacemaker by telemetry.

Further, in the above embodiment, the average walking speed is used as the metabolic demand index of the cardiac stimulation rate. However, in addition to the average walking speed, the integration amount of the acceleration signal or the body motion signal for a certain time and the average value for a certain time are used. , Fixed time addition value,
It is also possible to use as an index an index that can be obtained by calculating the body vibration such as the maximum amplitude, or biological information such as body temperature and respiratory volume.

For example, the following examples are given as examples of the exercise detecting section and the metabolic demand detecting section (sensor) and of the metabolic demand index.

One-axis or multi-axis piezoresistive, piezoelectric, capacitive acceleration (body motion) sensor, and other body motion sensors: step count (output obtained from sensor and sensing circuit, or filtered output Signals that exceed a certain threshold), body movement (outputs obtained from sensors and sensing circuits, or signals obtained by filtering the outputs, are detected, converted to absolute values, or squared,
Furthermore, integration processing, averaging processing, or addition processing), body motion intensity (output obtained from the sensor and the sensing circuit, or the maximum amplitude value of a signal obtained by filtering the output) Impedance method: respiration rate, once Ventilation volume, minute ventilation volume, stroke volume, stroke volume, time before ejection ・ Temperature sensor: Central venous blood temperature ・ Oxygen saturation sensor: Venous oxygen saturation, arterial oxygen saturation ・ Nerve sensor: Nerve Impulse frequency • Hormone sensor: Blood catecholamine • EMG: EMG pulse amplitude, EMG pulse frequency • Lactate sensor: Blood lactate • Blood gas sensor: Blood oxygen partial pressure, blood carbon gas partial pressure • Blood pressure sensor : Blood pressure value, blood pressure change rate ・ Electrocardiogram: QT interval ・ pH sensor: Blood pH In addition, examples of the exercise form include walking on flat ground, running, ascending stairs, descending stairs, rotating arms, and knees. Bending, lifting luggage, riding a bicycle, walking uphill, running uphill, and the like.

[0094]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-axis acceleration sensor, which is one of the embodiments of the present invention, is used in common by a motion detecting means and a metabolic demand detecting means, and two metabolic demand indexes are calculated.
The effects of selecting one metabolic demand index are shown below. In the present embodiment, the average walking speed is used as the metabolic demand index of the cardiac stimulation rate. Table 4 shows the results of the inventor's calculation of the average walking speed when walking on flat ground using the acceleration in the direction of movement below the collarbone during walking, and the average walking speed when running on flat ground, climbing stairs, and descending stairs using vertical acceleration. Are shown in Table 5.

[0095]

[Table 4]

[0096]

[Table 5]

As shown in Tables 4 and 5, the exercise mode is determined, the average walking speed using the traveling direction acceleration is selected when walking on level ground, and the vertical acceleration is calculated when running on level ground, ascending stairs, and descending stairs. By choosing the average walking speed used, ± 2.3
It was possible to measure the average walking speed with standard deviation within steps / min.

According to this embodiment, walking on level ground, running on level ground,
In order to demonstrate that cardiac stimulation can be performed at a physiological stimulation rate when stairs are ascending and descending, a heart rate and body vibration (acceleration) data were collected by performing an exercise load test with a healthy person. The exercise load test was performed on a flat ground walking load (90 steps / min, 110
Steps / min, 130 steps / min speed walking load), flat ground running load (130 steps / min, 140 step / min speed running loads), stair climbing load (90 steps / min, 110 steps) / Minute, 130 steps / minute speed of each stair climbing), stairs descending load (90 steps / min, 110 steps /
Min, and 130 steps / min speed down each stair). The stairs used for loading the stairs consist of 70 stairs and 5 landings that pass in 3 steps. Exercise tests consist of rest before exercise (4 minutes), exercise, rest after exercise (8 minutes).
Minutes). Exercise load time is the level walking load,
4 minutes for flatland running load, 90 steps for stair climbing load
Minute, 110 steps / min, 130 steps / min
Seconds, about 45 seconds, about 40 seconds. The exercise load test of the above 11 protocols was performed 5 times, and the heart rate immediately before the end of each walking and running was determined and averaged. Table 6 shows the results.

[0099]

[Table 6]

As an example of this embodiment, the average walking speed WC_X using the acceleration in the traveling direction is selected when walking on level ground, and the average walking speed WC_Z using the vertical acceleration is selected when running on flat ground, climbing stairs, and descending stairs. The target rate was calculated by using the values shown in Table 7 for A (coefficient of the linear equation) and B (intercept) of the heart stimulation rate function shown in the above equation (1).

[0101]

[Table 7]

FIG. 4 shows the result of comparing the calculated target rate with the heart rate immediately before the end of the walking and running loads obtained in the exercise load test. Square, round, triangular, and rhombic points indicate the heart rate obtained by the exercise load test, and the straight line indicates the heart rate obtained from the selected average walking speed using the heart stimulation rate function.

Table 8 shows the correlation coefficient R ^ 2.

[0104]

[Table 8]

[0105]

As described above, according to the present invention,
It is possible to provide a cardiac pacemaker capable of stimulating the heart at a physiological stimulation rate, even if the exercise form is variously different, such as walking on a flat ground, running, climbing a stair, descending a stair, and the like.

That is, the exercise mode is discriminated. For example, when walking on level ground, an average walking speed using the acceleration in the traveling direction is selected, and when running, climbing stairs, and descending the stairs, an average walking speed using vertical acceleration is selected. Then, by calculating the heart stimulation rate using a highly accurate average walking speed that matches each exercise form, the heart rate obtained in the exercise load test,
The heart rate calculated from the average walking speed by the heart stimulation rate calculation function is a high correlation coefficient R ^ 2 of 0.9 or more for all exercise forms.
Could be correlated.

Thus, a cardiac pacemaker (“Body motion detection method and device”) (Japanese Patent Application No. 9-1003) capable of discriminating the motion form (walking on the ground, running, climbing stairs, descending stairs).
06, Applicant: Cardiopacing Research Co., Ltd.
Laboratory), which automatically selects one of two or more metabolic demand indices according to the determined exercise mode and calculates a cardiac stimulation rate, thereby obtaining a physiological rate. Heart stimulation at a reasonable stimulation rate has become possible.

[0108]

[Brief description of the drawings]

FIG. 1A is a diagram showing an example in which a three-axis acceleration sensor is used in common by a motion detecting means and a metabolic demand detecting means, and two metabolic demand indexes are calculated;
It is a block diagram which constituted the cardiac pacemaker of 1st Embodiment which selects one metabolic demand parameter | index according to an exercise form with hardware.

FIG. 1B illustrates a cardiac pacemaker of the first embodiment;
FIG. 2 is a block diagram including hardware and a microprocessor.

FIG. 1C is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 1B.

FIG. 1D is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 1B.

FIG. 2A is a diagram illustrating a second example in which the exercise detector is used as one of the metabolic request detectors, one metabolic request detector is selected from the two metabolic request detectors according to the exercise mode, and a metabolic request index is calculated. It is a block diagram which constituted the cardiac pacemaker of an embodiment with hardware.

FIG. 2B illustrates a cardiac pacemaker of a second embodiment;
FIG. 2 is a block diagram including hardware and a microprocessor.

FIG. 2C is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 2B.

FIG. 2D is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 2B.

FIG. 3A shows an example in which the exercise detector is used as one of the metabolic request detectors, two metabolic request indices are calculated from the outputs of the two metabolic request detectors, and one metabolic request detector and 1 are calculated according to the exercise mode. It is a block diagram which constituted the cardiac pacemaker of a 3rd embodiment which selects one metabolic demand index with hardware.

FIG. 3B shows a cardiac pacemaker of a third embodiment;
FIG. 2 is a block diagram including hardware and a microprocessor.

FIG. 3C is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 3B.

FIG. 3D is a flowchart showing the processing of the microprocessor of the cardiac pacemaker of FIG. 3B;

FIG. 4 is a graph showing a result of comparing a target rate calculated using a selected number of steps as a metabolic demand index with a heart rate obtained in an exercise load test.

FIG. 5 is a diagram illustrating a configuration example of a DSP according to the present embodiment.

FIG. 6A is a diagram showing a distribution of measured values of a traveling direction acceleration intensity (XACT) and an acceleration intensity ratio (ZACT / XACT) at the time of walking on level ground, running on level ground, rising stairs, and descending stairs while changing walking speed. is there.

[FIG. 6B] Traveling acceleration intensity (XACT), vertical acceleration intensity (ZA) when walking on level ground, running on level ground, climbing stairs, descending stairs, and riding a bus, car, or train while changing walking speed
FIG. 4 is a diagram showing a distribution of measured values of CT).

FIG. 7 is a diagram showing a configuration example of a pacemaker configured by software of the present embodiment.

Claims (12)

[Claims] 1. A movement detecting means for detecting a movement of a patient, a movement form determining means for determining a movement form based on an output of the movement detecting means, and a metabolic demand detection for detecting a physical quantity reflecting a metabolic demand of the patient. Means, a metabolic demand index calculating means for calculating a plurality of metabolic demand indexes from the output of the metabolic demand detecting means, and a plurality of metabolic demand index calculated by the metabolic demand index calculating means according to the exercise mode determined by the exercise mode determining means. A metabolic demand index selecting means for selecting at least one metabolic demand index from the metabolic demand indexes; and a plurality of cardiac stimulation rate functions corresponding to the plurality of metabolic demand indexes calculated by the metabolic demand index calculating means. The heart stimulus rate function storage means, and selecting the heart stimulus rate function according to the motion mode determined by the motion mode determination means. Heart stimulation rate function calculating means for calculating a heart stimulation rate based on the metabolic demand index selected by the metabolic demand index selecting means and the heart stimulation rate function selected by the heart stimulation rate function selecting means Means, cardiac stimulation rate control means for controlling the rate of cardiac stimulation based on the calculation result of the cardiac stimulation rate calculating means, and cardiac stimulation means for stimulating the heart at the rate of cardiac stimulation. And a cardiac pacemaker. 2. A movement detecting means for detecting a movement of a patient, a movement form determining means for determining a movement form based on an output of the movement detecting means, and a plurality of metabolism detecting physical quantities reflecting a metabolic demand of the patient. Request detecting means, and at least one of the plurality of metabolic request detecting means according to the exercise mode determined by the exercise mode determining means.
Metabolic demand detection selecting means for selecting one metabolic demand detecting means; metabolic demand index calculating means for calculating a metabolic demand index from the output of the metabolic demand detecting means selected by the metabolic demand detecting / selecting means; Means for storing a plurality of heart stimulation rate functions for the metabolic demand index calculated by the means; and selecting the heart stimulation rate function according to the exercise mode determined by the exercise mode determination means. Cardiac stimulation rate function selecting means; a metabolic demand index calculated by the metabolic demand index calculating means from the output of the metabolic demand detecting means selected by the metabolic demand detection / selecting means; Heart stimulus rate calculating means for calculating a heart stimulus rate according to the obtained heart stimulus rate function; Based on the stage of the calculation result, cardiac pacemaker, characterized by comprising a cardiac stimulation rate control means for rate control of the heart stimulator, and a cardiac stimulation device for stimulating the heart rate of the heart stimulator. 3. A movement detecting means for detecting a movement of a patient, a movement form determining means for determining a movement form based on an output of the movement detecting means, and a plurality of metabolisms for detecting a physical quantity reflecting a metabolic demand of the patient. Request detecting means, and at least one of the plurality of metabolic request detecting means according to the exercise mode determined by the exercise mode determining means.
Metabolic demand detection selecting means for selecting one metabolic demand detecting means; metabolic demand index calculating means for calculating a plurality of metabolic demand indexes from the output of the metabolic demand detecting means selected by the metabolic demand detecting / selecting means; A metabolic demand index selecting means for selecting at least one metabolic demand index from a plurality of metabolic demand indexes calculated by the metabolic demand index calculating means in accordance with the exercise mode determined by the determining means; A heart stimulation rate function storage unit in which a plurality of heart stimulation rate functions are stored with respect to the metabolic demand index calculated by the above, and a heart stimulation that selects the heart stimulation rate function according to the exercise mode determined by the exercise mode determination unit Using the output of the metabolic request detecting means selected by the rate function selecting means and the metabolic request detecting and selecting means, A plurality of metabolic demand index calculated by the required index calculation means, a metabolic demand indicator selected by the metabolic demand indicator selecting means, by the cardiac stimulation rate function selected by the cardiac stimulation rate function selection means,
Heart stimulation rate calculation means for calculating a heart stimulation rate; heart stimulation rate control means for performing a heart stimulation rate control based on the calculation result of the heart stimulation rate calculation means; a heart for stimulating a heart at the heart stimulation rate A cardiac pacemaker comprising stimulating means. 4. The cardiac pacemaker according to claim 1, wherein the metabolic demand detecting means or a part thereof is included in the exercise detecting means. 5. The cardiac pacemaker according to claim 1, wherein the exercise mode discriminated by the exercise mode discriminating means includes walking on a flat ground, running, ascending a stair, and descending a stair. 6. The cardiac pacemaker according to claim 1, wherein said motion detecting means has an acceleration sensor capable of independently detecting orthogonal two-axis or three-axis acceleration. . 7. The cardiac pacemaker according to claim 1, wherein the metabolic demand index calculated by the metabolic demand index calculating means includes a step number or a walking speed within a set time. . 8. The cardiac pacemaker according to claim 7, wherein the number of steps or the walking speed within the set time is calculated from the acceleration of the movement of the patient and the acceleration in the vertical direction. 9. A cardiac pacemaker for controlling a rate of cardiac stimulation according to an exercise form, comprising: exercise form discriminating means for discriminating exercise forms including walking on a flat ground, running, climbing stairs, and descending stairs; A heart stimulating means for stimulating the heart at an exercise stimulating rate calculated from a metabolic demand index in accordance with a result of the means discrimination. 10. An exercise sensor comprising: an acceleration sensor capable of independently detecting orthogonal two-axis or three-axis acceleration; and a movement detecting means for detecting a movement of a patient; The cardiac pacemaker according to claim 9, wherein the exercise mode is determined based on the detection result. 11. A method for controlling a cardiac pacemaker that controls the rate of cardiac stimulation in accordance with a form of exercise, wherein the method detects a patient's movement and, based on the detection result, walks on a level ground, runs, steps up, and steps down. A method of controlling a cardiac pacemaker, comprising: determining an exercise form including: (i) stimulating a heart at a heart stimulation rate calculated from a metabolic demand index according to the determination result. 12. A storage medium for storing a control program of a cardiac pacemaker for controlling a rate of cardiac stimulation in accordance with a form of exercise in a computer-readable manner, wherein the control program detects a movement of a patient and detects the movement. A module for determining a movement form including level walking, running, climbing a stair, and descending a stair based on a result; a module for calculating a metabolic demand index based on the detection result; and the metabolic demand index corresponding to the determination result. And a module for calculating a cardiac stimulation rate from the data.