JPH10165385A - Portable electrocardiograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight to allow the installation for a long time and the collection of effective data by stopping the rewriting at a point of time when a fixed ratio of a memory is renewed when a switch for controlling the writing operation to a memory is operated, and recording the electrocardiographic information before and after pressing the switch to the memory. SOLUTION: A switch 3 is provided on the upper surface of a body 1 so as to be optionally operable by a wearing person, and the operation of the whole device is started by the ON of the switch 3 to start the recording of data of electrocardiographic signals into a memory 10. When the memory 10 is filled up, the older data are successively erased and renewed to new data. When the switch 3 is OFF, a controller 11 stops the renewing of the memory 10 after a fixed time, and cuts the power source of the whole device. The data for the total time of a fixed time before the switch 3 is OFF and a fixed time after OFF are recorded in the memory 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable electrocardiogram information recording apparatus used in the medical field of heart disease and the like, and in particular, is capable of recording electrocardiographic information even in the case of a very rarely occurring heart attack. It relates to a portable electrocardiograph.

[0002]

2. Description of the Related Art Conventionally, a holter electrocardiograph which is worn on a subject and records electrocardiogram data employs a method of recording an electrocardiographic signal as an analog signal or converting it into a digital signal. A magnetic tape is used as a recording medium. The recording time is also 24 hours.

[0003]

The conventional Holter electrocardiograph using a magnetic tape has a relatively large device, is heavy, and has poor portability. As a result, the user is uncomfortable. The recording time is 24 hours (or 48 hours)
If the seizure does not occur during that time, the recorded data is wasted. The next test I had to go to the hospital and have an electrocardiograph on was done.

[0004] Therefore, patients who have a low frequency of heart attacks have little chance of receiving a diagnosis, and the treatment tends to be delayed. Therefore, an electrocardiograph that enables long-term collection and recording of electrocardiographic signals until a seizure occurs has been desired, but in order to avoid inconvenience to the user even when worn on the body for a long time. Must be small and lightweight. In addition, when used for a long period of time, battery consumption naturally becomes a problem. That is, 1
There is a demand for an electrocardiograph that can record electrocardiogram data on patients with subjective symptoms such as infrequent, but intense pain once every two months.

An object of the present invention is to solve these problems of the prior art and reduce the size and weight of the electrocardiograph so that the user does not hinder daily life and does not cause discomfort. An object of the present invention is to provide a portable electrocardiograph that can be worn for a period of time and enables effective collection of electrocardiographic data.

[0006]

According to a first aspect of the present invention, there is provided a portable electrocardiograph for digitally recording an electrocardiographic signal, which is an electrical signal from the heart, in a built-in memory. A switch for controlling a write operation to the memory, recording an electrocardiographic signal while sequentially updating the memory in the memory, and when the switch is operated, stops rewriting when a certain percentage of the memory is updated. Then, the electrocardiographic information before and after the switch is pressed is recorded in the memory.

As a second invention, a portable electrocardiograph is provided with a low frequency generating means and a voltage level detecting circuit of a power supply battery, and when the battery voltage falls below a predetermined level, the output of the low frequency generating means is output. Was passed through an electrocardiographic sensor, and the electrocardiographic sensor was used as an electrode of the low frequency generating means, and stimulation of the muscle was given to notify the battery replacement.

In the first invention, a flash memory of about 2 megabytes is used as a recording medium instead of a magnetic tape, and a power supply is a dry battery of about 500 milliamp hours. Thus, the entire apparatus can be reduced in size and weight, and can be easily mounted. By allowing the patient to wear the electrocardiograph anytime and anywhere during the period desired by the patient, and by providing a switch (hereinafter referred to as a switch or trigger) for controlling the recording operation, which is a feature of the present invention, the heartbeat can be freely determined by the user. The collection and recording of electronic information has been made possible. That is, the information of the electrocardiographic signal is
It is always rewritten and recorded in the memory, and new information is always recorded in the memory. This allows the user (= patient) to wear it for a long time until a seizure occurs,
By pressing the switch for recording control when an attack occurs, an attack, that is, an electrocardiogram before and after the trigger is obtained. As an example, one hour of electrocardiographic information can be recorded in the built-in flash memory. If the data rewriting operation to the memory is stopped 40 minutes after the trigger is pressed, the data for 20 minutes before the trigger is also recorded. In this way, it is possible to record electrocardiographic information that could not be caught stochastically with the conventional 24-hour Holter monitor.

In the second invention, the battery life is notified. In such a portable electrocardiograph, since a recording operation is always performed, a small dry battery does not last much.
For a device with a current consumption of 2 mA, the calculation is only about 10 days. Therefore, when the remaining battery power becomes low, it is necessary to replace the battery. As a warning of battery replacement, in the present invention, even if the current consumption is small, the user (= patient)
Low-frequency currents that could stimulate the muscles of the children. In addition, if the low-frequency current to be stimulated is also used by an electrocardiographic sensor that takes out electrocardiographic information in close contact with the skin of the user (= patient), a new electrode is not required. By replacing the battery in this way, it is possible to monitor long-term electrocardiographic information with peace of mind, and when a cardiac abnormality is recognized, electrocardiographic information before and after that can be recorded.

[0010]

FIG. 1 is a schematic explanatory view showing an embodiment of a portable electrocardiograph according to the present invention. FIG. 2 is a block diagram of the electrocardiograph of FIG. FIG. 3 shows the operation timing in this embodiment.

The number of electrocardiographic sensors is not particularly limited.
In addition, since the apparatus main body can be made compact, the bottom surface of the main body is used as one of the electrocardiographic sensors. As a result, the number of sensors pulled out from the main body can be reduced by one. In the figure, the electrocardiographic sensors 5d and 5e are the stimulation electrodes of the present invention.

In FIG. 1, reference numeral 1 denotes a main body, and its bottom surface also serves as one of the electrocardiographic sensors. Reference numeral 2 denotes a battery storage unit, and reference numeral 3 denotes a switch according to the present invention, which controls a power supply and a recording operation of the entire apparatus. The switch 3 is disposed on the upper surface of the main body 1,
ON from the top of a shirt etc. even when the main body 1 is attached to the body
/ OFF operation is possible. Reference numeral 4 denotes an interface connector for connecting to an external analyzer or a data communication adapter. Reference numeral 5a denotes a bottom surface of the main body and an electrocardiographic sensor, which is sticky like the other sensors 5b to 5e. Reference numerals 5b to 5e denote other electrocardiographic sensors attached to parts other than the main body, and one of 5a to 5e is an unrelated sensor for canceling noise. Among them, 5d and 5e are used as stimulating electrodes for battery warning to notify battery replacement.

FIG. 2 is a circuit block diagram of the electrocardiograph according to the present embodiment.
The electrocardiographic signals from a to 5d are respectively supplied to the differential amplifier circuits 6a
, And passes through the sample and hold circuits 7a to 7d.
The signal from d is fetched into one by time division, digitized by the A / D converter 9, and recorded in the built-in memory 10. Reference numeral 11 denotes a controller that performs power control, memory control, system control, and the like, and also includes a low frequency generation circuit. Reference numeral 12 denotes a battery check circuit. The switch 3 is provided on the upper surface of the main body 1 and can be arbitrarily operated by the wearer. When the switch 3 is turned on, the entire apparatus starts operating, and starts recording the data of the electrocardiographic signals in the memory 10. When the memory becomes full, the oldest data is sequentially deleted and updated with new data.

When the switch 3 is turned off, the controller 11 stops updating the memory 10 after time t2, and turns off the power of the entire apparatus. The switch 3 is in the memory 10
Data for a total of T time, that is, t1 hour before FF and t2 hour after OFF, is recorded.

Reference numeral 13 denotes a power supply battery, 14 denotes a low-frequency amplifier according to the present invention, and sensors 5d and 5 serving as two stimulation electrodes.
There are two outputs to send current to e. A changeover switch 15 switches between when the sensors 5d and 5e work as an electrocardiographic sensor and when they work as low-frequency stimulation electrodes. This control signal is output from the controller 11 in response to a signal from the battery check circuit 12.

FIG. 3 shows the relationship among the switch 3, the circuit power supply, and the contents of the memory. The power is turned off t2 hours after the switch 3 is turned off, and data for the time t1 before the switch 3 is turned off remains in the memory 10.

Next, an example of use of the electrocardiograph will be described. The user (examinee = patient) turns on the switch 3 and wears the electrocardiograph by himself. The main body and the electrocardiographic sensor are stuck to predetermined positions with an adhesive bandage or the like so as not to easily come off. When the mounting is completed, the switch 3 is turned on. Thereby, the data of the electrocardiographic information starts to be written into the built-in nonvolatile memory 10. If upset, oppression,
When an attack such as arrhythmia or severe pain occurs, the subject presses the switch 3 by himself / herself, and stops the operation of writing the data of the electrocardiographic signal to the memory 10 after a predetermined time (t2). In the memory 10, data for a time before the switch 3 is pressed (t1) and data for a time after the switch 3 is pressed (t2) are recorded. And immediately went to a medical institution,
Data is taken out from the connector 4 of the device body 1 and analyzed and
You can get a diagnosis. Also, by connecting to a portable terminal or the like, the electrocardiographic data can be transmitted to a computer server in a medical institution or an emergency medical center.

When the battery 13 is exhausted and the battery voltage falls below a predetermined voltage, a signal is sent from the battery check circuit 12 to the controller 11, and the switching switch 15
To b, a low-frequency stimulation current flows to the electrocardiographic sensors 5d and 5e. The user feels the same muscle stimulation as the low frequency treatment device. This stimulus issues a battery replacement warning. At that time, after turning off the switch 3,
Open the battery compartment 2 to replace the battery.

If the user feels inconvenient in daily life after wearing for a long period of time, for example, when taking a bath, the user can easily remove the apparatus body 1 by himself. At the time of storage, the switch 3 is turned off.

Next, an estimate of the recordable time when the memory capacity is assumed to be 2 megabytes will be described. Assuming that the number of electrocardiographic sensors excluding the unrelated sensor is 4, the resolution is 8 bits, and the sampling frequency per sensor is 100 Hz, the data for one second is 4 × 8 × 100 = 3200 (bits). Therefore 2
In M bytes, it takes 5,000 seconds, that is, slightly over 1 hour and 20 minutes. This corresponds to the memory time T in FIG. Since the seizure is a long time of about 30 minutes from a few minutes, electrocardiographic information before and after the seizure is sufficiently recorded.

The recorded electrocardiographic data is transmitted to the connector 4
Through an external analyzer / inspection device or portable terminal device not shown in the figure. At this time, the clock frequency can be set to several MHz to perform high-speed transfer.

[0022]

As described above, according to the configuration and method of the present invention, it is possible to reduce the size and weight of the holter electrocardiograph by far, and does not feel inconvenience even when the holter is used for a long time. This makes it possible to miss an opportunity to record a seizure with only the 24-hour recording so far, and to provide a very effective examination / diagnosis device for patients who have not been effectively treated. The patient can wear this electrocardiograph on the body forever until a seizure occurs,
It becomes possible to record an electrocardiographic waveform when an attack occurs.

Also, when the battery is exhausted, it can be known by comfortable muscle stimulation like a low-frequency therapeutic device, and long-term monitoring of the electrocardiographic signal becomes possible by replacing the battery.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of a portable electrocardiograph of the present invention.

FIG. 2 is a block diagram of the electrocardiograph of FIG. 1;

FIG. 3 is a timing chart showing operation timing in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrocardiograph main body 2 Battery storage part 3 Switch 4 Interface connector 5a-5e Electrocardiographic sensor 6a-6b Differential amplifier 7a-7d Sample hold circuit 8 Multiplexer 9 A / D converter 10 Semiconductor memory 11 Controller 12 Battery check circuit 13 Battery 14 Low frequency amplifier 15 Switch

Claims (2)

[Claims] 1. A portable electrocardiograph for digitally recording an electrocardiographic signal, which is an electrical signal from a heart, in a built-in memory, comprising a switch for controlling a writing operation to the memory, wherein the electrocardiographic signal is stored in the memory. When the switch is operated, the rewriting is stopped when a certain percentage of the memory is updated, and the electrocardiogram information before and after the switch is pressed is recorded in the memory. Characteristic portable electrocardiograph. 2. A portable electrocardiograph comprising a low frequency generating means and a voltage level detecting circuit for a power supply battery, wherein when the battery voltage falls below a predetermined level, the output of the low frequency generating means is detected by an electrocardiograph. A portable electrocardiograph characterized in that an electrocardiographic sensor is used as an electrode of a low-frequency generating means by flowing to a sensor and a stimulus is given to a muscle to notify a battery replacement.