JPS5819229A - Portable long-time cardiograph recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel portable long-term electrocardiogram recording device.

Among the increasing number of adult diseases year by year, the heart! Among these diseases, the increase in ischemic heart disease is particularly problematic. As with any disease, early detection and diagnosis is the best treatment for ischemic heart disease. For early detection and diagnosis, long-term electrocardiogram recording is used. If the condition is at the unpleasant stage where abnormalities are detected in the electrocardiogram recorded in the hospital's clinic, the disease has progressed and is not at the stage of early detection. Therefore, early detection and diagnosis can only be achieved by recording electrocardiograms over a long period of time in daily life. For example, electrocardiograms are recorded continuously for long periods of time during exertion or throughout the night.

Then, this recorded content is played back at high speed, and cine arrhythmia is detected and analyzed from the recorded electrocardiogram. Based on this result, ischemic heart disease can be detected early.

Conventionally, long-term electrocardiogram recording devices for such purposes have been disclosed, for example, in Japanese Patent Publication No. 14386/1986.
It consists of an amplifier that is attached to the body and connected to nine electrodes, and an analog magnetic tape recording device as shown in FIG. 1 that records the signals from this amplifier. This long-term electrocardiographic E-recording device is much smaller than the regeneration analysis device, and can even be worn on one's body. However, since an analog magnetic tape recording device was used, there were four drawbacks. First, there was a limit to miniaturization. Second, because the tape drive mechanism had a mechanical structure, it lacked stability and durability. Third, analog magnetic tape is
The signal-to-noise ratio (8c) is not good. Fourthly, it is not easy to set an arbitrary playback speed vIfJ4 when reproducing data.

It is an object of the present invention to eliminate the above-mentioned drawbacks and provide a portable long-term electrocardiogram recording device that is wrinkle-free, lightweight, and has a good signal-to-noise ratio.

The present invention provides a portable long-term electrocardiogram recording device in which an electrocardiogram signal, which is an analog quantity, is converted into a digital quantity, and then the electrocardiogram signal in the digital quantity is subjected to signal processing and then stored in a memory section. be. Here, signal processing refers to data compression.
7 In this invention, in order to handle digital quantities, mechanical parts are removed from the entire device and it is computerized, so the electrocardiogram recording device is smaller in size than before, resulting in lower power consumption, stability, and Improves durability.

Furthermore, since data is compressed before being stored in the printing section, a large amount of data can be stored in a memory section with a small capacity.

Next, one example of the present invention will be explained based on the drawings.

As shown in Fig. 2, the main body of the portable long-term electrocardiogram recording device (21) in this embodiment is smaller than a cassette, and three electrocardiogram electrodes (22) are attached to it. . These three electrocardiogram electrodes (22) are attached to the patient's chest wall and detect the electromotive force associated with contraction of the heart muscle as an electrocardiogram signal. and three electrocardiogram electrodes (2
2) Fi, this electrocardiogram signal is transmitted to the electrocardiogram recording device (2)
1). The electrocardiogram recording device (21) is equipped with a recording-only cow conductor memory, which is equipped with electrocardiogram electrodes (21).
2) Record data based on electrical signals from. This data is reproduced at high speed in a reproduction analysis device installed at a hospital, etc., and is used for diagnosis and treatment by doctors.

In this embodiment, a magnetic bubble l memory is used as the memory section. Magnetic bubble memory is made into a small ili cassette, and the size is less than the size of a hand compared to a compact cassette, even if it is usually commercially available.

Now, as shown in Figure 3, the electrocardiogram recording device (21) is
Electrocardiogram amplifier (31) Programmable gain amplifier (31m), A/D converter (32) Microprocessing unit (hereinafter abbreviated as MPU) (33)
, read-only memory (hereinafter abbreviated as ROM) (34), and two-frame access memory (hereinafter abbreviated as RAM) (35).

Magnetic bubble memory (36), keyboard (3?),
Timer (38), input/output interface (hereinafter abbreviated as I10) (39), and electrocardiogram electrode (22a)
, (22b), and (22c). The control means referred to in the claims herein refers to the MPU (
It is a signal processing system centered on 33). Also, everything other than the electrocardiogram electrode (22) is packed into a size smaller than a cassette.

Three electrocardiogram electrodes (22b), (22C)
The signal from is fed to an electrocardiogram amplifier (31). The output of this electrocardiogram amplifier (31) is supplied to a programmable gain amplifier (31m). The output of this programmable gain amplifier (31M) is the A/D converter (32)
will be supplied to.

The output of the A/D converter (32) is supplied to a processing system centered on the MPU (33). The processing system centered around this MPU (33) is composed of MPU (33), ROM
(34), RAM (35), magnetic bubble memory (36) I keyboard (37), timer (3B)
.

Ilo (39).

The electrical signals detected by the electrocardiogram electrodes (22a), (22b), and (22c) are differentially detected by an electrocardiogram amplifier (31).

The electrocardiogram amplifier (31) is a differential amplifier 69, and the electrocardiogram electrode (22m) is based on the signal from the electrocardiogram electrode (22b).
) and (22C) are sent to the electrocardiogram amplifier (31
) to the negative and positive terminals. After all, the difference between these two signals is a signal corresponding to the movement of the heart. However, this signal often contains low frequency noise due to vibrations and body movements. Furthermore, since this signal is a biological signal, it is very weak. For this reason, it is desirable to amplify the signal, but since it includes low frequency noise, it is not preferable to amplify it unnecessarily. So, programmable gain amplifier (31m)
The gain is initially set, and feedback is applied during the data processing stage to adjust the gain.

The electrical signal amplified in this way is sent to an A/D converter (32
) is converted into digital data and transferred to the pass line of the MPU (33).

As shown in FIG. 4, the MPU (as) collects data from the A/D converter (32) to the user M (85). When a small amount of change data is stored in the RAM (35), noise is removed from the data and the process moves to **< process. Here, we will remove low frequency components below 15Hz due to body movements and vibrations, and 5Q
The main purpose is to eliminate the influence of Hz or @QHz power supplies.

After removing noise in this process, it is checked whether the gain in the programmable gain amplifier (31m) is appropriate and is 6x9. If appropriate, data collection will continue. However, if the gain setting is not appropriate, the gain at the programmable gain/amplifier (31m) is reset via Ilo (39). This ensures that the 8/N ratio of the signal is greater than a certain value, regardless of the amplitude of the electrocardiogram.

Up to this stage, noise has been removed from the electrocardiogram data and the 8/N ratio of the signal has been set to a desirable value. However, this data is extremely redundant and requires a considerable amount of storage capacity. Therefore, in this invention, this collected data is compressed to the minimum amount necessary for electrocardiogram arrhythmia analysis.

In this working example, AZTiCC (Ampl 1tude
-Zone -Time-j4poch Codi■
) is used as a data compression method. This AZ
TgC is a preprocessing prog.
ramfor real-time BCG rhy
thcn analysis (I 14);E,
Trans.

Biomed, gng, 15; PP128~
129, 1968), but here,
The main points will be explained using FIG.

The electrocardiogram waveform has many straight waveform parts, such as between ab, bc, and de in Figure 5. Conventionally, even such a portion was recognized as a dot according to the sampling rate. AI used in this example! In JTBC, for a straight line waveform part, only the starting point, end point, and period of data in this straight part are used as stored data. Between ab and bc in Fig. 5, the value of the difference in the amplitude direction and the time difference between the end point and the starting point are the same, and in a flat part like between do, the time difference between da and the average value in the amplitude direction are adopt. According to ZTBC, data is compressed to about 1/20th. Compressed 9 data are included in magnetic bubble memo 17
(36) K memorized. The above operations are repeated for a specified storage period, for example, 24 hours.

The amount of data to be stored is estimated as follows: Data recording amount - NxTxKxL where: N; number of samples per second T; recording time; data compression ratio L; data length. In this example, the sampling rate is 400Hz.
Since it is a byte, the storage capacity is less than 2M bytes.

Considering the current technological level, this is a magnetic (pull memory)
36), the storage capacity is not that large.

This magnetic bubble memory (36) contains the gain of the programmable gain amplifier (31m) in addition to electrocardiogram data.

The level of noise during data collection, information about the patient entered on the keyboard (37), recording time entered on the timer (38), etc. may also be recorded.

The patient, who is the person to be measured, performs one test while continuing his daily life for the designated recording time, and then submits the portable long-term electrocardiogram recording device (21) to a doctor or the like. This device (21) is connected to a reproduction analysis device (not shown) to reproduce recorded contents and perform diagnosis. At this time, since the recorded contents are digital data stored in the magnetic bubble memory (36), handling is very convenient. For example, it can be loaded into a playback analysis device at high speed, and any time can be recorded.
Random access for playback is very easy. That is, ``system responsiveness is significantly improved. Furthermore, the S/N ratio of the data is very good, and the amplification gain is always set appropriately, which is convenient for reproduction analysis.

Although one embodiment has been described in detail above, the present invention is not necessarily limited to this. For example, as illustrated in FIG.

(22b), (22c) and the electrocardiogram amplifier (31) may be cut together, a transmitting circuit (51) may be added to them, and only the companions may be attached to the human body. At this time, a receiving circuit (52) is added to the remaining recording device (21) and the electrocardiogram @
(2 buttons), (2 additions).

Connect with the (child) side via wireless. In this way, at 9 o'clock, the part of the ring 9 attached to the human body is approximately the same size as the conventional electrode, and the electrocardiogram electrode (22m), (22b),
Since there is no need for a lead wire to connect the electrocardiogram (22c) and the electrocardiogram waveform diagram (31), it becomes easier to use for the examiner.

Also, among the previous 4 examples, magnetic bubble memo! J (36) is a ★set type, and when performing playback analysis, remove this magnetic bubble memo 17 (36) from the main body, and then attach it to playback analysis device K.
It is also possible to make a wire.

No. aligl programmable gain amplifier (311)
A feedback amplifier circuit may also be used to vary the feedback impedance with the signal from Ilo (39).

As mentioned above, it is a matter of course that any modification is included in this version #4 as long as it does not deviate from mii' of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a perspective block diagram of a conventional portable electrocardiogram recording device, Fig. 4 is a flowchart of processing by the MPU (33) in the device, and Fig. 5 is an AZTF
FIG. 6 is a block diagram showing another embodiment. (22m>, (22b), (22c) --- ECG electrode (31 m) --- Programmable gain amplifier (32) --- A/D converter (33) --- ...MPU (36) ...Magnetic Bubble Memory Agent Patent Attorney Nori Chika Kensuke (and 1 other person) Fig. 1 Fig. 2 Fig. 4 Fig. 5 MutL c Fig. 6

Claims (1)

[Claims] (1) Portable long-term electrocardiogram recording characterized by comprising an electrocardiogram electrode for extracting an electrocardiogram signal, and a memory section for storing an analog signal from the electrocardiogram electrode as a digital signal and an output from the control means. Device.