RU2760990C2 - Method for determining heart work parameters and electronic device for its implementation - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: group of inventions relates to medical equipment, namely to a method and a wearable electronic device for determining heart work parameters. When implementing the method, a laser radiation stream is formed. The laser radiation stream includes radiation from the first pair of sources with different wavelengths. Each of sources is provided with a means of converting laser radiation reflected from a human body into electrical signals. Sources are made of diode. One of sources provides a wavelength from 540 nm to 550 nm, the second one - from 560 nm to 570 nm. At the same time, one of the mentioned sources provides longitudinal polarization, and the second one – transverse polarization. An additional laser radiation stream is formed of the second pair of diode laser radiation sources. The second pair of diode sources provides wavelengths from 520 nm to 528 nm and from 532 nm to 540 nm, respectively. Each source of the second pair is provided with a means of converting laser radiation into electrical signals. At the same time, one of the mentioned sources of the second pair provides longitudinal polarization, and the second one – transverse polarization. Tissues of a part of the human body are irradiated with streams. The radiation reflected from tissues is converted into electrical signals that carry information about heart work parameters. Based on electrical signals, biopotentials of the heart are determined. The wearable electronic device contains means of processing electrical signals carrying information about heart work parameters to implement the method.

EFFECT: due to laser radiation sources with different wavelengths and longitudinal and transverse polarization, the effect of external illumination is eliminated and, after mathematical processing, a better overall signal is obtained by adding two independent intensity curves of the reflected signal received from red blood cells with different spatial orientation.

4 cl, 5 dwg

Description

The technical field to which the invention relates

The invention relates to measuring equipment, in particular to wearable optoelectronic devices for measuring the parameters of the heart and can be used to obtain information about changes in the biopotentials of the human heart.

State of the art

A large number of means for measuring the biopotentials of the human heart is known from the prior art.

As the closest analogue, a well-known method for measuring the parameters of the heart was chosen, which consists in irradiating the tissues of the human body with laser radiation and converting the reflected flow into electrical signals (CN102894965, published on January 30, 2013). This known tool has insufficient sensitivity and accuracy in determining the biopotentials of the human heart and does not allow determining all five peaks of the cardiogram.

The essence of the invention

The problem solved by the invention: ensuring effective monitoring of the heart and measuring the parameters of a person's cardiac activity without disrupting the usual mode of life.

In the course of solving the problem, the following technical results are achieved: increasing the accuracy of determining the teeth, segments and intervals of a person's cardiogram for a long time in the course of his normal life; simultaneous recording of the cardiographic response from tissues with different sensitivity to the length and / or polarization of laser radiation; ensuring the possibility of integrating the device into information systems based on cloud storage of information.

The above technical results are achieved by the fact that a stream of laser radiation is formed, which includes radiation from at least two sources with different wavelengths, each said source is provided with a means of converting laser radiation into electrical signals, the said flow irradiates tissues of a part of the human body, transforms radiation reflected from tissues into electrical signals carrying information about the parameters of the heart, and on their basis, the biopotentials of the heart are determined.

The above technical results are also achieved by irradiating the tissues of the human body in the region of the right or left wrists with the said stream.

The above technical results are also achieved by the fact that the mentioned sources of laser radiation are diode, with one of them providing a wavelength from 540nm to 550nm, and the second from 560nm to 570nm, while one of the mentioned sources provides longitudinal polarization, and the second - transverse.

The above technical results are also achieved by the fact that the received electrical signals carrying information about the parameters of the heart are sent to a remote server, where they are correlated and summed.

The above technical results are also achieved by the fact that an additional laser radiation stream is generated from the second pair of diode laser sources with wavelengths from 520nm to 528nm and from 532nm to 540nm, respectively, each source of the second pair is provided with a means of converting laser radiation into electrical signals by said flows irradiate the tissues of a part of the human body, convert the radiation reflected from the tissues into electrical signals that carry information about the parameters of the heart, and on their basis, the biopotentials of the heart are determined.

The above technical results are also achieved in that the electronic device contains means for processing electrical signals carrying information about the parameters of the heart, to implement the method for determining the parameters of the heart in accordance with the present invention.

The above technical results are also achieved by the fact that the electronic device is made in the form of an integrated microcircuit.

The above technical results are also achieved by the fact that the said processing means are implemented in the form of software.

A distinctive feature of the present invention is the presence of at least two sources of laser radiation with different wavelengths, and each source is equipped with its own means of recording reflected radiation.

Short list of drawing figures

Figure 1 shows a general appearance of the device.

Figures 2 and 3 show the structure of the device with a different number of emitters.

Figure 4 shows a diagram of the interaction of the emitter and the reflected signal recorder.

Figure 5 shows the relationship of the reflected pulses with the elements of the cardiogram.

Implementation of the invention

Heart disease has come to the fore in recent decades as a cause of death and disability. In this regard, the task of developing new methods of diagnostics and monitoring of cardiac activity is becoming more and more urgent. Information about the parameters of cardiac activity is the basis for assessing the state of both individual organs and entire systems of human vital activity: the nervous system, adaptive capabilities, regulatory systems, etc. There are numerous diagnostic methods of the psychophysiological state based on the analysis of heart rate variability. At the same time, any technique based on the analysis of heart rate requires effective means of obtaining accurate primary measurement information about the parameters of cardiac activity.

One of the most common methods of obtaining primary measurement information is an electrocardiogram (ECG). As you know, an electrocardiogram (ECG) is a periodically repeating curve of the biopotentials of the heart, reflecting the course of the process of excitation of the heart, which arose in the sinus (sinus-atrial) node and spreads throughout the heart, recorded using an electrocardiograph. Its individual elements - teeth, segments and intervals - have special names:

- teeth P, Q, R, S, T

- intervals PQ, QRS, QT, RR;

- segments PQ, ST, TP.

They characterize the emergence and spread of excitation through the atria (P), interventricular septum (Q), gradual excitation of the ventricles (R), maximum excitation of the ventricles (S), repolarization of the ventricles (S) of the heart. The P wave reflects the process of depolarization of both atria, the QRS complex reflects the depolarization of both ventricles, and its duration is the total duration of this process. The ST segment and the G wave correspond to the phase of ventricular repolarization. The duration of the PQ interval is determined by the time it takes for excitation to pass through the atria. The duration of the QR-ST interval is the duration of the "electrical systole" of the heart; it may not correspond to the duration of the mechanical systole.

An ECG is obtained using an electrocardiograph, an apparatus designed to display the work of the heart, by recording a curve. It allows you to quickly record an ECG: it registers and measures the potential difference of the heart from the surface of the human body, using the application of electrodes. It can work both in manual and automatic modes. As a rule, the functionality of the device depends on the field of application, however, absolutely all devices must meet the requirement of high quality of the recorded electrocardiogram. High-quality ECG in any conditions can be obtained with special filters.

The electrocardiograph has become widespread in medicine due to its relatively simple device and uncomplicated methods of operation. It is safe and does not create discomfort for the patient.

However, the existing technologies for obtaining an ECG using an electrocardiograph are not very suitable for systems of long-term monitoring and observation of the patient's condition while maintaining the usual mode of life (mobility, mobility, etc.). ECG equipment is energy-consuming, massive, and it is difficult to ensure its reliable fixation on the patient's body while maintaining normal activity. The objective of the present invention is to provide a reliable and effective means for measuring and monitoring all parameters necessary for a complete analysis of cardiac activity (intensity of the P, Q, R, S, T waves). The information obtained with the help of this invention makes it possible to automate the calculation and analysis of the QRS complex, heart rate, Q-T, T-P, S-T intervals, etc.

The invention is based on the fact that the ability of red blood cells to reflect coherent radiation depends on a number of factors and primarily on the radiation wavelength and the phase of the heart. The intensity of the reflected waves is proportional to the number of red blood cells caught in the laser diode irradiation area. Thus, at each moment of time there is a correlation between the value of the biopotential of the heart and the intensity of the wave reflected from the patient's body and due to his condition.

In accordance with the invention, to determine the parameters of the heart, a laser radiation stream is formed, which includes radiation from at least two sources 4 and 5 with different wavelengths. Each said source 4 or 5 is provided with means 6 and 7 for converting laser radiation into electrical signals. The said flow irradiates tissues 21 of the human body, converts the radiation reflected from the tissues into electrical signals carrying information about the parameters of the heart, and on their basis, the biopotentials of the heart are determined (as shown in Fig. 4).

The method is carried out using the device shown in Figs. 1-3.

As shown in Fig. 1, a device for measuring the parameters of the heart function comprises a housing 1, for example, provided for convenience with a means of attachment 2 to the patient's body. The device can be equipped with a display 12 for displaying information about the parameters of the heart, as well as other information, such as time, date, body temperature, blood pressure, etc.

It is most advisable to install the device on the patient's wrist in the zone of maximum pulse manifestation. However, the present method allows measurements to be taken anywhere on the patient's body, in particular in the area of the shoulders, chest, and lower extremities. The attachment means 2 can be made, for example, in the form of a strap, as shown in FIG. 1. In this case, the device is installed on the patient's wrist in the form of a bracelet.

A power source 3 is installed inside the housing 1, at least two laser radiation sources 4 and 5. As shown in Fig. 2, each laser radiation source is equipped with means for converting laser radiation into an electrical signal carrying information about the parameters of the patient's heart (positions 6 and 7).

In the housing 1, there is also a memory unit 8 for recording information about the work of the heart and a unit 9 for transmitting information about the parameters of the work of the heart to external systems for processing and storing information, for example, to a cloud storage.

Preferably, the device may contain a pair of diode sources 4 and 5 of laser radiation with wavelengths from 540nm to 550nm and from 560nm to 570nm.

Molecular compounds of blood components (for example, hydroxyl groups in hemoglobin, etc.) have different values of natural frequencies and different ability to reflect optical radiation. In addition, blood components and tissue elements in the human body can occupy different spatial positions at different times. The basis of the invention lies in the simultaneous irradiation of the patient's body tissues with coherent radiation with two different wavelengths. In this case, radiation with one wavelength will receive the maximum response (in the form of a reflected wave) from one part of the molecular compounds and tissue elements, and radiation with a different wavelength will provide the maximum response from another part of the molecular compounds and elements. By adding the obtained values of the reflected signals, it is possible to obtain the most accurate correspondence with the actual value of the biopotential of the heart at each moment of time.

The device may additionally contain a second pair of diode sources 10 and 11 (Fig. 3) of laser radiation with wavelengths from 520nm to 528nm and from 532nm to 540nm. Accordingly, each additional source 10 and 11 of laser radiation is equipped with its own means of converting laser radiation into an electrical signal carrying information about the parameters of the patient's heart (positions 18 and 19).

An additional pair of emitters increases the measurement accuracy of the reflected signal by providing even greater coverage of the response of molecular compounds, increasing the dynamic range and increasing the width of the spectral analysis.

It is advisable that one source of laser radiation in a pair provides longitudinal polarization, and the second - transverse. This is because the red blood cells in the body are located differently in space. The greatest accuracy of the method is achieved when the polarization of the radiation coincides with the length of the blood cells. This makes it possible to exclude the influence of external illumination and obtain, after mathematical processing, a higher quality general signal by adding two independent curves of the intensity of the reflected signal received from bodies with different spatial orientation.

Block 9 for transmitting information about the parameters of the heart is made in the form of a wireless personal area network (WPAN) module, for example, the Bluetooth standard. As block 9, a wireless LAN module (for example, Wi-Fi) can be used.

The method used in the present invention makes it possible to obtain information with the required accuracy with constant radiation of sources 4, 5 and 10, 11. However, in a constant mode, the charge of the power supply is quickly consumed, despite the fact that for subsequent digitalization, the received reflected signal must be sampled, quantized and etc. In the case of using a constant mode of operation of the emitters, the device can be equipped with an analog-to-digital converter (for example, with a capacity of 24 bits and an operating range from 1V to 3V). This will allow the measurement information to be digitized and processed using the processor 17.

It is most expedient to immediately provide a pulsed mode of operation of the emitters and converters 6, 7. For this purpose, the device preferably contains a pulse generating unit 13, which provides pulsed laser radiation with a maximum frequency F up to 300 pulses per second. Pulse mode increases the device's life due to reduced power consumption, provides filtering of shadow measurement, and reduces the time of exposure to the patient's body tissues.

The pulse generating unit 13 can be made adaptive with the ability to change the pulse frequency from 30 to 300 pulses per second with a duration b from 1 μs to 33 ms (Fig. 5). This improves the accuracy of exposure and the timely response of the device to deviations from the norm.

The memory unit 8 is equipped with means for compressing the measurement information. To do this, you can use the Haar Wavelet filter and the Huffman coding algorithm, which will allow you to record large data with low power consumption for processing on remote servers.

The device can additionally be provided with a blood pressure measuring means 14 and a patient temperature measuring means 16. As a means 14, it is advisable to use low-power piezoelectric generators, which, as a result of vibrations from contact, generate a recording voltage from a pulse wave, and the registration of a pulse wave is also secondary.

The means for converting laser radiation into an electrical signal is expediently made in the form of a CCD element with an optical filter with an operating frequency range from 515 nm to 570 nm. Thus, unnecessary frequencies are removed, which may arise as a result of improper fit of the device or light exposure. This will, in turn, provide a more stable system response regardless of external noise and shadow current.

The device may contain means 15 for three-stage signal amplification with low, high and low pass filters connected in direct sequence. The optimal signal gain is from 10dBm to 18dBm.

Obviously, the device is based on electronic components containing means for processing electrical signals that carry information about the parameters of the heart. It is the electronic component that provides the implementation of the method in accordance with the invention.

An electronic device can be made in the form of an integrated microcircuit (hardware), in the form of software (software) or a combined software and hardware solution (firmware).

An electronic device for implementing the method can be built into any known medical devices (for example, systems for physiotherapy), thereby expanding their functionality.

The method is carried out as follows:

As shown in Fig. 5, the pulse generating unit 13 generates rectangular pulses of a given duration b from 1 μs to 1 ms with a frequency of F up to 300 Hz and a power of up to 20 mW and directs them to the laser radiation sources 4 and 5. The current value of the frequency and duration of the pulses can be selected based on the patient's condition. For example, at night, when there is no physical activity in order to conserve energy, the frequency and duration of the impulses can be minimal. During periods of high physical activity or when cardiac information is needed with particularly high accuracy (for example, in pre-infarction conditions), the frequency increases. Thus, an adaptive mechanism for the selection of radiation parameters is implemented depending on the conditions in which the patient is located and on the state of his health. The ability to regulate the radiation parameters allows you to select the optimal operating mode of the device for people with various diseases.

The laser beam falls on the tissues 21 of the patient's body and, having reflected from them (including from red blood cells) 20, the beam is captured by means (position 6) of converting laser radiation (photodetector) into an electrical signal, as shown in Fig. 4. Thus, the reflected radiation is registered, which carries information about the parameters of the heart.

The signal from the photodetector is amplified by a three-stage amplifier with subsequent filtering of the signal.

In a constant mode of operation of the emitters, the device is equipped with a processor 17 and the signal is preliminarily fed to an analog-to-digital converter, and then the digitized signal is fed to the processing unit.

To obtain absorption coefficients and to select a more accurate time of arrival of the reflected signal, the reconstruction of the rectangular waveform is provided.

When using adaptive algorithms, the frequency and duration of the subsequent measurement pulse can be determined based on various integral parameters, for example, depending on the intensity of the previous recorded pulse. This allows, for example, to increase the frequency and power of impulses at moments of unstable work of the heart to obtain more accurate bioinformation.

The signal is analyzed, compressed and sent to the memory block 6 and through the block 7 to the user's smartphone and then to the information storage and processing server.

The calculation of the cardiogram itself can be performed by decomposing the obtained sequence of the reflected signal intensity into a Fourier series with low-frequency filtering, followed by an inverse transformation to restore the desired value.

As shown in Fig. 5, the reflected pulses carry information about the biopotential values of the heart. Registration and processing of reflected impulses allows you to accurately determine all the parameters inherent in the ECG and transfer this data for storage, processing and analysis to any computerized systems, both within one medical institution, and between different institutions united by a common network or having access to patient data warehouse.

Claims (7)

1. A method for determining the parameters of the heart, consisting in the fact that - a stream of laser radiation is formed, which includes radiation from the first pair of sources with different wavelengths, each said source is provided with a means of converting laser radiation reflected from the human body into electrical signals, said laser radiation sources are diode, one of them is provided with a wavelength of 540 nm up to 550 nm, and the second - from 560 nm to 570 nm, while one of the mentioned sources provides longitudinal polarization, and the second - transverse, - an additional stream of laser radiation is generated from the second pair of diode sources of laser radiation with wavelengths from 520 nm to 528 nm and from 532 nm to 540 nm, respectively, each source of the second pair is provided with means for converting laser radiation into electrical signals, with one of the mentioned sources the second pair provide longitudinal polarization, and the second - transverse, - the above-mentioned flows irradiate tissues of a part of the human body, convert the radiation reflected from the tissues into electrical signals carrying information about the parameters of the heart, and on their basis, the biopotentials of the heart are determined. 2. The method according to claim 1, characterized in that the received electrical signals carrying information about the parameters of the heart are sent to a remote server, where they are correlated and summed. 3. A wearable electronic device for determining the parameters of the heart, containing means for processing electrical signals carrying information about the parameters of the heart, to implement the method according to claim 1. 4. An electronic device according to claim 3, characterized in that it is made in the form of an integrated microcircuit.

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