JPH04352941A - Portable electrocardiograph - Google Patents

Abstract

PURPOSE:To perform quantitative diagnosis based on a fluctuation in a day by providing a portable electrocardiograph capable of regenerating and confirming constantly latest information and an electrocardiogram waveform at an abnormal period as the generating frequency of abnormal electrocardiogram data provided at intervals of a specified unit time in a dispensary room or a sickroom. CONSTITUTION:An electrocardiogram signal picked up by a sensor part 2 is converted into electrocardiogram data through an amplifying part 4 and an A/D converting part 6 to input it in an CPU 8 and store it in an RAM 12. An electrocardiogram waveform is analyzed based on the electrocardiogram data to search an R-wave apex being the end of one heart beat. An R-R distance between present and preceding heart beats and the rate of change of the distance value are calculated, by comparing the rate of change with a given value, it is decided whether it is abnormal electrocardiogram data caused by ventricular extrasystole, and an alarming device 20, such as a buzzer, is operated. Thereafter, the generating frequency of repeat abnormal electrocardiogram data is updated and stored. When a regeneration key is operated, the generating frequency and an electrocardiogram waveform at an abnormal period are regenerated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention constantly measures electrocardiogram data of patients (particularly hospitalized patients), stores the electrocardiogram data at that time when an abnormality occurs, and reproduces it as necessary. The present invention relates to a constructed portable electrocardiograph.

0002

2. Description of the Related Art Conventionally, a Holter electrocardiograph has been known as a device for recording electrocardiogram data of a patient over a long period of time. A Holter electrocardiograph must be carried by the patient at all times.
Electrocardiogram data over a continuous 24-hour period is recorded on magnetic tape in the form of analog signals.

The general configuration of the Holter electrocardiograph is shown in FIG. 8. By operating a switch 32, a magnetic tape 36 is run through a drive section 34, and an electrocardiogram signal picked up by a sensor section 38 is transmitted to an amplification section 40. The signal is amplified and recorded on the magnetic tape 36 via the recording head 42.

[0004] After completing the continuous 24-hour measurement,
The obtained data is input into a dedicated analysis device and analyzed continuously for 24 days.
By displaying or printing progress data over time, it is used for "quantitative diagnosis" of heart disease.

The schematic configuration of the analysis device is shown in FIG.
The electrocardiogram signal is picked up from the magnetic tape 36 by the reproducing head 46 while the magnetic tape 36 is traveling by the driving part 44, and after being amplified by the amplifying part 48, the A/D converter 5
0 into digital electrocardiogram data, which is displayed on the display unit 54 via the microcomputer 52 or printed by the printer 56.

On the other hand, apart from Holter electrocardiographs, portable electrocardiographs have been known for some time. This portable electrocardiograph is carried by the patient at all times, and when the patient notices symptoms such as palpitations or chest pain, it digitally stores electrocardiogram data for several minutes before and after the onset of symptoms, and the measurement ends. It is configured so that it can be later reproduced as an electrocardiogram waveform on a display screen if necessary. Such portable electrocardiographs are used for ``qualitative diagnosis'' to determine whether subjective symptoms are caused by heart disease.

[0007]

[Problems to be Solved by the Invention] In the case of a Holter electrocardiograph, once continuous 24-hour measurement recording is completed, no further measurement recording is performed. In other words, even if it is continuous 24-hour recording, it is recorded within a certain limited period. For example, when measurement recording ended one day ago, even if electrocardiogram data for 24 consecutive hours up to the end point was recorded, electrocardiogram data after that end was not recorded. The same applies when measurement recording is finished 1 hour or 10 minutes ago.

[0008] Even if a 48-hour tape is used to lengthen the recording time, no recording will be performed after 48 hours of continuous recording, and the same thing will happen in the end.

Furthermore, in the case of Holter electrocardiographs, a dedicated analysis device is required separately, and measurement and analysis are performed separately, making them unsuitable for immediate diagnosis in a consulting room. there were.

On the other hand, portable electrocardiographs have a limited capacity of IC memory built into the main body, so even if the patient wears it for more than 24 hours (up to 5 days),
The only data available was electrocardiogram data for several minutes before and after symptoms were noticed. As a result, although it is possible to qualitatively diagnose whether the subjective symptoms are caused by heart disease, it is not possible to make a quantitative diagnosis based on diurnal fluctuations because long-term trend parameters related to electrocardiograms are not stored. There was a problem.

In the medical field, under the above-mentioned circumstances, it is possible to constantly update and store electrocardiogram-related parameters for a predetermined maximum time, and doctors can record electrocardiogram waveforms when an abnormality occurs in the examination room. There is a need for a portable electrocardiograph that can provide instant information.

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

[0013]

[Means for Solving the Problems] A portable electrocardiograph according to the present invention includes a means for temporarily storing electrocardiogram data obtained from a patient together with time information, and a means for temporarily storing electrocardiogram data obtained from a patient and determining whether the electrocardiogram data is abnormal or normal. means for determining, a plurality of counting means for individually counting the frequency of occurrence of abnormal electrocardiogram data for each fixed unit time and storing it together with time information; means for repeatedly updating and storing the frequency of occurrence of abnormal electrocardiogram data each time a period of time elapses; and means for reading and reproducing the frequency of occurrence of abnormal electrocardiogram data and the electrocardiogram waveform at the time of abnormality for each fixed unit time during measurement of electrocardiogram data. It is characterized by comprising means.

[0014]

[Operation] According to the portable electrocardiograph according to the present invention, the latest information is always ensured as the frequency of occurrence of abnormal electrocardiogram data for each fixed unit time. The latest frequency of occurrence and the electrocardiogram waveform at the time of abnormality can be reproduced and checked at any time.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a portable electrocardiograph according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical configuration of the main parts of a portable electrocardiograph.

In the figure, 2 is a sensor section (body surface electrode) that picks up an electrocardiogram signal by being attached to a patient, 4 is an amplification section (electrocardiogram amplifier) that amplifies the electrocardiogram signal obtained by the sensor section 2, and 6 is a sensor section (body surface electrode) that picks up electrocardiogram signals by being attached to the patient. is an A/C converter that converts amplified analog ECG signals into digital ECG data.
D conversion unit, 8 is a CPU in a microcomputer;
10 is a ROM that stores programs, 12 is a RAM as a working memory, 14 is a liquid crystal drive unit that is driven and controlled by the CPU 8, and 16 is a display device in which minute liquid crystal display elements are arranged in a matrix vertically and horizontally to display various data such as numerical values, graphs, etc.
a liquid crystal display (LCD) configured to display any waveform, 18 an external input section consisting of a group of various operation keys (including keys displayed on the liquid crystal display 16); 20;
is a warning device such as a buzzer.

The ROM 10 and RAM 12 are unitized as an IC card, and are detachable from the main body.

The RAM 12 has a storage area for temporarily storing electrocardiogram data obtained by the A/D converter 6 together with time information in a memory loop manner via the CPU 8. The CPU 8 has a function of reading electrocardiogram data from the RAM 12 according to a program stored in the ROM 10 and determining whether the data is a premature ventricular contraction (PVC). It has a function to store data as abnormal electrocardiogram data in the RAM 12 along with time information, a function to count the frequency of occurrence of PVC (premature ventricular contraction) every hour, and store the frequency of occurrence in the RAM 12 together with time information. are doing. Further, the CPU 8 has a function of reading data on the frequency of PVC occurrence from the RAM 12 and converting it into display data of a trend graph.

Next, the operation of the portable electrocardiograph of this embodiment will be explained based on the flowcharts shown in FIGS. 2 to 5.

When the power is turned on, control operations by the CPU 8 are started, and an initial screen as shown in FIG. 6(a) is displayed on the liquid crystal display section 16. The electrocardiogram signal picked up by the sensor section 2 is amplified by the amplification section 4, converted into digital electrocardiogram data En by the A/D conversion section 6, and inputted to the CPU 8. The CPU 8 performs the following control operations according to the program loaded from the ROM 10.

[0022] First, in step S1, the CPU 8 determines whether a measurement key (actually a key displayed on the liquid crystal display section 16) in the external input section 18 has been operated. When it is determined that the operation has been performed, step S2~
The routine of S29 is executed (details will be described later), and if not, it is determined in step S50 whether the recording/playback key in the external input section 18 (actually the key displayed on the liquid crystal display section 16) has been operated. However, when it is determined that the operation has been performed, steps S51, S19 to S28, and S5 are performed.
2 (details will be described later), and if not, return to step S1.

Generally, the measurement key is operated first. Therefore, the process proceeds to step S2, where all PVC occurrence count areas B0 to B24 in the RAM 12 are cleared, and the timer Tm and reproduction mode flag F are reset.

Next, in step S3, the A/D converter 6 is controlled, and the amplified electrocardiogram signal inputted by the A/D converter 6 is sampled at regular intervals (sampling frequency is 250 Hz), and A/D conversion is performed. The data is converted into digital electrocardiogram data En and taken into the CPU 8. and,
In step S4, the CPU 8 transfers the sampled electrocardiogram data En together with time information to the RAM 12 and temporarily stores it in a memory loop method.

Further, the process proceeds to step S5, where the electrocardiogram data En at that time is converted into waveform display data, and the display data is transferred to the liquid crystal drive unit 14.
By controlling the electrocardiogram waveform at that time, the liquid crystal display section 1
6, it is displayed in real time. Figure 6 shows an example of the display.
It is shown in (b).

[0026] Next, in step S6, the CPU 8
The electrocardiogram waveform is analyzed based on the electrocardiogram data read from M12 to search for the peak of the R wave that marks the end of one heartbeat. As shown in FIG. 7, the R wave peak is the part with the sharpest rise in the QRS complex, which is a characteristic point of the electrocardiogram waveform. As a method of searching for the R-wave apex, for example, a point that is larger than a predetermined threshold value VREF and is an inflection point is determined to be the R-wave apex. Then, a point a certain time T0 before the peak of the R wave is the starting point A of the heartbeat.
shall be.

In step S7, the RR interval value (Rn -Rn-
1) is calculated and stored in the RAM 12. Then, in step S8, R- calculated for the current heartbeat Wn
The previous heartbeat Wn- of the R interval value (Rn - Rn-1)
The R-R interval value calculated for 1 (Rn-1 −R
Calculate the rate of change αn from n-2).

Next, in step S9 of FIG. 3, the rate of change αn
The electrocardiogram data En at the current heartbeat Wn depends on whether or not
It is determined whether the data is abnormal electrocardiogram data as PVC (premature ventricular contraction).

When the rate of change αn is less than the predetermined value α0, the electrocardiogram data En at that time is normal and the process is skipped to step S15, but when it is greater than the predetermined value α0, the electrocardiogram data is abnormal, so the process is skipped to step S15. S1
0 and activates the alarm 20 to issue an alarm.

Next, in step S11, the CPU 8 increases the contents of the count area B0 of the current PVC occurrence frequency by +1.
Increment by Then, in step S12, it is determined whether the storage area for abnormal electrocardiogram data is full or not. After erasing the old abnormal electrocardiogram data, in step S14, the electrocardiogram data En at the current heartbeat Wn is RAed together with time information as abnormal electrocardiogram data An as PVC (premature ventricular contraction).
Store in M12.

Next, the process proceeds to step S15, where it is determined whether or not the timer Tm has counted up one hour.
If no time has passed, skip to step S18 in FIG. 4, but if one hour has passed, skip to step S1.
Proceed to step 6 to shift the PVC occurrence frequency every hour.

That is, the PVC occurrence frequency stored in the count area B23 for the PVC occurrence frequency 23 hours before now is shifted to the count area B24 for the PVC occurrence frequency 24 hours before the current time. B24←B
23), similarly, B23←B22, B22
←B21...B3 ←B2 , B2 ←B1 is shifted, and the PVCs stored in the count area B0 of the current PVC occurrence frequency are compared to the count area B1 of the PVC occurrence frequency one hour before now. Shift the frequency of occurrence.

[0033] From the above, hourly P for 24 hours
This means that the VC occurrence frequency has been updated. That is, the PVC occurrence frequency for the latest 24 hours is always stored. However, until 24 hours have passed from the start of measurement,
There is a PVC occurrence count area whose content is 0.

When the hourly updating of the PVC occurrence frequency is completed, in the next step S17, the contents of the count area B0 of the current PVC occurrence frequency are cleared and the timer Tm is reset.

During this time, the electrocardiogram waveform at the current heartbeat Wn is displayed on the liquid crystal display section 16, as shown in FIG. 6(b).

In the next step S18 shown in FIG.
It is determined whether the key (displayed in ) has been operated, and if it has not been operated, the process returns to step S3 in FIG. 2 and the above operations are repeated.

When the playback key is operated, step S
19, a reproduction content selection screen as shown in FIG. 6(c) is displayed on the liquid crystal display section 16. And step S2
0, S22, S24, and S26, determine whether the serious record playback key, PVC trend graph key, 24-hour summary key, or event record playback key is operated. (These keys are actually displayed on the liquid crystal display section 16), and step S is performed according to the operated key.
21, S23, S25, etc. are performed.

That is, when the critical record playback key is operated, in step S21, abnormal electrocardiogram data An indicating PVC (premature ventricular contraction) is read out from the RAM 12, and as shown in FIG. 6(d). The abnormal electrocardiogram waveform is displayed on the liquid crystal display section 16. The abnormal electrocardiogram waveform can be sent forward or backward using the arrow keys on the liquid crystal display section 16.

When the PVC trend graph key is operated, a trend graph of the hourly PVC occurrence frequency from the present to the past 24 hours is displayed in step S23 as shown in FIG.
The image is displayed on the liquid crystal display section 16 as shown in (e) of FIG.

Further, when the 24-hour summary key is operated, in step S25, a table of the PVC occurrence frequency for each hour from the present to the past 24 hours is displayed on the liquid crystal display section 16 as shown in FIG. 6(f). do. Note that a description of the display operation of the event recording/reproduction key operation will be omitted.

Next, in step S27 shown in FIG. 5, it is determined whether the power is turned off, and if the power remains on, the reproduction mode flag F is set to "1" in step S28.
Since it is not currently set, the process advances to step S29, and the external input unit 18
It is determined whether or not the cancel key has been operated, and unless it has been operated, the process returns to step S20 (FIG. 4), but when it has been operated, the process returns to step S3 (FIG. 2).

[0042] When the power is turned off, step S30
Proceeding to (FIG. 5), a memory backup of the RAM 12 is performed to retain the data accumulated up to that point. Then, all operations are completed.

As described above, during measurement, the current electrocardiogram waveform is displayed on the liquid crystal display section 16 in real time,
Abnormal electrocardiogram data indicating PVC (premature ventricular contraction) An
If there is, P for 24 hours in hourly increments.
The frequency of VC occurrence is counted, and the abnormal electrocardiogram data An is stored in the RAM 12, and the frequency of PVC occurrence is updated every hour. If the playback key is operated during the process, displays as shown in FIGS. 6(c) to 6(f) are displayed.

Regarding the frequency of PVC occurrence, data after 24 hours is deleted in the measurement mode and always replaced with new data. Further, regarding abnormal electrocardiogram data, when the memory becomes full, the oldest data is deleted and always replaced with new data. Therefore, as long as the device is in the measurement mode, it is possible to always keep the latest 24-hour PVC occurrence frequency and abnormal electrocardiogram data up to the storage area full.

When the power is turned on again, the initial screen shown in FIG. 6(a) is displayed, and the recording/playback key is operated, step S
50 (FIG. 2) is affirmative, the process proceeds to step S51, and the reproduction mode flag F is set to "1". Therefore, this time, the process immediately skips to step S19 (FIG. 4) and performs the same operation as described above. In this case, step S2
8 (FIG. 5) becomes affirmative, and the process proceeds to step S52. In step S52, it is determined whether or not the cancel key in the external input unit 18 has been operated, and unless it has been operated, the process returns to step S20 (FIG. 4), but when it has been operated, the process returns to step S1 (FIG. 2).

[0046] As a means for reproducing electrocardiogram data,
In addition to displaying on a display such as the liquid crystal display unit 16, it may also be printed out using a printer.

[0047]

As described above, according to the present invention, the latest information as the frequency of occurrence of abnormal electrocardiogram data for each fixed unit time and the electrocardiogram waveform at the time of abnormality can be reproduced and confirmed at any time in the examination room or hospital room. It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of a portable electrocardiograph according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation according to the embodiment.

FIG. 3 is a flowchart for explaining the operation according to the embodiment.

FIG. 4 is a flowchart for explaining the operation according to the embodiment.

FIG. 5 is a flowchart for explaining the operation according to the embodiment.

FIG. 6 is an illustrative diagram of various display states according to the embodiment.

FIG. 7 is an explanatory diagram of how to calculate the RR interval value according to the embodiment.

FIG. 8 is a schematic configuration diagram of a Holter electrocardiograph according to a conventional example.

FIG. 9 is a schematic configuration diagram of an analysis device according to a conventional example.

[Explanation of symbols]

2　　　　　Sensor part 4 Amplification section 6 A/D conversion section 8 CPU 10 ROM 12 RAM 14 Liquid crystal drive unit 16 Liquid crystal display 18 External input section 20 Alarm

Claims (1)

[Claims] Claim 1: Means for temporarily storing electrocardiogram data obtained from a patient together with time information, means for determining whether the electrocardiogram data is abnormal or normal, and generation of abnormal electrocardiogram data every fixed unit time. a plurality of counting means for individually counting frequencies and storing them together with time information; a means for storing the abnormal electrocardiogram data; and a plurality of counting means for individually counting frequencies and storing the abnormal electrocardiogram data; A portable electrocardiograph characterized by comprising means for updating and storing the electrocardiogram data, and means for reading and reproducing the frequency of occurrence of abnormal electrocardiogram data and the electrocardiogram waveform at abnormal times during the measurement of electrocardiogram data. .