A portable multi-lead electrocardio monitoring system and electrocardio recorder

Abstract

The application relates to the technical field of electrocardio monitoring, in particular to a portable multi-lead electrocardio monitoring system and an electrocardio recorder, which comprises an electrocardio data acquisition module electrically connected to a plurality of lead electrode pieces to acquire electrocardio signals and perform digital-to-analog conversion processing on the electrocardio signals; a motion data acquisition module used for acquiring motion signals; a data processing module electrically connected to the electrocardio data acquisition module and the motion data acquisition module and used for acquiring the acquired electrocardio signals and motion signals to perform processing; a data storage module electrically connected to the data processing module and used for acquiring and regionally writing the processed electrocardio signals and motion signals to perform storage; and a data transmission module used for connecting the data processing module with external equipment in a wired and / or wireless mode to realize bidirectional data transmission. The application has the effect of comprehensively monitoring and recording electrocardio data through a portable electrocardio recording device.

Description

Technical Field

[0001] This application relates to the technical field of electrocardiogram (ECG) monitoring, and in particular to a portable multi-lead ECG monitoring system and ECG recorder. Background Technology

[0002] Continuous monitoring of electrocardiogram (ECG) data is necessary when providing medical care and daily monitoring for patients with heart disease. Hospital ECG recorders are connected to patients via multiple electrodes that monitor the electrical impulses in the heart and analyze these signals to obtain the patient's ECG data.

[0003] The standard 12-lead ECG instrument used in clinical practice requires patients to lie flat on the bed for a long time when measuring ECG data. This affects the patient's normal physiological activities. In addition, the large size and high cost of the equipment make it difficult for patients to use it effectively in daily situations such as at home or when going out.

[0004] Most portable ECG recorders currently use single-lead or three-lead modes. Although they can be easily attached to patients for daily monitoring without restricting normal activities, the small size of portable devices limits the acquisition of only partial monitoring data. The signal monitoring is unstable and incomplete, and cannot accurately and comprehensively reflect the twelve-lead ECG. Summary of the Invention

[0005] In order to achieve comprehensive monitoring and recording of electrocardiogram (ECG) data using a portable ECG recording device, this application provides a portable multi-lead ECG monitoring system and an ECG recorder.

[0006] In the first aspect, this application provides a portable multi-lead electrocardiogram monitoring system, which adopts the following technical solution:

[0007] A portable multi-lead electrocardiogram monitoring system, comprising:

[0008] An electrocardiogram (ECG) data acquisition module is electrically connected to several lead electrode pads to acquire ECG signals and performs digital-to-analog conversion processing on the ECG signals;

[0009] A motion data acquisition module is used to acquire motion signals, which include at least acceleration and attitude.

[0010] The data processing module is electrically connected to the ECG data acquisition module and the motion data acquisition module, and is used to acquire the acquired ECG signals and motion signals for processing including but not limited to feature extraction, data filtering, data compression, and interruption optimization.

[0011] A data storage module, electrically connected to the data processing module, is used to acquire and write the processed electrocardiogram signal and motion signal into different regions for storage.

[0012] The data transmission module enables the data processing module to connect to external devices via wired and / or wireless means to achieve bidirectional data transmission.

[0013] In some embodiments, the data processing module includes a feature extraction unit, a data filtering unit, and a pre-built DSP instruction set, specifically:

[0014] The data filtering unit retrieves a signed multiplication-accumulation instruction from the DPS instruction set to calculate the channel filtering value for each channel in the register.

[0015] The feature extraction unit retrieves the differential threshold method from the DPS instruction set to calculate the difference between the original sampled values ​​of adjacent sampling points, and determines the QRS wave initiation point based on the number of times the difference between the original sampled values ​​is greater than a preset value.

[0016] The feature extraction unit retrieves the multiplication and accumulation instruction from the DPS instruction set to calculate the sliding window mean of the RR intervals corresponding to the differences of each of the original sampled values;

[0017] The feature extraction unit retrieves the divider instruction from the DPS instruction set and calculates the heart rate value based on the mean of the sliding window of the RR interval.

[0018] In some embodiments, the data processing module includes a data compression unit, which is used for:

[0019] Obtain the original sampled values ​​corresponding to each channel, wherein the channel corresponds to the electrocardiogram signal and the motion signal;

[0020] Calculate the first difference between the current raw sample value and the previous raw sample value to generate an ECG data stream and a motion data stream;

[0021] The timestamps corresponding to each of the ECG data streams and the motion data streams are obtained for data organization. After the data organization, a write frame of fixed byte length is obtained to achieve single-channel data compression. The write frame includes at least a timestamp, data stream content, packet sequence number, checksum, and first compression tag.

[0022] Based on the first difference, the corresponding quantization step size is dynamically matched in the preset step size table, and the corresponding index adjustment rules are associated.

[0023] In some embodiments, the data processing module includes a data compression unit, which is further configured to:

[0024] The stability of the channels corresponding to each of the electrocardiogram signals and each of the motion signals is obtained, and the channel with the highest stability is respectively used as the electrocardiogram reference channel and the motion reference channel;

[0025] Based on the timestamp, calculate the second difference between the original sampled values ​​in the other channels and the ECG reference channel and the exercise reference channel to generate the ECG channel data stream and the exercise channel data stream;

[0026] The timestamps corresponding to the data streams between the ECG channels and the data streams between the motion channels are obtained for data organization. After the data organization, a write frame of fixed byte length is obtained to achieve data compression between channels. The write frame includes at least a timestamp, data stream content, packet sequence number, checksum, and second compression tag.

[0027] In some embodiments, the data transmission module includes a wired transmission module and a wireless communication module, wherein:

[0028] The data processing module determines whether the charging I / O port level is pulled high. If so, it controls the analog switch to open the path between the data storage module and the data processing module, and mounts the data processing module as a USB flash drive to read the electrocardiogram signal and the motion signal through the wired transmission module.

[0029] The wireless communication module connects to an external device via Bluetooth for wireless transmission. The wireless communication module is used to transmit the electrocardiogram signal, the motion signal and / or device information to the external device, and is also used to obtain the correction time and software package sent by the external device.

[0030] In some embodiments, the data processing module further includes an interrupt optimization unit, specifically used for:

[0031] Predefined interrupt priority rules, which include priority matching items and priority promotion items;

[0032] Obtain event information triggered by each module and identify the interrupt source corresponding to the event information;

[0033] The interrupt source is matched in the priority matching item to obtain the corresponding first priority;

[0034] Obtain information on simultaneously triggered combined events and determine whether the combined event information completely matches the priority enhancement item. If so, configure a corresponding second priority for the combined event information, wherein the second priority is greater than the first priority of each independent event information in the combined event information.

[0035] Determine whether the priority of the currently triggered interrupt source is greater than the priority of the current interrupt source;

[0036] If the value is greater than the specified value, the current interrupt source will be interrupted and forcibly suspended, and the corresponding processing action of the currently triggered interrupt source will be matched and performed. After the processing action is completed, the suspended processing action corresponding to the interrupt source will be resumed.

[0037] In some embodiments, the first priority of the interrupt source corresponding to each of the event information constituting the combined event information is lower than a preset priority.

[0038] In some embodiments, the interrupt optimization unit is further configured to:

[0039] Obtain the timestamp corresponding to each of the aforementioned event information;

[0040] If several timestamps are all within a preset time range and the interrupt sources corresponding to several event information are the same or the corresponding processing actions are the same, then the several event information will be interrupted and merged, and the processing action will be matched once to send the processing in parallel.

[0041] In some embodiments, the interrupt optimization module is further configured to:

[0042] Determine whether the interrupt source is the ECG data acquisition module or the motion data acquisition module;

[0043] If so, then obtain the current timestamp based on the event information;

[0044] When the interruption source is the ECG data acquisition module, the motion signal at the corresponding time is marked based on the timestamp;

[0045] When the interruption source is the motion data acquisition module, the electrocardiogram signal at the corresponding time is marked based on the timestamp.

[0046] Secondly, this application provides an electrocardiogram recorder, which adopts the following technical solution:

[0047] An electrocardiogram (ECG) recorder includes a host unit integrating the aforementioned portable multi-lead ECG monitoring system, and further includes several monitoring patches electrically connected to the host unit, wherein the monitoring patches include at least an auxiliary neutral electrode, several simulated limb electrodes, and several chest electrodes.

[0048] The technical solutions provided by the embodiments of this application have the following technical effects:

[0049] This system integrates a portable, small-sized ECG recorder, enabling low-power, compact ECG data acquisition, processing, analysis, and transmission at both the hardware and embedded levels. The resulting ECG recorder meets the requirements for portability and multi-lead data acquisition and analysis, providing more stable and comprehensive ECG monitoring while maintaining a small size. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of a single-board module of a portable multi-lead electrocardiogram monitoring system provided in this embodiment.

[0051] Figure 2 This is a schematic diagram of the appearance of the electrocardiogram recorder in the embodiments of this application.

[0052] Figure 3 This is a schematic diagram of the operation of the electrocardiogram recorder in the embodiments of this application.

[0053] Figure 4 This is a waveform diagram of electrocardiogram data recorded by an electrocardiogram recorder that integrates a portable multi-lead electrocardiogram monitoring system in an embodiment of this application.

[0054] Explanation of reference numerals in the attached diagram: 1. Electrocardiogram (ECG) data acquisition module; 2. Motion data acquisition module; 3. Data processing module; 4. Data storage module; 5. Data transmission module. Detailed Implementation

[0055] To better understand the purpose, technical solutions, and advantages of this application, it has been described and illustrated below with reference to the accompanying drawings and embodiments. However, those skilled in the art should understand that this application can be implemented without these details. In some cases, to avoid obscuring various aspects of this application due to unnecessary description, well-known methods, processes, systems, components, and / or circuits already described at a higher level will not be elaborated upon. It will be apparent to those skilled in the art that various modifications can be made to the embodiments disclosed in this application, and the general principles defined in this application can be applied to other embodiments and application scenarios without departing from the principles and scope of this application. Therefore, this application is not limited to the illustrated embodiments, but conforms to the broadest scope consistent with the scope of protection claimed in this application.

[0056] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0058] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples.

[0059] like Figure 1 As shown in the figure, this application discloses a portable multi-lead electrocardiogram monitoring system, including:

[0060] The ECG data acquisition module is electrically connected to several lead electrode pads to acquire ECG signals and perform digital-to-analog conversion processing on the ECG signals.

[0061] The ECG data acquisition module includes 10 patch electrodes with 12 leads and an ECG AFE chip, which forms 8 analog differential inputs. After passing through an RC radio frequency filter, the inputs are connected to 8 ADCs in the ECG AFE chip to filter out high-frequency radio frequency interference. All acquisition and analog-to-digital conversion are completed inside the AFE chip. The converted data is stored in its corresponding data register and sends a notification to the main controller. When data reading is required, the converted digital signal is subsequently transmitted to the data processing module via the SPI interface. This process is repeated to obtain the ECG data stream.

[0062] The motion data acquisition module is used to acquire motion signals, which include at least acceleration and attitude.

[0063] In this embodiment of the application, the motion data acquisition module is a 6-axis motion sensor of model LSM6DSLTR, which includes an acceleration monitoring unit and a gyroscope. It can be used to monitor at least acceleration data and 6-axis attitude trends, and is mainly used to monitor whether the user has fallen or is moving.

[0064] Similarly, the acquired motion signals are also converted from analog to digital by the configuration register of the motion data acquisition module through the main controller, so that the main controller can complete the analog-to-digital conversion of the motion signals according to a fixed sampling rate. The converted motion data is stored in its respective register and a notification is sent to the main controller. When data needs to be read, the converted digital signal will be transmitted to the data processing module through the SPI interface. This process is repeated to obtain the motion data stream.

[0065] The data processing module is electrically connected to the ECG data acquisition module and the motion data acquisition module. It is used to acquire the acquired ECG signals and motion signals for processing including but not limited to feature extraction, data filtering, data compression, and interrupt optimization.

[0066] In this embodiment, the data processing module is a wireless control chip nRF52832 with Bluetooth transmission function. It is mainly used to process the acquired electrocardiogram signals and motion signals. The data processing includes at least signal feature extraction, data filtering, data compression, and optimization processing of data interruption conflicts.

[0067] The data processing section is mainly handled by application software running on the Cortex-M4 core of the nRF52832. It can acquire 250 analog voltages per second and write them to the subsequent data storage module via SPI.

[0068] Compared to the traditional CC26240 chip, the nRF52832 has more I / O ports for connecting peripherals, and is smaller and consumes less power.

[0069] The data storage module, electrically connected to the data processing module, is used to acquire and write processed electrocardiogram and motion signals into different regions for storage.

[0070] The data storage module is connected to the nRF52832 and uses SD NAND flash with a capacity of 4GB. It uses PMOS to control its power supply to reduce the device's standby power consumption.

[0071] When operating normally, the nRF52832 controller operates the flash memory. When data is read by an external device, the flash memory needs to be accessed by the external device through the corresponding SD controller.

[0072] Therefore, it is necessary to switch the data bus of the data storage module. In this embodiment, the switching is controlled by two 2-channel USB switches.

[0073] During operation, the data storage module acquires processed ECG and motion signals and writes them into the SD NAND flash. The control chip nRF52832 is connected to the flash via an analog switch. When the system enters the working mode, the control chip controls the analog switch to open the path between the flash and the system, and then writes the data into the flash as a file. The file system used is FATFS.

[0074] The stored ECG and motion data streams will be written to two different files for separate storage. When reading this data later, you can read only the ECG data, only the motion data, or both based on synchronized timestamps.

[0075] The data transmission module enables the data processing module to connect to external devices via wired and / or wireless means to achieve bidirectional data transmission.

[0076] The data transmission module is used to transmit electrocardiogram signals and / or motion signals to an external device via wired or wireless means when data acquisition is required. In this application, the wired method is a USB-based wired transmission connection, and the wireless method is a Bluetooth communication connection.

[0077] The wired interface configured in this application is a Type-C external interface, through which data stored in the internal flash memory can be read.

[0078] In this application, the wireless refers to the Bluetooth module configured for the nRF52832 chip, whose radio frequency is single-ended output.

[0079] like Figure 4 As shown, the above steps enable the integrated configuration of a portable small ECG recorder, achieving low-power, small-volume ECG data acquisition, processing, analysis, and transmission at both the hardware and embedded levels. The ECG recorder obtained based on this system meets the requirements for portability and multi-lead data acquisition and analysis, and provides more stable and comprehensive ECG monitoring while maintaining a small size.

[0080] In other embodiments, a power module, a download interface, and indicator lights are also included.

[0081] The power module includes a lithium battery and a DC-DC converter built into the nRF52832 chip. The lithium battery is first regulated by the DC-DC converter before supplying power to the main chip nRF52832 and other modules. The ECG acquisition section is powered by an I / O port of the nRF52832 chip, which can be completely shut down in standby mode to reduce standby power consumption.

[0082] The download interface is the SWD interface, with 6 test points: GND, RESETn, SWDIO, SWDCLK, VCC, and SW0.

[0083] Among them, RESETn is the reset pin, used to wake up the main chip MCU in low power mode; SW0 is the serial output pin, used to transmit debug trace signals. Together with the read and write functions of SWDIO and SWDCLK, they form a complete debug link.

[0084] Meanwhile, indicator lights are set on the system board. In this application, there is one blue LED and one orange LED to indicate the status of the device during use.

[0085] In other embodiments, an RTC module and a logging module are also included.

[0086] The RTC module is a timing unit independent of the main controller, powered directly from the battery. The main controller communicates with the RTC module through the IIC interface and can read and modify the internally recorded events. When the host and mobile device are connected via Bluetooth, the host can obtain the events of the mobile device to correct the events inside the RTC module. The main controller monitors the battery capacity and forces the RTC module into a low-power state when the battery capacity is too low. The remaining battery power can guarantee that the RTC module will work for 100 days.

[0087] In this embodiment of the application, the RTC module selected is the extremely low-power EPSON REX8111.

[0088] The log module records various states during the host's operation. The implementation method is that the main controller writes the log information to the flash as a file, which is the same as the method of writing ECG data stream and motion data stream. By partitioning different file names, the required information is obtained by reading the log file in the transmission mode.

[0089] In other embodiments, the data processing module includes a feature extraction unit, a data filtering unit, and a pre-built DSP instruction set. The DSP instruction set is a collection of DSP instructions configured using the built-in Cortex-M4 core of the nRF52832. Each DSP instruction is assigned to a processing device on the nRF52832. Specifically:

[0090] The data filtering unit retrieves a signed multiply-accumulate instruction from the DPS instruction set to calculate the channel filtering value for each channel in the registers.

[0091] For electrocardiogram (ECG) data, the most crucial aspect is the feature extraction of the QRS, P, and T waves. Traditional ECG instruments rely on software algorithms to calculate these features, which is time-consuming. This application, however, utilizes embedded software within its hardware to achieve rapid internal feature extraction after ECG data acquisition. This feature extraction is implemented based on the hardware's unique structure and functionality. By fully leveraging the main control chip's computing resources and overcoming the computational limitations of embedded platforms through instruction-level optimization, a pipelined processing workflow of "real-time acquisition - feature extraction - transmission" is achieved.

[0092] First, data reception, buffering, and filtering are performed.

[0093] During the receive buffering process, the eight digital ECG signals output by the AFE chip are received via the SPI interface and buffered in the SRAM of the nRF52832.

[0094] Configure the nRF52832's SPI peripheral to "interrupt mode" so that the SPI interrupt is triggered when the AFE948 data is ready (DRDY pin level transition);

[0095] In the interrupt service routine, eight data streams are read in batches (8 × 24 bits = 24 bytes each time) through the FIFO of the hardware SPI controller and stored in the circular buffer of SRAM (size 250 × 24 bytes, which can buffer 1 second of data) to avoid data overflow.

[0096] During the filtering process, the original data is filtered (50Hz power frequency interference suppression and baseline drift removal) to reduce the impact of noise on feature extraction.

[0097] A second-order IIR filter is used, and its difference equation is y[n]=2*cos(2π*50 / fs)*y[n-1]-y[n-2]+x[n]-2*cos(2π*50 / fs)*x[n-1] + x[n-2] (fs=250Hz).

[0098] x[n] represents the input signal, i.e. the original acquired signal, which corresponds to the unprocessed electrocardiogram signal (the digital quantity after analog-to-digital conversion) and the original motion signal acquired by the 6-axis sensor.

[0099] y[n] represents the output signal, that is, the signal after filtering.

[0100] n represents the sampling point index (time sequence marker) at the current time, n-1 is the "previous sampling point", and n-2 is the "two previous sampling points".

[0101] 2π*50 represents the angular frequency of 50Hz. Dividing this by the sampling rate fs yields the normalized angular frequency. The cosine value is used to determine the pole / zero locations of the filter, ensuring maximum attenuation of the 50Hz signal.

[0102] The DSP can accelerate the filtering process based on multi-channel filtering. In traditional filtering, the 8-channel signal is processed in a loop of "input-coefficient multiplication-accumulation-output" based on software implementation. Single-channel filtering requires 32 operations. However, this application can call signed multiplication and accumulation from the DSP instruction set to complete (register 1*register 2) + register 3 → register 4 in one clock cycle, supporting parallel processing of multiplication and accumulation of 4-channel signals, thereby compressing multi-channel data filtering.

[0103] The feature extraction unit retrieves the differential threshold method from the DPS instruction set to calculate the difference between the original sampled values ​​of adjacent sampling points, and determines the QRS wave initiation point based on the number of times the difference between the original sampled values ​​is greater than a preset value.

[0104] The differential threshold method is retrieved from the DPS instruction set to calculate the difference between adjacent sampling points, diff[n] = |x[n] - x[n-1]|. When the difference between the original sampling values, diff[n], exceeds the preset dynamic threshold three times consecutively, it is determined that this is the start point of the QPS wave. In this embodiment, the dynamic threshold is 60% of the maximum value in the previous 5 seconds.

[0105] The feature extraction unit retrieves the multiplication and accumulation instruction from the DPS instruction set to calculate the mean of the sliding window of the RR interval corresponding to the difference of each original sample value.

[0106] The sliding window mean of the absolute values ​​of each difference calculated by the above difference threshold method is used to batch calculate the difference values ​​calculated by the MAC (multiplication and accumulation) instruction, which replaces the traditional cyclic accumulation and improves the calculation efficiency.

[0107] The sliding window mean can calculate the average value of continuous sampling points, smooth the high-frequency signal in the signal, improve the data quality, and obtain the time interval between the peak values ​​of two R waves in each QRS wave as defined as the RR interval.

[0108] The feature extraction unit retrieves the divider instruction from the DPS instruction set and calculates the heart rate value based on the mean of the sliding window of the RR interval.

[0109] After calculating an accurate and smooth RR interval, the heart rate value is calculated based on the RR interval by calling the divider instruction in the DPS instruction set.

[0110] In traditional solutions, this is achieved through software division functions, which takes a long time for a single calculation.

[0111] In this embodiment, an unsigned division instruction is first obtained from the DPS instruction set, and the Cortex-M4's hardware divider is invoked. The RR interval (unit: ms) is stored in register a, and 60000 is stored in register b. The division instruction is executed to directly perform the division calculation in register c and convert it into a heart rate value (beats / minute). Specifically, heart rate = 60000 / RR interval. All processes are performed in hardware, using a hardware-implemented division instruction to replace the software division operation, thus reducing the overall data analysis and calculation time.

[0112] In other embodiments, the data processing module includes a data compression unit, which is used for:

[0113] Obtain the original sampled values ​​corresponding to each channel, where each channel corresponds to an electrocardiogram signal and a motion signal.

[0114] ECG and motion data are acquired through several channels to achieve differential input. In order to reduce subsequent transmission time and storage space, this application also requires compression of the ECG and motion data streams in each channel.

[0115] In this application, the data compression within each channel is performed using the ADPCM adaptive differential pulse code modulation method.

[0116] Both ECG and motion data exhibit waveform continuity, resulting in minimal differences between adjacent sample values. Therefore, the ADPCM compression method is quite effective.

[0117] Calculate the first difference between the current raw sample value and the previous raw sample value to generate the ECG data stream and motion data stream.

[0118] When the original sample value is obtained, this application does not directly store the original sample value (e.g., 16 bits), but records the difference between the current sample and the previous sample, and represents the difference with smaller bits, such as 4 bits.

[0119] The timestamps corresponding to each ECG data stream and motion data stream are obtained for data organization. After data organization, a fixed-byte length write frame is obtained to achieve single-channel data compression.

[0120] Before being written to flash memory, the compressed ECG and accelerometer data streams are reorganized and converted into fixed-byte length frames. Each frame contains a timestamp, packet number, checksum, data stream content, and first compression tag.

[0121] The timestamp represents the time when the data was sampled, the packet sequence number represents the order of the data packets sent and received, each frame of data corresponds to a unique packet sequence number, the checksum is used to verify the integrity and accuracy of the frame in data communication, and the first compression tag is used to indicate that the frame data is obtained based on the compression method of the data in each channel.

[0122] Based on the first difference, the corresponding quantization step size is dynamically matched in the preset step size table, and the corresponding index adjustment rules are associated.

[0123] The compression ratio is 1:4 under normal circumstances. The quantization step size can be dynamically adjusted according to the difference magnitude. For example, the step size is increased when the difference is large and decreased when the difference is small, to ensure that 4 bits can always cover the entire difference range.

[0124] At the same time, adaptive control of quantization accuracy is achieved through predefined index adjustment rules.

[0125] In the above scheme, compression is performed on the data of each channel separately, without considering the signal correlation between channels, such as the correlation between ECG waveforms of different leads and the synchronization between motion and ECG data. Therefore, it cannot reflect the differences in waveform data between channels.

[0126] Therefore, in some other embodiments, the data processing module includes a data compression unit, which is further used for:

[0127] The stability of each ECG signal and each motion signal is obtained, and the channel with the highest stability is used as the ECG reference channel and the motion reference channel, respectively.

[0128] First, select the most stable channel from the several channels corresponding to the ECG signal and the several channels corresponding to the motion signal as the reference channel. For example, if the ECG data in lead II of the ECG signal is stable, then the channel corresponding to that lead can be used as the reference channel. Similarly, if the data corresponding to the x-axis in the 6-axis is relatively stable, then the channel corresponding to that lead can be used as the reference channel.

[0129] The sampled value corresponding to the reference channel can be used as a reference value.

[0130] Based on the timestamp, the second difference between the original sampled values ​​in other channels and the ECG reference channel and the exercise reference channel is calculated to generate the ECG channel data stream and the exercise channel data stream.

[0131] Taking ECG data as an example, the sampled values ​​of all ECG channels other than the reference channel are compared with the sampled values ​​of the reference channel. The dynamic range of the difference should be smaller than that of the original signal. Then, the second difference is compressed based on the ADPCM algorithm.

[0132] It is important to note that when calculating the second difference, the values ​​used for the difference calculation between each channel must be under the same timestamp to avoid decompression misalignment caused by time offset.

[0133] By compressing the signals between channels, the most stable lead or axis is used as a reference. The difference between the overall data of other channels and the overall data of the baseline channel is calculated and compressed. The compression process directly preserves the differential relationship between channels. After decompression, the relative waveform characteristics of multiple channels can be directly restored, such as the difference in ST segment offset in different leads of ECG and the coordinated change of triaxial acceleration during exercise, without the need for additional algorithms to reconstruct the channel relationship.

[0134] The timestamps corresponding to the data streams between ECG channels and between motion channels are obtained for data organization. After data organization, a fixed-byte length write frame is obtained to achieve data compression between channels. The write frame includes at least a timestamp, data stream content, packet sequence number, checksum, and second compression tag.

[0135] Similar to single-channel data compression, after inter-channel data compression, the data is reorganized and converted into fixed-byte length as write frames before being written to flash. Each frame includes at least a timestamp, data stream content, packet sequence number, checksum, and second compression tag.

[0136] Meanwhile, the second compression tag is used to indicate that the frame data is obtained by differential calculation based on the data between each channel to compress it.

[0137] By analyzing frame data obtained from different compression methods and compression objects, the compression tags in the frame data indicate to the system the specific compression method. When decompressing the frame data during subsequent data reading, the decompression method must be matched. If the write frame with the first compression tag is decompressed, the continuous ECG or motion signal at each time in each channel is obtained. If the write frame with the second compression tag is decompressed, the relative waveform characteristics at the corresponding timestamps of each channel, the coordination results of motion data, and the waveform deviation of different leads at the same time are obtained.

[0138] In other embodiments, the data transmission module includes a wired transmission module and a wireless communication module, wherein:

[0139] The data processing module determines whether the charging I / O port level is pulled high. If so, it controls the analog switch to open the path between the data storage module and the data processing module, and mounts the data processing module as a USB flash drive to read ECG and motion signals through the wired transmission module.

[0140] The wired transmission module transmits ECG and motion data stored in the host flash memory to the computer. When the host is connected to the computer via USB cable, the main controller detects that the charging I / O port level is high and enters wired transmission mode. In transmission mode, the main controller's analog switch opens the path between the card reader IC and the flash memory. The computer will mount the host's flash memory as a USB flash drive and directly read the ECG and motion data files from the USB flash drive to obtain the corresponding data.

[0141] The wireless communication module connects to external devices via Bluetooth for wireless transmission. The wireless communication module is used to transmit ECG signals, motion signals and / or device information to external devices, and also to obtain calibration time and software packages sent by external devices.

[0142] The Bluetooth communication module enables wireless data transmission. Other devices, such as mobile phones, computers, and watches, can obtain information such as the host's battery level, memory capacity, ECG data, and exercise data through Bluetooth, and can also modify the host's configuration. The host, in turn, can obtain calibration time and software packages for program upgrades via Bluetooth.

[0143] In other embodiments, the data processing module further includes an interrupt optimization unit, specifically used for:

[0144] An interrupt is a real-time notification sent by a hardware module to an MCU chip, which is generated when the device needs to respond to dynamically changing external or internal states.

[0145] For example, if the AFE ECG chip completes one ECG data sampling, it must immediately notify the host to read the data; otherwise, it will cause FIFO overflow and data loss. If the six-axis sensor detects a user falling, it must trigger an alarm.

[0146] The change of this state and the triggering of actions both correspond to an interrupt.

[0147] Meanwhile, different interrupts correspond to different times and require different processing solutions. If the system does not recognize the interrupt, the main control chip cannot distinguish between "AFE data ready (signal needs to be read)" and "fall detection (alarm needs to be triggered)," which will lead to confusion in the processing logic.

[0148] Different hardware modules correspond to different interrupt sources. Only by accurately identifying the specific object of the interrupt source and the priority of different interrupt sources can the correct processing logic be sent to the more urgent interrupts, avoiding conflicts caused by multiple interrupts in a short period of time.

[0149] Predefined interrupt priority rules, which include priority matching items and priority promotion items.

[0150] First, obtain the predefined interrupt priority rules to configure appropriate priorities for different interrupt sources later.

[0151] Interrupt priority includes priority matching items and priority boosting items. Priority matching items represent the basic priority configured for an interrupt source, while priority boosting items represent the configuration items that boost the priority for special interrupts or combined interrupts.

[0152] Match the interrupt source in the priority matching item to obtain the corresponding first priority.

[0153] Obtain event information triggered by each module and identify the interrupt source corresponding to the event information.

[0154] Different interrupt sources have different base priorities, such as:

[0155] Highest priority: Sudden interruption of electrode contact impedance, requiring power supply to be woken up, with a response time of less than 1ms.

[0156] High priority: If the AFE ECG data is ready to be interrupted, the host should be notified in a timely manner to read the data in order to avoid FIFO overflow.

[0157] Medium priority: The six-axis sensor's fall detection is interrupted, and an alarm should be triggered.

[0158] Low priority: RTC clock module timer interrupt.

[0159] Then, the interrupt source corresponding to the triggered event can be matched with the corresponding priority information in the interrupt priority rules.

[0160] When the electrode impedance is interrupted, the contact impedance of electrodes V4 and V6 in the 10 electrodes drops below the threshold. The hardware comparator outputs a high level, which is connected to the PPI (Programmable Peripheral Interconnect) module of the nRF52832, directly triggering the DC-DC enable signal. At the same time, an interrupt is generated to notify the main control chip. (In standby mode, the switching chip connects electrodes V4 and V6 to the pull-up resistor and GND respectively to leave them floating. The voltage divider resistor in the circuit turns on the MOSFET, thereby grounding the power supply enable pin and turning off the power supply. When the electrode is connected to the human body, the resistor in the circuit is connected in parallel with the human body resistance to form a voltage divider. This voltage divider is much smaller than the voltage when there is no human contact, so the MOSFET cannot turn on, thereby pulling up the power supply enable pin and starting the power supply to provide power.)

[0161] When the AFE ECG data ready interruption occurs, its DRDY pin outputs a low-level pulse after each frame of data conversion is completed, triggering the interrupt;

[0162] When the six-axis sensor is interrupted, its INT1 pin outputs a high level when it detects a fall characteristic (acceleration greater than 8g and angular velocity greater than 1000 / s), triggering an external interrupt.

[0163] When the RTC clock is interrupted, the INT pin of the clock outputs an interrupt every second to update the system timestamp.

[0164] By identifying the interrupt source, different priorities are matched to each triggered event. Subsequently, when interrupt conflicts occur, the priority is used to determine which interrupts need to be processed first, so as to avoid low-priority interrupts blocking high-priority events.

[0165] Get information on the combined events that are triggered simultaneously, and determine whether the combined event information completely matches the priority boosting item. If so, configure the corresponding second priority for the combined event information.

[0166] Some events are the result of a combination of responses from multiple hardware components. For example, when a user falls and the electrode pads fall off, it will simultaneously trigger an abnormal interruption of the six-axis sensor and the AFE ECG data. At this time, there is a correlation between multiple interrupts. When the combined event information resulting from this correlation matches the priority increase item, the second priority corresponding to the combined event information needs to be dynamically adjusted, because the event resulting from the combination of multiple interrupts should have a higher processing priority than a single event.

[0167] At the same time, the interrupt priority corresponding to the combined event must be higher than the priority corresponding to each individual event interrupt source in the combined event.

[0168] If the six-axis sensor interruption corresponds to priority 3 and the AFE ECG data abnormality interruption corresponds to priority 2, then the combined event that triggers both the six-axis sensor interruption and the AFE ECG data abnormality interruption must have a priority of at least priority 1, which is higher than priority 2 and priority 3.

[0169] Determine whether the priority of the currently triggered interrupt source is greater than the priority of the current interrupt source.

[0170] If the value is greater than the specified value, the current interrupt source will be interrupted and forcibly suspended, and the corresponding processing action of the currently triggered interrupt source will be matched and performed. After the processing action is completed, the processing action corresponding to the suspended interrupt source will be resumed.

[0171] In this embodiment, an interrupt nesting mechanism is adopted. When a high-priority interrupt occurs and a low-priority interrupt is currently being processed, the high-priority interrupt is allowed to preempt the interrupt service of the low-priority interrupt. For example, an electrode impedance interrupt (priority 2) can interrupt an RTC interrupt that is currently being executed (priority 4).

[0172] It is important to note that when a high-priority interrupt preempts the interrupt service routine of a low-priority interrupt, the low-priority interrupt will record its context and be suspended in the interrupt service routine (ISR). Once the high-priority interrupt has finished processing, the suspended low-priority interrupt will be resumed and the unfinished processing will be performed again based on the context information.

[0173] In other embodiments, the interrupt optimization unit is further configured to:

[0174] Get the timestamps corresponding to each event.

[0175] When an event occurs, the timestamp information corresponding to the event is obtained from the RTC module through the corresponding interrupt source.

[0176] If several timestamps are all within a preset time range and the interrupt sources or processing actions corresponding to several event information are the same, then the several event information will be merged into an interrupt and matched with a single processing action for parallel processing.

[0177] When the timestamp shows that a device has multiple interrupts of the same type or multiple modules have parallel interrupts but the processing actions are the same within a short period of time, such as receiving more than 3 RTC timer interrupt messages within 100ms, the interrupt optimization unit will automatically merge several interrupts of the same type or interrupts with the same processing actions into one for processing.

[0178] This reduces the computational load on the MCU, because each interrupt requires a context switch. For example, during an RTC interrupt, the context switches between saving and restoring the register state, which takes multiple switching times. However, when multiple short-duration interrupts of the same type are merged into one interrupt, only one context switch is needed to provide interrupt service. At the same time, the merged interrupt events can be processed in batches because they are of the same type or have the same processing action, avoiding frequent wake-ups of the interrupt service routine and improving system stability.

[0179] Furthermore, when merging multiple interrupts, all interrupts to be merged must correspond to low-priority interrupts. This is because low-priority interrupts have lower requirements for processing timeliness and responsiveness, and can therefore be merged. High-priority interrupts, on the other hand, have higher requirements for processing timeliness and responsiveness, and therefore cannot be merged.

[0180] In other embodiments, the interrupt optimization module is also used for:

[0181] Determine whether the interrupt source is the ECG data acquisition module or the motion data acquisition module;

[0182] If so, then obtain the current timestamp based on the event information;

[0183] When the interrupt source is the ECG data acquisition module, the motion signal at the corresponding time is marked based on the timestamp;

[0184] When the interrupt source is the motion data acquisition module, the ECG signal at the corresponding time is marked based on the timestamp.

[0185] In this embodiment, the DRDY pin (data ready) of the AEF ECG chip is electrically connected to the trigger input pin INT2 of the six-axis sensor. After the AEF ECG chip completes one ECG data sampling, the rising edge of the DRDY signal triggers the six-axis sensor LSM6DSLTR to synchronously acquire one motion signal (acceleration data and angular velocity data) and bind them. The sampling time of the two is recorded by the RTC module.

[0186] By comparing synchronously acquired motion data and electrocardiogram (ECG) data, when any module generates event information and acts as an interrupt source, if the amplitude of the corresponding event information is greater than a preset value, the data at the corresponding time point is marked. For example, when the six-axis sensor detects an acceleration greater than 2g, the ECG data at the corresponding time is marked as "suspected interference"; when the ECG data reflects a sharp increase in heart rate, the motion data at the corresponding time is marked as "suspected interference".

[0187] By synchronizing time, precise correlation between "exercise-ECG" data is achieved. When either exercise data or heart rate data shows an abnormality, the other data is marked simultaneously to determine whether the heart rate abnormality is caused by changes in exercise and whether changes in exercise data have affected ECG data.

[0188] Furthermore, when any of the ECG data or motion data is interrupted, the combined data of the events before and after the abnormal event (abnormal data + marked data) is constructed into key data and stored in a dedicated partition of the SD NAND Flash.

[0189] like Figure 2 and Figure 3 As shown, this application also discloses an electrocardiogram recorder, including a host integrating the above-mentioned portable multi-lead electrocardiogram monitoring system, and several monitoring patches electrically connected to the host, wherein the monitoring patches include at least auxiliary neutral leads, several simulated limb leads and several chest leads.

[0190] The monitoring patch is connected to the host via leads. Additionally, adhesive pads are provided on the host and each lead to attach the host and each lead to the user's body.

[0191] Furthermore, in the embodiments of this application, each monitoring patch and its corresponding adhesive pad together constitute a circular lead electrode. The monitoring patches can also be designed in any shape, such as a matrix or triangle, as long as it does not affect the adhesion effect and the ECG recording effect.

[0192] In this embodiment, the electrocardiogram recorder is a 12-lead portable monitor, and the 12-lead electrocardiogram data is calculated from the electrocardiogram data monitored by 10 electrode patches.

[0193] The 10 electrode patches in this application include an auxiliary neutral electrode R, an electrode R simulating a right arm lead, an electrode L simulating a left arm lead, an electrode F simulating a left leg lead, a chest electrode C1, a chest electrode C2, a chest electrode C3, a chest electrode C4, a chest electrode C5, and a chest electrode C6.

[0194] Specifically, electrode R is attached to the right infraclavicular fossa region during operation; electrode N is attached to the midline below the clavicle; electrode L is attached to the left infraclavicular fossa region; electrode F is attached to the right costal arch; electrode C1 is attached to the 4th intercostal space at the right sternal border; electrode C2 is attached to the 4th intercostal space at the left sternal border; electrode C3 is attached to the midpoint between the 4th intercostal space at the left sternal border and the 5th intercostal space at the left midclavicular line; electrode C4 is attached to the 5th intercostal space at the left midclavicular line; electrode C5 is attached to the 5th intercostal space at the left anterior axillary line; and electrode C6 is attached to the 5th intercostal space at the left midaxillary line.

[0195] By using chest R (RA), L (LA), and F (LL / RL) electrodes to simulate limb electrodes, the complexity of wearing the device is reduced, while still being able to collect signals similar to "leads I, II, and III".

[0196] The role of the auxiliary neutral electrode is to serve as a reference point for approximately zero potential. Other leads use the neutral electrode as a reference to calculate the relative voltage difference between the cardiac electrical signals of each other electrode and the neutral electrode.

[0197] The potential difference relative to N measured in lead R (simulating right arm RA) is VR;

[0198] The potential difference relative to N measured in lead L (simulating left arm LA) is VL;

[0199] The potential difference relative to N measured in lead F (simulating the left leg LL) is VF.

[0200] The potential difference data of leads I, II, and III can be obtained by calculating the difference between the relative voltage differences of the electrodes of each simulated limb.

[0201] Lead I (potential difference between LA and RA) = VL - VR (because LA potential ≈ VL, RA potential ≈ VR, the difference is the signal in lead I).

[0202] Lead II (potential difference between LL and RA) = VF - VR (similarly, LL potential ≈ VF, RA potential ≈ VR, and the difference is the signal in lead II).

[0203] Lead III = II - I, which is the potential difference between LL and LA, corresponding to the traditional lead III;

[0204] Lead aVR = -(I+II) / 2 (pressurized unipolar right upper limb lead, reflecting the electrical activity on the right side of the heart);

[0205] Lead aVL = I - II / 2 (pressurized unipolar left upper limb lead, reflecting the electrical activity on the left side of the heart);

[0206] Lead aVF=II-I / 2 (pressurized unipolar left lower limb lead, reflecting the electrical activity of the inferior wall of the heart).

[0207] C1-C6 correspond to V1-V6, fully covering the electrical activity of the anterior and lateral walls of the heart, meeting the needs of dynamic electrocardiogram monitoring for detecting myocardial ischemia and arrhythmias.

[0208] The implementation principle is as follows:

[0209] like Figure 2 and Figure 4 As shown, a portable miniature ECG recorder is integrated and configured, realizing low-power, small-volume ECG data acquisition, processing, analysis, and transmission from both hardware and embedded levels. The ECG acquisition device obtained based on this system meets the requirements of portability and multi-lead data acquisition and analysis, and provides more stable and comprehensive ECG monitoring while maintaining a small size.

[0210] It should be understood that although the steps in the flowcharts in the accompanying drawings are shown sequentially as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise expressly stated herein, there is no strict order in which these steps are performed, and they may be performed in other orders.

[0211] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A portable multi-lead electrocardiogram monitoring system, characterized by, The application relates to a wearable ECG device, which comprises: an ECG data acquisition module electrically connected to a plurality of lead electrode pads to acquire ECG signals and perform digital-analog conversion on the ECG signals; a motion data acquisition module for acquiring motion signals, the motion signals at least including acceleration and attitude; a data processing module electrically connected to the ECG data acquisition module and the motion data acquisition module, in particular, the data processing module comprises a Cortex-M4 core, the Cortex-M4 core is pre-built with a DSP instruction set, and calculation instructions are called from the DSP instruction set based on processing requirements to synchronously complete processing including but not limited to feature extraction, data filtering, data compression and interruption optimization in a plurality of registers for the acquired ECG signals and motion signals, the calculation instructions include signed multiply-accumulate instructions, differential threshold method, multiply-accumulate instructions and unsigned division instructions; when the data processing module performs data compression, the data compression includes intra-channel data compression and inter-channel data compression, the intra-channel compression corresponds to a first compression label, and the inter-channel compression includes a second compression label; when the data processing module performs interruption optimization, time stamps corresponding to event information of each interruption are acquired, if a plurality of the time stamps are all within a preset time range and a plurality of interruption sources corresponding to the event information are the same or processing actions corresponding to the event information are the same, a plurality of the event information are combined and matched with the processing action once to be delivered for parallel processing, and when the interruption combination is performed, all the combined event information correspond to the minimum priority; a data storage module electrically connected to the data processing module for acquiring and writing the processed ECG signals and motion signals in different regions to be stored; a data transmission module for connecting the data processing module with external equipment in a wired and / or wireless mode to realize bidirectional data transmission.

2. The portable multi-lead cardiac monitoring system of claim 1, wherein, The data processing module comprises a feature extraction unit and a data filtering unit, in particular, the data filtering unit calls signed multiply-accumulate instructions in the DSP instruction set to calculate channel filtering values of channels in each register; the feature extraction unit calls differential threshold method in the DSP instruction set to calculate original sampling value differences of adjacent sampling points and determines a QRS wave starting point based on a number of times that the original sampling value difference is greater than a preset value; the feature extraction unit calls multiply-accumulate instructions in the DSP instruction set to calculate a sliding window mean value of an R-R interval corresponding to each original sampling value difference; the feature extraction unit calls divider instructions in the DSP instruction set and calculates a heart rate value based on the sliding window mean value of the R-R interval.

3. The portable multi-lead cardiac monitoring system of claim 1, wherein, The data processing module comprises a data compression unit, which is used for: acquiring original sampling values corresponding to each channel, wherein the channels correspond to the ECG signals and the motion signals; calculating a first difference value between a current original sampling value and a previous original sampling value to generate ECG data streams and motion data streams; The timestamps corresponding to the ECG data streams and the motion data streams are acquired for data organization, and fixed byte length write frames are obtained after the data organization to realize single-channel data compression, the write frames at least including timestamps, data stream contents, packet serial numbers, check codes, and first compression tags; Based on the first difference value, a corresponding quantization step is dynamically matched in a preset step table, and a corresponding index adjustment rule is associated.

4. The portable multi-lead cardiac monitoring system of claim 3, wherein, The data processing module includes a data compression unit, which is further configured to: Corresponding channel stabilities of the ECG signals and the motion signals are acquired, and the channel with the highest stability is taken as an ECG reference channel and a motion reference channel, respectively; Based on the timestamps, second difference values between the original sampling values of other channels and the ECG reference channel and the motion reference channel are calculated to generate ECG inter-channel data streams and motion inter-channel data streams; The timestamps corresponding to the ECG inter-channel data streams and the motion inter-channel data streams are acquired for data organization, and fixed byte length write frames are obtained after the data organization to realize inter-channel data compression, the write frames at least including timestamps, data stream contents, packet serial numbers, check codes, and second compression tags.

5. The portable multi-lead cardiac monitoring system of claim 3 or 4, wherein, The data transmission module includes a wired transmission module and a wireless communication module, wherein: The data processing module judges whether the charging IO port level is pulled high, if yes, controls an analog switch to open a path between the data processing module and the data storage module, and mounts the data processing module as a U disk to read the ECG signals and the motion signals through the wired transmission module; The wireless communication module is connected with an external device through Bluetooth to perform wireless transmission, and is configured to transmit the ECG signals, the motion signals, and / or device information to the external device, and acquire a correction time and a software package issued by the external device.

6. The portable multi-lead cardiac monitoring system of claim 1, wherein, The data processing module further includes an interrupt optimization unit, which is specifically configured to: Predefine an interrupt priority rule, the interrupt priority rule including a priority matching item and a priority promotion item; Acquire event information triggered by each module, and identify interrupt sources corresponding to the event information; Match the interrupt sources in the priority matching item to acquire corresponding first priorities; Acquire combined event information triggered simultaneously, and judge whether the combined event information is completely matched with the priority promotion item, if yes, configure the combined event information with a corresponding second priority, wherein the second priority is greater than first priorities of each independent event information in the combined event information; Judge whether a priority of the interrupt source currently triggered is greater than a priority of the interrupt source currently triggered; If greater, interrupt and forcibly suspend the interrupt source currently triggered, match a processing action corresponding to the interrupt source currently triggered to perform, and restore the processing action corresponding to the suspended interrupt source after the processing action ends.

7. The portable multi-lead cardiac monitoring system of claim 6, wherein: The first priorities of the interrupt sources corresponding to each event information constituting the combined event information are all lower than a preset priority.

8. The portable multi-lead cardiac monitoring system of claim 7, wherein, The interrupt optimization module is further configured to: determining whether the interrupt source is the electrocardiogram data acquisition module or the motion data acquisition module; if yes, obtaining the current time stamp based on the event information; when the interrupt source is the electrocardiogram data acquisition module, marking the motion signal corresponding to the time based on the time stamp; when the interrupt source is the motion data acquisition module, marking the electrocardiogram signal corresponding to the time based on the time stamp.

9. A cardiac event recorder, comprising: The host computer integrating the portable multi-lead electrocardiogram monitoring system as claimed in any one of claims 1-8, further comprising a plurality of monitoring patches electrically connected to the host computer, wherein the monitoring patches at least include an auxiliary neutral electrode, a plurality of analog limb electrodes and a plurality of chest electrodes.

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