JPS595957B2 - pacemaker pulse off - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone transmission system that accurately transmits electrocardiographic signals including base maker pulses.

As a technology for monitoring the condition of patients living in remote locations from medical facilities staffed by doctors skilled in interpreting electrocardiograms and managing implantable base manufacturers, electrocardiogram signals are converted into acoustic signals and connected to regular telephone lines. to the medical facility via
A system has been developed that allows a specialist to quickly make an accurate judgment. The problem with transmitting electrocardiographic signals containing base maker pulses using such a system is that the frequency band of base maker pulses is several hundred H2, and the frequency band of electrocardiographic signals is at most several hundred H2. In addition to being significantly different from 100 H2, it is also possible to
So-called acoustic couplers, which generate modulated acoustic signals,
The frequency band that can be transmitted with one center frequency is 150H2
Because of this, steep base maker pulses with frequency components of several hundred H2 or more are buried in the simultaneously transmitted electrocardiographic signals unless they have a very large peak value, and the receiving side It was not possible to measure the spacing accurately. As a telephone transmission system to improve these shortcomings, a so-called two-channel system has been proposed in which the electrocardiographic signal and the base maker pulse are transmitted via an acoustic coupler that converts the electrocardiographic signal and the base maker pulse into acoustic signals that are FM modulated at different center frequencies. There is.

However, in this two-channel system, the waveform is distorted due to interference between the channels, which often makes it difficult to make an accurate diagnosis. The present invention completely eliminates such drawbacks and provides a new telephone transmission system for accurately transmitting base maker pulses and electrocardiographic signals in one channel.

An embodiment of the present invention will be described in detail below with reference to the drawings. 1st
The figure is a block diagram showing the configuration of the present invention.

In the figure, 1 is a patient wearing an implantable base maker, and is about to undergo a determination of the battery life of the base maker and an electrocardiogram diagnosis. 2a and 2b are biological electrodes that are pasted on the chest wall of the patient 1 to induce electrocardiographic signals including base maker pulses, and 3 is an electrocardiograph for amplifying the induced electrocardiographic signals. be.

Further, 4 is a low-pass filter for removing noise components of, for example, 500H2 or more from the output of the electrocardiograph 3, and 5 is a filter circuit that passes, for example, a low-pass filter that passes signals of 100Hz or less, which is the main frequency band of the electrocardiogram signal. It is composed of a filter 6 and a bypass filter 7 that passes signals of 100 Hz or higher indicating pacemaker pulses.

8 is a conversion circuit that outputs 1 from the bypass filter 7.
It is used to convert pacemaker pulses limited to frequency components from 00Hz to 500Hz into a sine wave lasting approximately 50ms at 106Hz, and specifically, the output of a monostable multivibrator triggered by pacemaker pulses is generated. It is composed of an oscillator that generates sine wave oscillation at 106 Hz while the device is in use.

9 is an addition circuit that adds the 106 Hz sine wave signal that is the output of the conversion circuit 8 and the electrocardiographic signal that is the output of the low-pass filter 6; 10 is an addition circuit that adds the output of the addition circuit 9 to a center frequency of 1700 Hz, for example; Deviation frequency ±250H
A transmitting acoustic coupler that converts into an FM modulated acoustic signal of about z is shown.

Reference numeral 11 designates an ordinary telephone set, the transmitter of which is placed in close contact with the acoustic coupler 10, for transmitting the above-mentioned acoustic signals to the medical facility via the telephone line 12.
The operation of one embodiment of the present invention constructed in this manner will be described below with reference to the signal waveforms shown in FIG. Figure 2A
is the output waveform of the low-pass filter 4, and shows an electrocardiographic signal including the pacemaker pulse x from which noise components have been removed. However, as described above, such a signal is separated into the original electrocardiographic signal and the pacemaker pulse by the low-pass filter 6 and bypass filter 7 included in the filter circuit 5, using the highest value of the main frequency band of the electrocardiographic signal as the separation frequency. The separated pacemaker pulse is applied as a trigger pulse to the conversion circuit 8 at the next stage, and is converted into a sine wave y as shown in FIG. 2B. The frequency of the sine wave generated in the conversion circuit 8 is equal to or higher than the highest value of the main frequency band in which electrocardiographic signals can be transmitted without distortion, and is in the frequency band in which the FM modulated acoustic coupler can transmit at one center frequency (this embodiment In order to facilitate the work of reproducing the timing of pacemaker pulses, it is designed to start oscillating at a phase angle of 00 and last for several waves. 2C is an output waveform of the adder circuit 9, which is obtained by adding the converted waveform y of FIG. 2B in place of the pacemaker pulse X of FIG. 2A. Therefore, the transmitting acoustic coupler 10, the telephone set 11 and the telephone line 12
Although the transmission line, including the acoustic coupler, is limited to a narrow frequency band, the signal transmitted to the external medical facility via the It can also eliminate crosstalk that causes distortion. FIG. 3 is a block diagram showing the circuit configuration of a medical facility that receives electrocardiographic signals as described above.
In the figure, a telephone 13 is installed in the medical facility and is connected to the transmitting side via a telephone line 12. Further, the receiver of the telephone set 13 is placed in close contact with the reception acoustic coupler 14. When the acoustic coupler 14 receives an FM-modulated acoustic signal through the receiver, it demodulates an electrical signal having a waveform as shown in FIG. 2C. The demodulated electrical signal is passed through a band elimination filter 15 that removes only the 106 Hz frequency component of the converted signal, and only the electrocardiographic signal is separated and extracted, and then passed through an amplifier 16 to a recorder 17.
The patient's electrocardiogram is accurately drawn without distortion. The electrical signal demodulated by the reception acoustic coupler 14 is also supplied to a bandpass filter 18 .

The bandpass filter filters the converted sinusoidal signal y (second
It allows only the frequency component (106 Hz in this example) possessed by Figure B) to pass through. The bandpass filter 18
Since the output of is received as a sine wave signal of several wavelengths for one pacemaker pulse, the pacemaker pulse is Any number of wavelengths of the sine wave signal y (FIG. 2B) generated for each pulse is processed so as to generate a single pulse (output of a Schmitt circuit, which will be described later) at the same timing. That is, the output of the bandpass filter 18 is rectified by a double-wave rectifier circuit 19, and the rectified output is sequentially supplied to an integrating circuit 20 and integrated. When the integrated value of the integrating circuit 20 reaches a certain level, the aforementioned single pulse is generated from the Schmitt circuit 21, and is then supplied to the pulse interval measuring device 22 for determining the battery life of the implantable pacemaker. It is configured. Note that when the receiving device is configured to obtain a single pulse at a timing corresponding to the generation interval of pacemaker pulses using the integrating circuit 20 and the Schmitt circuit 21 as in this embodiment, the point at which the integration starts has an important meaning. , the sinusoidal signal which is the conversion signal of the pacemaker pulse is the first
As explained in the figure, phase angle 00)1. In order to make reproduction easy and accurate, it is preferable that the oscillation is started at the same time. Further, in the above embodiment, the case where the conversion signal of the pacemaker pulse generated in the conversion circuit 8 is a sine wave has been described in detail, but the waveform characteristics of the conversion signal are not limited to this embodiment.

As described above, the present invention provides the following advantages when transmitting electrocardiographic signals including pacemaker pulses over the telephone using an FM modulated acoustic coupler.
First, the electrocardiographic signal and the pacemaker pulse are separated by using the highest value of the main frequency band of the electrocardiographic signal as a separation frequency, and the separated pacemaker pulse is set at the highest value of the main frequency band of the electrocardiographic signal and above, and the acoustic coupler is at one center. This telephone transmission method converts the signal into a signal within a frequency band that can be transmitted at high frequencies, then adds it to the separated electrocardiogram signal and supplies it to the transmitting acoustic coupler. This makes it possible to accurately determine the timing at which pacemaker pulses occur. Not only can it be transmitted, but it also enables accurate telephone transmission without causing crosstalk that can distort electrocardiographic signals. As a result, even for patients with heart disease who use an implantable pacemaker and are forced to live far from a medical facility, they can request a specialist to diagnose the electrocardiogram and determine the battery life of the pacemaker. It is now possible to do so, and its utility value is enormous.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a signal waveform for explaining the operation of the embodiment shown in FIG. 1, and FIG. 1 is a block diagram illustrating one embodiment of an apparatus for receiving electrocardiographic signals including pacemaker pulses. 1... Patient, 2a, 2b... Bioelectrode, 3... Electrocardiograph, 4... Low pass filter for noise removal, 5...・・Filter circuit, 6・
...Low pass filter, 7 ... Bypass filter, 8 ... Conversion circuit, 9 ... Addition circuit, 10 ... Transmission acoustic coupler, 11...
...Telephone, 12...Telephone line, 13...
...Telephone, 14... Sound alarm coupler for reception,
15...Band elimination filter, 16.
...Amplifier, 17...Recorder, 18...
...Band pass filter, 19...Double wave rectifier circuit, 20...Integrator circuit, 21...
Schmitt circuit, 22...Pulse interval measuring device.

Claims (1)

[Claims] 1 In a telephone transmission system using an FM modulated acoustic coupler, a filter circuit that separates an inductive signal obtained from a bioelectrode into an electrocardiographic signal and a pacemaker pulse using the highest value of the main frequency band of the electrocardiographic signal as a separation frequency; If the pacemaker pulse separated by the filter circuit is equal to or higher than the highest value of the main frequency band of the electrocardiographic signal, and the acoustic coupler is
a conversion circuit for converting into a signal within a frequency band that can be transmitted at two center frequencies; A telephone transmission system for electrocardiographic signals including pacemaker pulses, characterized by comprising a circuit.