JPH04300521A - Portable type electrocardiograph - Google Patents

Abstract

PURPOSE:To facilitate the elucidation of order of generation of irregular pulses and ischemia, the decision of the degree of profundity, the confirmation of a dosing effect, etc., by providing arithmetic means for the number of heart beats and electrocardiogram parameters, memory means and means for displaying the same on trend graphs by a display instruction. CONSTITUTION:Electrocardiogram signals are sampled at every specified time by the input of an operation key and the electrocardiogram data subjected to digital conversion are taken into a CPU 4 and are stored into a RAM 6. The CPU 4 analyzes the electrocardiogram waveforms by the electrocardiogram data read out of the RAM 6, searches the peak of the R wave to be the end of one heart beat, calculates the number of the heart beats and stores the same in the RAM 6. The data up to the peak of the R waves twice before from the present point of time of the RAM 6 are erased when an ST level is calculated and stored into the RAM 6. A power source turns off to end the measurement by the operation of a suspension key or upon lapse of 24 hours from the start of the measurement. The power source is turned on again and a number of heart beat or ST level trend key is selected by pressing a reproduction key, by which the number of the heart beats or the ST level trend graph is displayed on a liquid crystal display device 8.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is designed to be carried by a patient on a daily basis, to constantly measure electrocardiogram waveform data, and to store the electrocardiogram waveform data at that time when an abnormality occurs. The present invention relates to a constructed portable electrocardiograph.

0002

[Prior Art] In conventional portable electrocardiographs of this type, when a patient notices symptoms such as palpitations or chest pain, electrocardiogram waveform data for several minutes before and after is digitally stored in an IC memory and measured. After completion, the configuration is such that it can be reproduced as an electrocardiogram waveform on the display screen if necessary. Such portable electrocardiographs are used for ``qualitative diagnosis'' to determine whether subjective symptoms are caused by heart disease.

[0003] Apart from such portable electrocardiographs, there is a Holter electrocardiograph that stores all electrocardiogram waveform data while being worn, regardless of the presence or absence of subjective symptoms. This Holter electrocardiograph stores data in the form of analog signals on magnetic tape or compresses it in the form of digital data.
It is designed to be stored in C memory. After 24 to 48 hours of measurement, the Holter electrocardiograph inputs the obtained data into a dedicated analysis device and outputs information such as heart rate and electrocardiogram ST level along with the entire electrocardiogram waveform.
Used for "quantitative diagnosis" of heart disease.

0004

[Problems to be Solved by the Invention] In conventional portable electrocardiographs, the capacity of the IC memory built into the main body is limited, so even if the patient wears the device for more than 24 hours (up to 5 days), However, the only data that could be obtained was electrocardiogram waveform data for several minutes before and after symptoms were noticed. Therefore, although it is possible to make a qualitative diagnosis of whether the subjective symptoms are caused by heart disease, a quantitative diagnosis is not possible because there is no data (circadian variation data) on heart rate, electrocardiogram ST level, etc. over a long period of time. I had the problem that I couldn't do it.

[0005] On the other hand, Holter electrocardiographs require a separate specialized analyzer, and measurement and analysis are performed separately, making them unsuitable for immediate diagnosis in a consulting room. It was something.

[0006] In the medical field, under the above-mentioned actual situation, heart rate and electrocardiogram S, which are parameters related to electrocardiograms, are
There is a need for a portable electrocardiograph that can memorize diurnal fluctuations in T-levels, etc., and display electrocardiogram parameters on the spot in the examination room so that physicians can immediately use them for quantitative diagnosis.

An object of the present invention is to provide a portable electrocardiograph that can meet the above requirements.

[0008]

[Means for Solving the Problems] A first portable electrocardiograph according to the present invention includes an electrocardiogram amplifier that amplifies an electrocardiogram signal obtained from a body surface electrode attached to a patient, and an electrocardiogram amplifier that amplifies an electrocardiogram signal obtained from a body surface electrode attached to a patient. An A/D converter for converting into digital electrocardiogram data, means for temporarily storing the obtained electrocardiogram data, and calculation of electrocardiogram parameters such as heart rate and electrocardiogram ST level based on the stored electrocardiogram data. storage means for storing the electrocardiogram parameters; means for reading out the electrocardiogram parameters in response to a display command and converting them into display data of a trend graph;
The present invention is characterized by comprising display means for displaying the electrocardiogram parameter trend graph.

The second portable electrocardiograph according to the present invention also includes an electrocardiogram amplifier that amplifies electrocardiogram signals obtained from body surface electrodes worn on a patient, and converts the amplified electrocardiogram signals into digital electrocardiogram data. an A/D converter for converting the data into an A/D converter, a means for temporarily storing the obtained electrocardiogram data, and, based on the patient's operation of an event switch, storing electrocardiogram data for a certain period of time before and after the operation as ictal electrocardiogram data. storage means for calculating electrocardiogram parameters such as heart rate and electrocardiogram ST level based on the temporarily stored electrocardiogram data; storage means for storing the electrocardiogram parameters; means for reading ictal electrocardiogram data and converting it into electrocardiogram waveform display data; means for reading the electrocardiogram parameters and converting them into trend graph display data in response to another display command; and the electrocardiogram waveform or electrocardiogram. The present invention is characterized by comprising display means for displaying parameter trend graphs.

0010

[Operation] According to the first portable electrocardiograph according to the present invention, diurnal fluctuations in electrocardiogram parameters such as heart rate and electrocardiogram ST level can be immediately displayed in the form of a trend graph on the display screen. Become.

Further, according to the second portable electrocardiograph according to the present invention, in addition to being able to display ictal electrocardiogram data in the form of an electrocardiogram waveform when the patient feels abnormality as a subjective symptom, the heart rate , diurnal fluctuations in electrocardiogram parameters such as electrocardiogram ST level are displayed on the display screen in the form of a trend graph.

0012

[Embodiment] First Embodiment The first embodiment relates to the above-described first portable electrocardiograph of the present invention, and FIG. 1 is a block diagram showing the configuration of its main parts.

In the figure, 1 is a body surface electrode attached to a patient, 2 is an electrocardiogram amplifier that amplifies the electrocardiogram signal obtained from the body surface electrode 1, and 3 is an electrocardiogram amplifier that converts the amplified analog electrocardiogram signal into digital electrocardiogram data. 4 is a CP which is the central processing unit of the microcomputer.
U, 5 is a ROM that stores programs, and 6 is a RAM (IC memory) as a working memory.

The RAM 6 has a storage area for temporarily storing electrocardiogram data obtained by the A/D converter 3 via the CPU 4. The CPU 4 calculates the heart rate and electrocardiogram ST based on the electrocardiogram data temporarily stored in the RAM 6.
It has a function to calculate electrocardiogram parameters such as levels. The RAM 6 has an area for storing data on calculated electrocardiogram parameters, ie, heart rate and ST level. The RAM 6 is configured to have a capacity sufficient to store at least two heartbeats' worth of electrocardiogram data and 24 hours' worth of heart rate and ST level data. Further, the CPU 4 has a function of reading heart rate and ST level data from the RAM 6 and converting it into display data of a trend graph.

7 is a liquid crystal driver driven and controlled by the CPU 4; 8 is a liquid crystal display device constructed by arranging minute liquid crystal display elements in a matrix in the vertical and horizontal directions so as to be able to display various data in the form of numerical values, graphs, or waveforms; 9 is a touch key for inputting various commands. Note that 10 indicated by a chain line is an event switch according to a second embodiment, which will be described later, but is irrelevant to the first embodiment.

Next, the operation of the portable electrocardiograph according to the first embodiment will be explained based on the flowcharts shown in FIGS. 2 and 3.

Control operations by the CPU 4 are started when the power is turned on. Detected by body surface electrode 1 and sent to electrocardiogram amplifier 2
The electrocardiogram signal amplified by is input to the A/D converter 3. The CPU 4 performs the following control operations according to the program imported from the ROM 5.

First, in step S1, it is determined whether or not the measurement key in the touch key 9 has been operated. If it is determined that the measurement key has been operated, the routine of steps S2 to S12 is executed, and if not, the touch key is not pressed in step S13. It is determined whether the playback key in the key 9 has been operated, and if it is determined that the playback key has been operated, steps S14--
The routine of S19 or the routine of S20 to S25 is executed (details will be described later).

Generally, the measurement key is inputted first. Therefore, the process advances to step S2 to control the A/D converter 3, sample the amplified electrocardiogram signal inputted by the A/D converter 3 at fixed time intervals, convert it into digital electrocardiogram data by A/D conversion, and send it to the CPU.
Incorporate into 4. Then, the CPU 4 transfers the continuously sampled electrocardiogram data to the RAM 6 and temporarily stores it in step S3.

[0020] Next, in step S4, the CPU 4
The electrocardiogram waveform is analyzed based on the electrocardiogram data read from M6 to search for the peak of the R wave that marks the end of one heartbeat. The R wave apex is the part with the sharpest rise in the QRS complex, which is a characteristic point of the electrocardiogram waveform. The method of searching for the peak of the R wave is, for example, by determining that the electrocardiogram data at a certain point exceeds 70% of the maximum value of the previous electrocardiogram data group and is the maximum point. can. When it is recognized that it is the R wave peak, step S5
If not, the process returns to step S2 via steps S11 and S12, and hereafter steps S2 to S4
, S11, and S12 are repeated.

[0021] Once the R-wave peak is found, the process proceeds to step S5, where the heart rate is calculated. That is, the reciprocal of the time from the R-wave apex of the previous heartbeat to the R-wave apex of the current heartbeat is determined, and this is taken as the heart rate. The time is determined by [sampling number x sampling period] between the peaks of both R waves. Next, the CPU 4 transfers the heart rate data to the RAM 6 and stores it in step S6.

[0022] In step S7, it is determined whether or not the calculation of the ST level has been completed, and if it has been completed, the process proceeds to step S11.
However, if it is not calculated, skip to steps S8 and S9.
Proceed to calculate the ST level. That is, step S
In step 8, it is determined whether a certain period of time (for example, 60 msec) has elapsed since the R wave peak, and if it has elapsed, step S is performed.
Proceed to step 9 to calculate the ST level. The ST level can be determined as a value obtained by subtracting the value of electrocardiogram data at that time from the value of electrocardiogram data a certain time before the R-wave peak (for example, 120 msec before). Once the calculation of the ST level is completed, the data up to the peak of the R wave two times before the current time among the ECG data stored in the RAM 6 will no longer be necessary for the calculation of the heart rate and the ST level. Delete such data in consideration of its effective use. Then, in step S10, ST
The level data is transferred to RAM 6 and stored.

As described above, the heart rate and ST level for one heartbeat have been calculated and stored in the RAM 6. Such calculation and storage of heart rate and ST level data is repeated until the stop key is operated or 24 hours have elapsed from the start of the measurement.

That is, in step S11 the touch key 9
When it is determined that the stop key has been operated, the process returns to step S1, and when it is determined that 24 hours have elapsed in the measurement time at step S12, the power is automatically turned off and the electrocardiogram data measurement is ended. do. Unless the stop key is operated during the process, heart rate and ST level data for each heartbeat over a period of up to 24 hours will be saved.
It will be stored in AM6.

[0025] After the abort key is operated, or 24
When the power is turned on again after a period of time has elapsed, the determination in step S1 is usually negative, and step S1 in FIG.
Proceed to step 3. That is, in step S13, the touch key 9
Wait for the playback key (trend playback key) to be pressed, and then, in steps S14 and S20, it is determined whether the heart rate trend key or the ST level trend key in the touch key 9 is selected, In the former case, the routine of steps S14 to S19 is executed, and in the latter case, the routine of steps S20 to S25 is executed.

[0026] When the heart rate trend is selected in step S14, the process advances to step S15, where the heart rate data is loaded from the RAM 6 into the CPU 4, and in step S16, the heart rate data is converted into a form of display data of a heart rate/trend graph. Convert. This heart rate/trend graph is a graph that shows temporal fluctuations in heart rate, with time on the horizontal axis and heart rate on the vertical axis. Then, in step S17, the CPU 4 transfers the display data of the heart rate/trend graph to the liquid crystal driver 7, and in step S18, controls the liquid crystal driver 7 to display the heart rate/trend graph on the liquid crystal display device 8 (Fig. (see below for details). The display continues until it is determined in step S19 that the cancel key on the touch keys 9 has been operated.

On the other hand, when the ST level trend is selected in step S20, the process proceeds to step S21, where the ST level data is loaded from the RAM 6 into the CPU 4, and in step S22, the ST level data is added to the display data of the ST level trend graph. Convert to shape. This ST level trend graph shows time on the horizontal axis and S on the vertical axis.
This is a graph showing the temporal fluctuations of the ST level based on the T level. Then, in step S23, the CPU
4 transfers the display data of the ST level trend graph to the liquid crystal driver 7, and in step S24 controls the liquid crystal driver 7 to display the ST level trend graph on the liquid crystal display device 8. The display continues until it is determined in step S25 that the stop key has been operated.

FIG. 4 shows an example of a heart rate/trend graph displayed on the liquid crystal display device 8. As shown in FIG.

The liquid crystal display device 8 in the portable electrocardiograph is as follows:
Display resolution is relatively coarse. In the case of this embodiment, for example,
The number of pixels of the liquid crystal display element is 80 dots x 128 dots.

[0030] Therefore, when trying to display a trend graph for the entire measurement time (up to 24 hours), it is necessary to set the unit in the time axis direction to several minutes to several tens of minutes. The average value is calculated and the average value is displayed in a graph.

In the case of FIG. 4(a), the heart rate for 24 hours
A trend graph is displayed, and the unit in the time axis direction may be 24×60/128=11.25 minutes/dot. In other words, the average value of heart rate data for 11.25 minutes may be displayed as one dot. Figure 4(b)
In this case, a heart rate/trend graph for 60 minutes is displayed, and the unit in the time axis direction is approximately 28 seconds/dot. In the case of FIG. 4(c), a heart rate/trend graph for 10 minutes is displayed, and the unit in the time axis direction is approximately 4.7 seconds/dot.

[0032] The same applies to the ST level trend graph, and selection of such display accuracy is performed in step S14.
This is performed by key operation in S20, and calculation of display accuracy is performed in steps S16 and S22.

[0033] In the examination room, the doctor can instantly display the heart rate/trend graph or ST level/trend graph on the liquid crystal display device 8 by operating the touch keys 9 of the portable electrocardiograph. Diurnal fluctuations in numbers and ST levels can be easily recognized. Look at the displayed data to determine the frequency of occurrence of arrhythmia and ischemia.
The time and history of occurrence can be determined, making it useful for quantitatively diagnosing heart disease independent of the patient's subjective symptoms. Also,
It can also be effectively used to elucidate the developmental mechanism, determine severity, and confirm the effectiveness of medication.

Second Embodiment The second embodiment relates to the second portable electrocardiograph of the present invention described above, and the block diagram showing the configuration of the main parts is similar to that of the first embodiment. The event switch 10 shown in dashed lines in FIG. 1 can be represented as being added.

The RAM 6 can store electrocardiogram data for a total of two minutes before and after the input operation of the event switch 10 as ictal electrocardiogram data.
As in the embodiment, it is configured to have a capacity sufficient to store 24 hours worth of heart rate and ST level data.

[0036] The operation of the portable electrocardiograph of the second embodiment is as follows.
The process will be explained using the flowcharts shown in FIGS. 2 and 3 used in the embodiment, as well as the flowcharts shown in FIGS. 5 and 6.

The difference from the first embodiment is that step S3 in FIG. 2 is changed to FIG. 5 due to the addition of the event switch 10.
The two points are that the method is changed to a memory loop method as shown in FIG. 6, and that step S13 between step S1 and step S14 is changed as shown in FIG.

First, the flow shown in FIG. 5 will be explained. In step S3-1, similar to step S3 in FIG.
The electrocardiogram data converted into digital data by the /D converter 3 is transferred to the waveform measurement buffer area of the RAM 6 and temporarily stored therein. In step S3-2, it is determined whether or not event storage based on the operation of the event switch 10 has been completed. If it has not been completed, the process proceeds to step S3-3, but if it has been completed, step S4 in FIG. Skip to Vertex Search).

[0039] In step S3-3, the CPU 4
The event buffer area in M6 is updated and stored so that the electrocardiogram data for the latest one minute is always stored in a secured state. The stored contents are constantly changing until the event switch 10 is operated.

Now, in step S3-4, it is determined whether or not the event switch 10 has been operated. If the event switch 10 has not been operated, the process skips to step S4, but if it has been operated, the process proceeds to step S3-5 and the latest 1-minute data in the RAM 6 is stored. The update storage of the electrocardiogram data is stopped, and the electrocardiogram data for the latest one minute stored at that time is fixedly stored in the event buffer area of the RAM 6. Further, electrocardiogram data for one minute thereafter is fixedly stored in the event buffer area. As described above, when the patient operates the event switch 10 due to a subjective symptom, electrocardiogram data for a total of two minutes, one minute before and one minute before and after the operation, is stored in the RAM 6 as ictal electrocardiogram data. Then, in step S3-6, a flag indicating completion of event storage is set.

From this point on, the process skips from step S3-2 to step S4, so the operation is the same as in the first embodiment. In other words, unless the abort key is operated during the process,
Heart rate and ST for each beat over up to 24 hours
Level data will be stored in the RAM 6.

[0042] After the abort key is operated, or 24
When the power is turned on again after a period of time has elapsed, the determination in step S1 is usually negative, and step S1 in FIG.
3-1 or step S13-2. That is, it waits to see whether the touch key 9 is operated with the event reproduction key or the trend reproduction key. Step S
The determination of the trend playback key input in step 13-2 is the same as the determination of the playback key input in FIG. 3, and is only called as such in the second embodiment to distinguish it from the event playback key input.

When the event reproduction key is operated, the process proceeds to step S13-3, where the ictal electrocardiogram data is read into the CPU 4 from the RAM 6, and the ictal electrocardiogram data is converted into waveform display data at step S13-4. Step S
In step S13-5, the display data of the ictal electrocardiogram waveform is transferred to the liquid crystal driver 7, and in step S13-6, the liquid crystal driver 7 is controlled to display the ictal electrocardiogram waveform on the liquid crystal display device 8. This display continues until it is determined in step S13-7 that the cancel key on the touch keys 9 has been operated. A display example of the ictal electrocardiogram waveform is shown in FIG. When the stop key is operated, the process returns to step S1.

[0044] The doctor displays the liquid crystal display device 8 in the examination room.
By displaying the electrocardiogram waveform at the time of attack, qualitative diagnosis can be made as to whether the subjective symptoms at that time are due to heart disease.As in the first embodiment, the heart rate, trend graph, ST level, A trend graph is immediately displayed on a liquid crystal display device 8 to perform quantitative diagnosis of heart disease independent of the patient's subjective symptoms.

[0045]

As described above, according to the first portable electrocardiograph of the present invention, a doctor can display electrocardiogram parameters such as the patient's heart rate and electrocardiogram ST level by giving necessary display commands. Since daily fluctuations can be displayed in the form of a trend graph on the spot (examination room),
Quantitative diagnosis of heart disease can be performed instantly and easily. In other words, by comparing the displayed trend graph with the patient's behavior during that period, it is possible to easily know the frequency, time, and history of occurrence of arrhythmia and ischemia, and to elucidate the mechanism of occurrence. It can be used extremely effectively for determining severity and confirming the effectiveness of medication.

Furthermore, according to the second portable electrocardiograph according to the present invention, by displaying ictal electrocardiogram data based on the patient's subjective symptoms in the form of an electrocardiogram waveform, it is possible to determine whether the symptoms are caused by a heart disease. In addition to being able to make a qualitative diagnosis of
Similarly to the above, by displaying diurnal fluctuations in electrocardiogram parameters such as heart rate and electrocardiogram ST level, which are not affected by the presence or absence of subjective symptoms of the patient, in the form of a trend graph,
Quantitative diagnosis of heart disease can also be performed immediately and easily in the examination room.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of main parts of a portable electrocardiograph according to a first embodiment.

FIG. 2 is a flowchart for explaining the operation of the first embodiment.

FIG. 3 is a flowchart for explaining the operation of the first embodiment.

FIG. 4 is a diagram showing a display example of a heart rate/trend graph according to the first embodiment.

FIG. 5 is a flowchart for explaining the operation of the portable electrocardiograph according to the second embodiment.

FIG. 6 is a flowchart for explaining the operation of the second embodiment.

FIG. 7 is a diagram showing a display example of an ictal electrocardiogram waveform according to a second embodiment.

[Explanation of symbols]

1 Body surface electrode 6
RAM2 ECG amplifier
7 LCD driver 3 A/D
Converter 8 Liquid crystal display device 4
CPU
9 Touch key 5 ROM
10 Event switch

Claims (2)

[Claims] Claim 1: An electrocardiogram amplifier that amplifies an electrocardiogram signal obtained from a body surface electrode attached to a patient, and an amplifier that converts the amplified electrocardiogram signal into digital electrocardiogram data.
A D converter, means for temporarily storing the obtained electrocardiogram data, means for calculating electrocardiogram parameters such as heart rate and electrocardiogram ST level based on the stored electrocardiogram data, and storing the electrocardiogram parameters. a storage means for reading the electrocardiogram parameters according to a display command and converting them into display data of a trend graph; and a display means for displaying the electrocardiogram parameters and trend graph. Electrocardiograph. 2. An electrocardiogram amplifier that amplifies an electrocardiogram signal obtained from a body surface electrode attached to a patient, and an amplifier that converts the amplified electrocardiogram signal into digital electrocardiogram data.
a D converter, a means for temporarily storing the obtained electrocardiogram data, and a storage means for storing electrocardiogram data for a certain period of time before and after the operation of the event switch by the patient as ictal electrocardiogram data; means for calculating electrocardiogram parameters such as heart rate and electrocardiogram ST level based on the temporarily stored electrocardiogram data;
storage means for storing the electrocardiogram parameters; means for reading out the ictal electrocardiogram data in response to a display command and converting it into display data of an electrocardiogram waveform; and means for reading out the electrocardiogram parameters in response to another display command and trending them. A portable electrocardiograph comprising means for converting into graph display data and display means for displaying the electrocardiogram waveform or electrocardiogram parameter trend graph.