JPH0479255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arterial wave propagation analysis device used for diagnosing circulatory system diseases by analyzing the state of propagation of arterial waves from the central region to the periphery.

[Conventional technology]

Regarding the analysis of the pulse wave propagation state, the waveform of the heart sound or electrocardiogram and the pick-up waveform of the pulse wave are drawn on the same recording paper, and each waveform is analyzed to calculate the distance between specific positions along the circulatory system. A well-known method is to measure the pulse wave propagation time using a scale, convert it into a pulse wave propagation time, and then measure the arterial wave propagation velocity by taking the body length into consideration. Furthermore, in order to save labor and measurement time, a partially automated aortic wave velocity measuring device has been proposed (Japanese Patent Publication No. 57-6930).

[Problem that the invention seeks to solve]

However, although it is known that the state of arterial sclerosis can be determined to some extent by such velocity measurements, the state of arterial wave propagation is not actively used to diagnose various diseases in the clinical field of the circulatory system or vascular system. No equipment exists to do so.

In the present invention, the electrophysiological phenomenon of cardiac contraction does not correspond to the starting point of the arterial wave at the arterial origin itself, and it is difficult to measure the true arterial wave propagation time.
Furthermore, since the distance from the arterial root to the periphery is not constant due to individual differences and how limbs are selected, it is important to recognize that this time itself has little practical diagnostic value. Arterial wave propagation analysis non-invasively and automatically analyzes the distribution of pulse wave transit times, focusing on the fact that the magnitude of "fluctuations" in pulse wave transit times can be used as a diagnostic index for circulatory system diseases through statistical analysis. The purpose is to provide equipment.

[Means for solving problems]

In order to achieve this object, the present invention, as shown in FIG. 1, includes an electrocardiogram signal detection means 1 that detects and amplifies an electrocardiogram signal induced from an electrode attached to the chest or other body part; R-wave detection means 2 detects R-waves in the detected electrocardiogram signal and outputs an R-wave timing signal at the time of detection, and a plethysmograph, pulse oximeter, etc., which is attached to a peripheral blood vessel and detects arterial waves. pulse wave detection means 3; pulse wave peak detection means 4 for detecting the top or bottom peak of the detected arterial wave and outputting a peak timing signal at the time of this detection;
Pulse wave propagation time measuring means 5 sequentially measures the time interval from the input of the wave timing until the input of the peak timing signal, and the distribution of the pulse wave propagation time so that fluctuations in the pulse wave propagation time over a predetermined time can be seen. It consists of pulse wave propagation analysis means 6 for analyzing the state, and output means 8 for displaying or recording the analysis results of this analysis means.

In order to detect the incidence of so-called "dry firing" in which pulse waves do not propagate to the periphery or do not propagate beyond a certain level despite contraction of the myocardium, there is a difference between the R-wave timing signals output from the R-wave detection means. It is also conceivable to provide a blank firing analysis means 7 for analyzing the degree of blank firing in which the peak timing signal output from the pulse wave peak detection means is not input.

[Effect]

The R-wave detection means 2 sequentially detects R-waves in the detected electrocardiogram signal and outputs an R-wave timing signal indicating the point in time. On the other hand, the pulse wave peak detection means 4 detects the top or bottom in the arterial wave signal that occurs after the generation of the electrocardiogram signal, and outputs a peak timing signal indicating that point. Thereby, the pulse wave propagation time measuring means 5 measures the so-called pulse wave propagation time between the R wave timing signal and the peak timing signal each time an electrocardiogram signal is generated. The pulse wave propagation analysis means 6 analyzes the distribution state of each pulse wave propagation time for a predetermined time so that fluctuations in the pulse wave propagation time over a predetermined time can be confirmed by displaying trends of amplitude waveforms, displaying histograms, calculating standard deviations, etc. Then, the output means 8 displays or records the results.

The dry hitting analysis means 7 detects the absence of a peak timing signal between the R-wave timing signals as a dry hitting, and determines the degree of dry hitting as a ratio of the number of dry hitting for a predetermined time or the detected pulse wave number or the number of dry hitting to the heart rate. The analysis result is outputted to the output means 8. body length 1 for the R-wave timing signal interval, which is typically 600-1000 ms.
The arterial wave propagation time for m is normally 100 to 350 ms, so even if we take into account the time it takes for the arterial wave to rise from the R wave, which is an electrical signal representing contraction of the left ventricular myocardium, to the aortic root, the peripheral The arterial wave signal wave at is normally reliably discriminated from the next R wave signal without interfering with the electrocardiogram signal.

[Embodiments of the invention]

FIG. 2 shows a circuit configuration of an arterial wave propagation analysis device according to an embodiment of the present invention.

In the figure, 10 is an electrode 1 attached to the chest.
An electrocardiogram signal amplifier that amplifies the electrocardiogram signal induced from 0a; 11 is an R-wave detection circuit that detects the R-wave in the electrocardiogram signal a and outputs an R-wave timing signal b at that point; and 12 is an R-wave timing signal. b
13 is a latch circuit that holds the counted value immediately before being reset each time the R-wave timing signal b is input. be.

15 is a pick-up 15 attached to the fingertips of the hand.
a fingertip pulse wave detector that detects arterial waves in cooperation with a;
16 is a bottom detection circuit that detects the bottom of the arterial wave c by differentiation and outputs a bottom (lowest level) timing signal d at that point, and 17 is a pulse wave interval that counts the clock CK input between the bottom timing signals d. The measuring circuit 18 is a latch circuit that holds the count value immediately before being reset every time the bottom timing signal d is input.

20 is a counter that counts the input R-wave timing signal b until the reset signal RS of, for example, two minutes intervals is supplied from the timing signal generation circuit 29, and 20a is a counter that similarly counts the bottom timing signal d. , 21 is a blank hitting rate calculation circuit 22 which calculates the blank hitting rate for each 2 minute interval by dividing the counted value of the counter 20 as the denominator and the counted value of the counter 20a as the numerator;
is a numerical display that numerically displays the blank firing rate.

23 is a pulse pulse that measures the time corresponding to the arterial wave propagation time from the heart to the finger by counting the input clock CK between the input of the R wave timing signal b and the input of the bottom timing signal d. The wave propagation time measuring circuit 24 is a latch circuit that latches the count value immediately before the R wave timing signal b is input.

26 is a blank firing detection circuit which outputs a pulsed blank firing signal if the bottom timing signal d is not input while the next R wave timing signal b is input;
Reference numeral 7 denotes a light emitting body which notifies blank firing by emitting light in response to the blank firing signal. 28 is a cathode ray tube monitor, which receives an electrocardiogram signal a and a pulse wave signal b.
In addition to displaying the waveform, the latch circuits 13, 18,
The digital signal taken in from 24 is converted into an analog amplitude along the vertical axis, and displayed in a bar graph format with the elapsed time of 2 minutes as the horizontal axis. Each of these parts 2
2, 27, and 28 constitute analysis result output means according to the present invention.

The operation of the arterial wave propagation analysis apparatus configured as described above will be explained with reference to FIGS. 3 and 4.

When starting measurement, the timing signal generation circuit 29
When the operation start signal is input to
is output to reset each section 20, 20a, 21, and start generating the clock CK. The R-wave detection circuit 11 detects the R-wave in the input electrocardiogram signal a using a well-known method and outputs an R-wave timing signal b.
The R-wave interval measuring circuit 12 counts the clock CK during this period, and when the next R-wave timing signal b is input, the latch circuit 13 holds the count value at that time as R-wave interval data and starts counting again.

The bottom detection circuit 16 detects the bottom of the input arterial wave c and outputs a bottom timing signal d. During this period, the pulse wave interval counter 17 clocks CK.
When the next bottom timing signal d is input, the latch circuit 18 holds the count value at that time as pulse wave interval data and starts counting again.

The pulse wave propagation time measurement circuit 23 counts the clock CK after the input of the R wave timing signal b, and when the bottom timing signal d is input, the latch circuit 24 holds the counted value as pulse wave propagation time data. When the wave timing signal is input, counting starts again.

While this operation continues, the cathode ray tube monitor 28 displays the electrocardiogram signal a and the arterial wave signal c at an appropriate sweep speed, and the latch circuit 1
The R wave interval, pulse wave interval, and propagation time data held in 3, 18, and 24 are successively converted into analog pulse waveforms in the vertical axis direction corresponding to the levels, and the data is sequentially shifted downward at a slower sweep speed and displayed. do. The blank firing detection circuit 26 causes the light emitter 27 to instantaneously emit light every time blank firing is detected. After operation starts 2
When the minute has elapsed, a reset signal RS is generated, and the blank firing rate calculation circuit 21 performs division, holds the result until the next reset signal RS is input, and displays the value on the numerical display 2.
Display on 2. On the other hand, on the cathode ray tube monitor 28, fluctuations in the R wave interval, pulse wave interval, and pulse wave propagation time during this two-minute period can be seen from the fluctuations in their respective envelopes (in Figure 4, the number of analog pulse waveforms in the vertical axis direction is calculated from the actual number). (shown below).

According to this embodiment, by setting the fingertip at the periphery, it is particularly effective for diagnosing the condition of the arterial wall from the aorta to the peripheral artery, that is, arteriosclerosis. Furthermore, in this embodiment, the blank firing rate calculation circuit 21
is the output signal of the blank firing detection circuit 26 to the counter 2.
0a may be counted and the molecule input may be used. The data of the latch signals 13, 18, and 24 can be taken into the CPU for statistical processing, and histogram data for each predetermined time interval can be created and displayed on a cathode ray tube (see Figure 5), or the average value and its corresponding It is also possible to calculate the standard deviation and output it numerically. The bottom detection circuit 16 is provided with a gate generation circuit that is triggered by the R wave timing signal b with a predetermined time delay and that generates a gate that defines a period during which an arterial wave originating from the same heartbeat as the R wave may occur. By following an AND gate and using the bottom timing signal b as one input and this gate signal as the other input, it is possible to remove noise signals such as arterial waves that are not derived from the same heartbeat. It is also conceivable that this gate generation circuit makes the bottom detection circuit 16 inoperable during this period as a gate signal of opposite polarity.

〔Effect of the invention〕

As described above, according to the present invention, the so-called propagation time of arterial waves from the center to the periphery is detected, and diagnostic information not only for arteriosclerosis but also for a wider range of circulatory system diseases is obtained from fluctuations in the propagation time data obtained for a predetermined time. is obtained. In other words, the fluctuation is stable and stable, and the fluctuation is less than normal, compared to the normal state where it fluctuates greatly due to loads such as breathing movements and body changes, and there is little fluctuation due to loads such as body changes. By checking this, it is possible to diagnose autonomic nerve imbalance caused by severe diabetes, etc., and the extent of organic changes caused by arteriosclerosis can be determined by the constant small fluctuations. It is believed that this will lead to further development of clinical applications of pulse wave propagation parameters in the future.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an arterial wave propagation analysis device according to the present invention, FIG. 2 is a diagram showing the configuration of an arterial wave propagation analysis device according to an embodiment of the present invention, and FIG. 3 is a diagram showing the operation of each part of the same embodiment. FIG. 4 is a diagram showing the display state of the cathode ray tube monitor of the same embodiment, and FIG. 5 is a diagram showing the display state of the cathode ray tube monitor according to another embodiment.

Claims (1)

[Scope of Claims] 1. Electrocardiogram signal detection means for detecting electrocardiogram signals by electrodes attached to the chest or other body parts;
R-wave detection means for detecting an R-wave in the detected electrocardiogram signal and outputting an R-wave timing signal at the time of this detection; a pulse wave detection means for detecting an arterial wave by being attached to a peripheral blood vessel; pulse wave peak detection means for detecting the top or bottom peak of the arterial wave and outputting a peak timing signal at the time of this detection; Pulse wave propagation time measuring means for sequentially measuring time intervals as pulse wave propagation times, and pulse wave propagation analysis for analyzing the distribution state of the pulse wave propagation times so as to understand fluctuations in the pulse wave propagation times over a predetermined time. What is claimed is: 1. An arterial wave propagation analysis device comprising: means; and output means for displaying or recording the analysis results of the analysis means. 2. Claim No. 2 comprising a blank firing analysis means for analyzing the degree of blank firing in which the peak timing signal output from the pulse wave peak detecting means is not input between the R wave timing signals output from the R wave detecting means. The arterial wave propagation analysis device according to item 1. 3. The arterial wave propagation analysis device according to claim 1, wherein the output means displays or records a histogram of R wave timing intervals and a histogram of peak timing intervals of the top or bottom of the arterial wave. 4. Gate generation means for generating a gate that defines a period in which an arterial wave originating from the same heartbeat as the R wave is likely to occur from a point delayed by a predetermined time from the point in time when the R wave timing signal is generated, and the pulse wave peak 2. The arterial wave propagation analysis device according to claim 1, wherein the detecting means generates a peak timing signal only for pulse wave peaks occurring during the period.