JPH061689Y2 - Freeze type ECG monitor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is to store an electrocardiogram signal induced in an electrode in a memory by attaching the electrode integrally to a substrate and applying it to the chest by hand to display a waveform. The present invention relates to a freeze type electrocardiogram monitor adapted to freeze.

[Conventional technology]

In this type of electrocardiogram monitor, in order to automatically perform the operation without separately preparing a manual operation switch for suspending the memory update and freeze-displaying the immediately previous stored contents, according to the actual opening Sho 63-109104, Detecting an increase in the input signal level of the amplifier circuit due to the removal of the electrodes from the chest, interrupting the update of the memory contents in response to the detection signal, and displaying the immediately preceding memory contents. Is proposed.

[Problems to be solved by the device]

This freezes the electrocardiogram signal waveform in conjunction with removing the electrode from the chest at the end of the measurement.
In the method of detecting an increase in the input signal level of the above-mentioned amplifier circuit, even a slight change in the contact state of the electrode is detected and the input signal level is immediately frozen, and the electrocardiogram when the electrode mounting state is unstable There was a problem that it was easy to freeze the signal waveform.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a freeze-type electrocardiogram monitor that freezes an appropriate waveform in a timely manner.

[Means for solving problems]

In order to achieve this object, the present invention amplifies an electrocardiogram signal induced by applying an electrode integrally attached to a substrate to the chest with a hand by an amplification circuit, digitizes the amplified signal, and freezes the memory. In a freeze-type electrocardiographic monitor adapted to write to the circuit while sequentially writing and to display a real-time or electrocardiographic waveform stored in a memory circuit on a display device, in order to achieve the above-mentioned purpose, connect to an electrode The amplifier circuit consists of a CR oscillator circuit that oscillates with an increase in input impedance when the electrodes are removed from the chest, and performs an amplifying action when the electrodes are attached to the chest, and detects the oscillation signal of this CR oscillator circuit. Then, the oscillation detection signal is output to suspend the writing of the freeze memory circuit while the oscillation signal is being detected, and An oscillation signal detecting means for freeze display the stored contents of the memory circuit in the display device in place of the view,
It is characterized in that it is provided with a timer means which is reset by the oscillation detection signal and, when a predetermined time elapses, displays on the display device in real time and writes to the memory circuit.

[Action]

The CR oscillating circuit amplifies the induced electrocardiogram signal without oscillating because the input impedance of the CR oscillating circuit becomes small when the electrodes are worn on the chest. As a result, when the timer means detects that the oscillation signal detection means does not generate the oscillation detection signal for a predetermined time or more, the display device is caused to perform real-time display and writing to the memory.

When the electrode is removed from the chest, the CR oscillation circuit oscillates, and the oscillation signal detection means outputs the oscillation detection signal to reset the timer means and interrupt the writing of the freeze memory circuit while the oscillation signal is being detected, and at the same time real time. Instead of the display of, the stored contents of the memory circuit are freeze-displayed on the display device.

〔Example〕

FIG. 1 is a diagram showing a circuit configuration of a portable freeze-type electrocardiogram monitor 1 (see FIG. 2) according to an embodiment of the present invention. In these figures, an indifferent electrode 2 and a pair of related electrodes 2a and 2b are arranged on one surface of the electrocardiogram monitor 1 which functions as an electrode substrate. Reference numeral 3 is a pre-stage amplifier circuit for amplifying an electrocardiogram signal induced in the pair of electrodes 2a and 2b. This amplifier circuit has R1, R2, C1, C
By providing a feedback circuit composed of two, a CR that performs an amplification action when the contact electrode 2a is worn on the chest
It constitutes an oscillator circuit. That is, assuming that the resistance values of R1 and R2 are R ₁ and R ₂ , the capacitances of C1 and C2 are C ₁ and C _2, and the human body impedance when the electrodes are attached is Z _B ,
Under the condition of R ₁ · C ₁ >> R ₂ · C ₂ , R ₁ >> Z _B , the oscillation frequency f = 1 / (2π · C ₁ · R ₁ ) gives, for example, about 1
Pulse oscillates at 00Hz, R ₁ with electrodes 2 and 2a attached
≉Z _B , oscillation stops, and the circuit functions as an amplification circuit.

Reference numeral 4 is a main amplifier circuit for further amplifying the amplified signal, and 5 is an A / D converter for digitizing the amplified signal. 6 is a liquid crystal display attached to the opposite surface of the electrocardiogram monitor 1 to display an electrocardiogram waveform for about 5 seconds, and 7 is a digitized electrocardiogram signal which is sequentially updated and stored for one screen. It is a memory circuit.

Reference numeral 10 is an oscillation signal detecting means for detecting that the mounting surface of the electrocardiogram monitor 1, that is, the electrodes 2 and 2a oscillate out of the chest. The oscillation signal detecting means 10 detects the pulse generation of the amplitude corresponding to the saturation level and oscillates at the H level. By outputting the detection signal, writing in the freeze memory circuit 7 is interrupted, and the stored contents are replaced with the liquid crystal display 6 instead of the real-time display.
To freeze display. Reference numeral 11 is a timer means, which is reset by the above-mentioned oscillation detection signal, and when the predetermined time, that is, the time when it can be determined that the electrodes 2 to 2b are securely attached has passed, the electrocardiogram signal is directly displayed on the liquid crystal display 6. , The memory circuit 7 is updated while writing is performed.

The operation of the electrocardiogram monitor 1 configured in this way is as follows.

When the electrode side of the electrocardiogram monitor 1 is applied to the chest, the amplification circuit 3
Oscillates due to its low input impedance, so that the output signal of the oscillating signal detecting means 10 becomes L level, and when the timer means 11 starts measuring time and a predetermined time has elapsed without being reset, the gate electrodes 2, 2b The electrocardiogram signal which is induced between and amplified by the amplifier circuits 3 and 4 and digitized by the A / D converter 5 is sequentially stored in the memory circuit 7.
And the waveform is displayed on the liquid crystal display 6 in real time.

When the electrocardiogram monitor 1 is removed from the chest while the desired electrocardiogram signal is displayed, the amplifier circuit 3 oscillates when the oscillation condition is satisfied, and the output signal level of the oscillation signal detecting means 10 becomes H level. , The timer means 11 is reset and the update of the memory circuit 7 is interrupted, and instead of the real-time electrocardiographic signal, the electrocardiographic waveform data for one stroke stored in the memory circuit 7 is repeatedly displayed to perform freeze display.

FIG. 3 shows an embodiment using a microcomputer, and CPU 25, ROM 26, RAM 27 for storing freeze data for 4 seconds, clock 28, etc. so as to configure the oscillation signal detecting means, timer means and memory circuit described above. And a first through I / O port 22
A / D converter 5, main amplifier circuit 4 and indicator 16 in the figure
Connected to.

That is, the CPU 25 takes in an electrocardiogram signal from the A / D converter 5 shown in FIG. 1, creates display data, sends it to the display 16, and writes it in the RAM 27. CPU2
5m 40m while further processing the data of the electrocardiogram signal
If an oscillation signal is not input to the I / O port 22 during the interval at intervals of s, if the oscillation signal is not detected, the non-detection state is timed and continues for 0.5 seconds or more.
7 is written, and display data is sent to the display 16. On the other hand, every time the oscillation signal is detected, the writing to the RAM 27 is interrupted for at least 40 ms, and the RAM 27 is
Data is sent as real-time display data.

The operation will be described with reference to the flowchart of FIG. When the measurement starts, the electrode attachment status is searched at 40 ms intervals, and if no oscillation signal occurs for 0.5 seconds or longer, it is judged as a normal measurement status and the electrocardiogram signal waveform is monitored.
One display fraction is stored while being sequentially updated to AM27. If the electrocardiogram monitor is removed or if the electrode attachment state is not perfect, the oscillation signal is detected and writing to the RAM 27 is immediately interrupted, and the electrocardiogram signal for the past 4 seconds that does not include the oscillation signal is freeze-displayed.

The present invention can also be applied to an electrocardiogram monitor in which electrodes are attached to a substrate separate from the display unit.

[Effect of device]

As described above, according to the present invention, since the electrode detachment for the automatic freeze is detected by the presence or absence of the oscillation of the amplifier circuit, it can be detected more reliably than the simple level change detection, and the malfunction of the automatic freeze can be reduced. In addition, writing to the memory circuit
Since it is performed not only during oscillation but also when oscillation does not occur for a predetermined time or longer, an improper electrocardiographic waveform is prevented from being freeze-displayed before and after oscillation or when the electrode attachment is unstable. Similarly, since the real-time display is not performed for the predetermined time after the oscillation, the oscillation signal or the inappropriate ECG waveform is not displayed.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of a portable electrocardiographic monitor according to an embodiment of the present invention, FIG. 2 is a perspective view of the portable electrocardiographic monitor, and FIG. 3 is a configuration of an electrocardiographic monitor according to another embodiment of the present invention. And FIG. 4 are flow charts for explaining the operation of the electrocardiogram monitor. 1 ... Electrocardiogram monitor, 2 ... Indifferent electrodes, 2a, 2b ... Custom electrodes, 6 ... Liquid crystal display.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location 8119-4C A61B 5/04 310 H

Claims (1)

[Scope of utility model registration request] 1. An electrocardiogram signal induced by applying an electrode integrally attached to a substrate to a chest by hand is amplified by an amplifier circuit, and the amplified signal is digitized and sequentially updated in a freeze memory circuit for writing. In addition, the freeze-type ECG monitor that displays the ECG waveform in real time or stored in the memory circuit on the display device increases the input impedance when the amplification circuit connected to the electrode is removed from the chest. The oscillation signal is generated by virtue of a CR oscillation circuit that oscillates with the electrode and performs an amplification action when the electrode is worn on the chest, and outputs the oscillation detection signal by detecting the oscillation signal of the CR oscillation circuit. During the detection of, the writing of the freeze memory circuit is interrupted, and the contents stored in the memory circuit are replaced with real-time display. An oscillation signal detecting means for displaying a freeze on the display device; and a timer means for resetting by the oscillation detection signal and, when a predetermined time elapses, performing a real-time display on the display device and writing to the memory circuit. An electrocardiogram monitor characterized by.