Calculation method and application of effective contact rate of electrocardio-electrode

Abstract

The invention provides a method for calculating the effective contact rate of an electrocardio-electrode and application, based on the characteristic that lead signals are formed among RA, LA and LL electrodes, whether the contact of the electrodes is effective or not is judged by judging the quality of the lead signals, the effective rate of the electrode contact is calculated under the condition of long-term wearing, and further, the effective contact rate of the electrodes can be calculated by combining the quality of the lead signals. Furthermore, the effective rate of chest lead electrode contact is judged by the same method, so that the production process of the electrocardio-electrode is evaluated, guidance is optimized, or a basis and an instruction for wearing adjustment are provided for a user.

Description

Technical Field

[0001] The present invention relates to the field of wearable device electrocardiogram (ECG) monitoring, and in particular to a method for calculating an ECG electrode contact rate and an application thereof. Background Art

[0002] As a comprehensive manifestation of cardiac electrical activity on the body surface, the human electrocardiogram (ECG) contains a wealth of physiological and pathological information reflecting cardiac rhythm and its electrical conduction, and has a very high application value in evaluating cardiac function and diagnosing heart disease. Nowadays, with the development of smart electronic devices, more and more wearable devices that can monitor human physiological signals have appeared on the market, and the acquisition of human electrocardiograms has gradually expanded from in-hospital examinations to out-of-hospital monitoring, among which wearable devices that monitor ECG are the majority.

[0003] ECG wearable devices usually include multi-lead wearable devices such as ECG vests and heart rate belts. Such devices are equipped with ECG electrodes, which are in direct contact with the human body surface to collect ECG signals. However, most of the ECG electrodes of wearable devices are dry electrodes, which have high requirements for electrode contact and adhesion. When wearable devices are worn, the ECG electrodes may not be in proper contact with the body surface, resulting in the collected ECG signals being of low quality or even completely interference signals. For multi-lead wearable devices, when the ECG signal quality does not meet the standards, it is of great significance to be able to promptly determine which specific electrode has unstable contact. Summary of the invention

[0004] The present invention aims at solving the problems in the prior art and provides a method for calculating an electrocardiogram electrode contact rate and an application thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for calculating an effective contact rate of an electrocardiogram electrode, comprising:

[0007] Step S1. Obtaining ECG signals of three leads I, II, and III;

[0008] Step S2: Determine the quality of the ECG signals of the three leads in step S1. When the signal quality of only two leads is poor, determine the ineffective contact time of electrode x:

[0009]

[0010] When the signal quality of the three leads is poor, determine the ineffective contact time of electrode x:

[0011]

[0012] Calculate the total ineffective contact time of electrode x:

[0013]

[0014] Step S3. Calculate the effective contact rate of electrode x according to the total duration of the ECG signal data and the total ineffective contact duration of electrode x:

[0015]

[0016] Among them, RA, LA, LL are the right hand electrode, x∈{RA,LA,LL}, the left hand electrode and the left leg electrode, L means the lead is valid, Indicates that the lead is invalid, T a is the total duration of ECG signal data.

[0017] Furthermore, in step S2, when the signal quality of the three leads is poor and it is impossible to determine whether the contact of the electrode x is good, the left and right boundaries of the effective contact rate of the electrode x are calculated in step S3:

[0018]

[0019] Then the range of the effective contact rate of electrode x is determined.

[0020] Furthermore, the chest lead signal is obtained and the effective contact rate of the electrode V is counted, including:

[0021] Step S4. When the quality of the signals of the three leads I, II, and III are all good and the quality of the current chest lead signal is poor, determine the ineffective contact time of the electrode V:

[0022]

[0023] When the quality of any of the three lead signals I, II, and III is poor and the quality of the current chest lead signal is poor, determine the ineffective contact time of electrode V:

[0024]

[0025] Calculate the total inactive contact time of electrode V:

[0026]

[0027] Step S5. Calculate the effective contact rate of electrode V according to the total duration of ECG signal data and the total ineffective contact duration of electrode V:

[0028]

[0029] Among them, V∈{V1,V2,V3,V4,V5,V6}.

[0030] Furthermore, in step S4, when any of the three lead signals I, II, and III is poor and the current chest lead signal is of poor quality, and it is impossible to determine whether the current V electrode is in good contact, the left and right boundaries of the effective contact rate of electrode V are calculated in step S5:

[0031]

[0032] The range of the effective contact rate of electrode V is then determined.

[0033] On the other hand, when the right boundary of the effective contact rate of the electrode x is lower than the first threshold, an electrode x wearing adjustment instruction is generated.

[0034] Further, when the right boundary of the effective contact rate of the electrode V is lower than the second threshold, an electrode V wearing adjustment instruction is generated.

[0035] Beneficial effects of the present invention:

[0036] Based on the characteristics of the three lead signals I, II, and III formed between the three electrodes RA, LA, and LL, the effectiveness of the electrode contact is determined by judging the quality of the lead signal, and the effectiveness of the electrode contact is calculated under long-term wearing conditions. Furthermore, the effectiveness of the chest lead electrode contact can be determined in the same way in combination with the signal quality of the limb leads, thereby evaluating the production process of the ECG electrodes and providing optimization guidance or providing users with a basis and instructions for wearing adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 A schematic diagram of the leads formed by the ECG electrode loop of the wearable device;

[0039] Figure 2 To test and calculate the effective boundary values ​​of electrode contact of three limb lead electrodes;

[0040] Figure 3 Schematic diagram of the ratio of the left and right boundaries of the electrode contact efficiency of the RA electrode produced by the first process

[0041] Figure 4 The left boundary comparison diagram of the contact efficiency of RA electrodes produced by the first process and the second process. DETAILED DESCRIPTION

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the directions or positions indicated by the terms "length", "width", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and should not be understood as limitations on the present technical solution.

[0043] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions; the terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0044] In the specification and claims of the present invention and the above-mentioned drawings, when an element is referred to as being "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it may be directly or indirectly located on the other element. For example, when an element is referred to as being "connected to" another element, it may be directly or indirectly connected to the other element.

[0045] In addition, reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] Example

[0047] As a comprehensive manifestation of cardiac electrical activity on the body surface, the human electrocardiogram (ECG) contains a wealth of physiological and pathological information reflecting cardiac rhythm and its electrical conduction, and has a very high application value in evaluating cardiac function and diagnosing heart disease. Nowadays, with the development of smart electronic devices, more and more wearable devices that can monitor human physiological signals have appeared on the market, and the acquisition of human electrocardiograms has gradually expanded from in-hospital examinations to out-of-hospital monitoring, among which wearable devices that monitor ECG are the majority.

[0048] ECG wearable devices usually include multi-lead wearable devices such as ECG vests and heart rate belts. Such devices are equipped with ECG electrodes, which are in direct contact with the human body surface to collect ECG signals. However, most of the ECG electrodes of wearable devices are dry electrodes, which have high requirements for electrode contact and adhesion. When wearable devices are worn, the ECG electrodes may not be in proper contact with the body surface, resulting in the collected ECG signals being of low quality or even completely interference signals. For multi-lead wearable devices, when the ECG signal quality does not meet the standards, it is of great significance to be able to promptly determine which specific electrode has unstable contact.

[0049] Most of the wearable devices in the prior art have a lead-off detection function. There are usually two ways to detect lead-off. One is to directly evaluate the quality of the ECG signal and whether the interference signal is strong, and then determine whether the current lead is in a detached / interfered state. Although this method can reflect the state of the lead, it cannot focus on the specific electrode with poor contact; the other method is on the hardware side, where a signal is generated inside the module / chip, output through a signal electrode, and then collected back by another signal electrode. If the signal can be collected back, it means that the lead is normal, otherwise the lead is detached. However, in order to ensure that the ECG signal with good signal quality is collected in a dry environment, the wearable device needs to increase the input impedance of the collection circuit. This method makes lead-off detection impossible to achieve, and this method still cannot locate the specific electrode with poor contact.

[0050] This embodiment provides a method for calculating the effective contact rate of ECG electrodes

[0051] Step S1. Obtaining ECG signals of three leads I, II, and III;

[0052] The ECG signal is collected by the user wearing a wearable device equipped with ECG electrodes, such as an ECG shirt, a heart rate belt, etc., and the wearable device has at least three electrodes, RA, LA, and LL. The ECG signal is transmitted to the host end mounted on the wearable device through the ECG electrodes and electrode wires. The host end has a storage function and stores the collected ECG signal in the local device. The ECG signal can also be transmitted to a remote end (such as a server) via wired or wireless means (such as Bluetooth, Wi-Fi, 4G, etc.), and visualized on other personal terminals (including mobile phones, PCs, etc.).

[0053] Step S2. Determine the quality of the ECG signals of the three leads in the step S1, upload the ECG signals collected by the wearable device to the server or other terminals (such as the mobile phone / ECG host device), and divide the ECG signals into ECG signals with good signal quality and ECG signals with poor signal quality according to time periods through the preset ECG signal analysis software. Methods for analyzing ECG signals and determining signal quality have been widely disclosed in the prior art, such as the method disclosed in the application document of CN20241088322263A, and will not be further elaborated in this embodiment.

[0054] like Figure 1 As shown, since the signals of leads I, II, and III are collected by forming a loop between the three electrodes RA, LA, and LL, when any electrode has poor contact, the signal quality of at least two leads will be poor. Therefore, when it is determined that only two leads have poor signal quality, the electrodes with poor contact can be directly determined. For example, when the signal quality of leads I and II is poor, the RA electrode has poor contact; when the signal quality of leads I and III is poor, the LA electrode has poor contact; when the signal quality of leads II and III is poor, the LL electrode has poor contact. It can be concluded that when only two leads have poor signal quality, the contact invalid time of the current electrode x is:

[0055]

[0056] Furthermore, when the signal quality of the three leads is poor, at least two electrodes are not in contact. At this time, if the current electrode x is in good contact, the contact invalid time is 0; if the current electrode x is in poor contact, the contact time is That is, when the signal quality of the three leads is poor, the contact invalid time of the current electrode x is:

[0057]

[0058] Furthermore, the total ineffective contact time of the current electrode x is calculated:

[0059]

[0060] Step S3. Calculate the effective contact rate of the current electrode x according to the total duration of the ECG signal data and the total ineffective contact duration of the current electrode x:

[0061]

[0062] In the above formula, RA, LA, and LL are the right hand electrode, left hand electrode, and left leg electrode, respectively. L indicates that the lead is valid. Indicates that the lead is invalid, T a is the total duration of ECG signal data.

[0063] It can be concluded that, in this embodiment, the signal quality of different leads can be used to determine which specific electrode has poor contact, and the total duration of the poor contact of the electrode can be calculated. Under long-term ECG monitoring, the contact effectiveness of the electrode can be further obtained.

[0064] The electrode contact efficiency can be used to provide guidance for the production process of the electrode. For example, the quality of the production process or electrode structure design improvement can be evaluated based on the electrode efficiency obtained from the test before and after the production process / electrode structure design improvement. The production process or electrode structure design here includes but is not limited to the selection of electrode materials, the size of the electrode area, etc. On the other hand, the electrode contact efficiency can also prompt and guide the user's usage habits. For example, if the effective contact rate of electrode x is low within a certain period of time, the user will be prompted to adjust the wearing, and feedback will be given when the effective contact rate of the electrode increases / decreases.

[0065] In the above embodiment, when only two lead signals have poor quality, the electrode x with poor contact is determined, and the invalid contact time is That is also certain.

[0066] When the quality of the three lead signals is poor, it is impossible to determine the specific electrode with poor contact under the current conditions. In some embodiments, the hardware circuit of the wearable device can give an identification or signal of poor electrode contact. When the hardware circuit can detect the specific electrode with poor contact, the invalid contact time at this time is also determined; then the total ineffective contact time of electrode x can also be determined, which is

[0067]

[0068] However, in most cases, the hardware circuit of the wearable device cannot give an indication or signal of poor electrode contact. Therefore, when the quality of the three lead signals is poor, it is impossible to determine whether the poor quality of the lead signal is caused by poor contact of electrode x. At this time, the invalid contact time of electrode x cannot be determined, but the invalid contact time of electrode x can be estimated. If electrode x is in good contact, then the invalid contact time of electrode x is is 0; if electrode x has poor contact, then the ineffective contact time of electrode x is for That is, when the quality of the three lead signals is poor and it is not possible to determine whether it is caused by poor contact of electrode x, the ineffective contact time of electrode x is The left boundary represents the whole time period when the quality of the three lead signals is poor, and the electrode x is in good contact. The right boundary represents the whole time period when the quality of the three lead signals is poor, and the contact of the electrode x is poor. Therefore, the total ineffective contact time of the electrode x is in the range of The range of the effective contact rate of electrode x can be further determined:

[0069]

[0070] To facilitate understanding of the above embodiment, take RA electrode as an example:

[0071] like Figure 1 As shown in the figure, when it is detected that the quality of the I and II lead signals is poor and the quality of the III lead signal is good, it can be determined that the electrode RA has poor contact. At this time, the invalid contact time of the electrode RA is:

[0072]

[0073] When the signal quality of the three leads I, II, and III is poor, at least two electrodes have poor contact. However, when the hardware circuit cannot indicate whether RA has poor contact, it is impossible to determine whether there is an RA electrode. Therefore, the invalid contact time of electrode RA is:

[0074]

[0075] Furthermore, according to the above two situations, the total ineffective contact time of the electrode RA is calculated:

[0076]

[0077] Total contact invalid time T RA The range is

[0078] Furthermore, the effective contact rate of the electrode RA is calculated according to the total duration of the ECG signal data and the total ineffective contact duration of the electrode RA:

[0079]

[0080] According to T RA , calculate the left and right boundaries of the effective contact rate of the electrode RA, and further determine E RA Range:

[0081]

[0082] As an optional embodiment, some wearable devices, such as electrocardiograph clothing, include not only RA, LA, and LL electrodes, but also V electrodes for collecting chest lead signals. Therefore, based on the above embodiment, the effective contact rate of the chest lead electrodes can be further calculated.

[0083] The chest lead signal usually uses the V (where V∈{V1,V2,V3,V4,V5,V6}) electrode as the positive electrode and the central potential terminal as the negative electrode to form a loop to collect ECG signals. The central potential terminal, also known as the Wilson central terminal, is generated by connecting the RA, LA, and LL electrodes through a resistor network and represents the average voltage of the body. Due to the characteristic that the negative electrode of the chest lead is the central potential terminal, the quality of the chest lead signal depends to a certain extent on the contact degree of the limb electrodes (RA, LA, LL).

[0084] Therefore, based on the signal quality of the limb leads, in step S4, when the signals of the three leads I, II, and III are all good, it can be determined that the RA, LA, and LL electrodes are in good contact, and the central potential end is also accurate. In the current case, the chest lead signal quality is poor, which can only be caused by the poor contact of the V electrode. At this time, the invalid contact time of the electrode V is:

[0085]

[0086] When any of the three lead signals I, II, and III is poor, at least one of the three electrodes RA, LA, and LL has poor contact, and the central potential terminal must be inaccurate. At this time, regardless of whether the V electrode has good contact, the chest lead signal must be inaccurate, that is, the contact degree of the V electrode cannot be directly determined by the quality of the chest lead signal. The V electrode may have good contact or poor contact. At this time, the invalid contact time of the V electrode is:

[0087]

[0088] The total contact ineffective time of electrode V is:

[0089]

[0090] Further, step S5. calculates the effective contact rate of electrode V according to the total duration of the ECG signal data and the total ineffective contact duration of the electrode V:

[0091]

[0092] Among them, V∈{V1,V2,V3,V4,V5,V6}.

[0093] Preferably, according to the above embodiment, after calculating the left and right boundaries of the effective contact rate of the electrode V, the effective contact rate range of the electrode V is obtained:

[0094]

[0095] In the following embodiments, some uses of a method for calculating the effective contact rate of ECG electrodes according to the present invention are listed.

[0096] The effective contact rate range of the electrode is continuously counted during the user's wearing cycle to evaluate the contact status of the electrode. During the user's wearing process, if the right boundary of the effective contact rate of electrode x is lower than the first threshold, T X 1 If the electrode x is worn for too long and the effective contact rate of the electrode is too low, the electrode x is not firmly attached to the user's body. At this time, an electrode x wearing adjustment instruction is generated, for example: ask the user to adjust the wearing of the RA electrode. For products with integrated electrodes and wearable devices, the fabric near the electrode can be adjusted; for products with independent electrodes, the electrode can be removed from the wearable device and reinstalled.

[0097] Furthermore, if the right boundary of the effective contact rate of the electrode V is lower than the second threshold value, T V 1 If the electrode is not in contact with the user for too long, the effective contact rate of the electrode is too low, and the electrode V is not firmly attached to the user's body. At this time, an electrode V wearing adjustment instruction is generated, for example: ask the user to adjust the wearing of electrode V1. For products with integrated electrodes and wearable devices, the fabric near the electrode can be adjusted; for products with independent electrodes, the electrode can be removed from the wearable device and reinstalled.

[0098] The first threshold and the second threshold described in the embodiment are both empirical thresholds. Those skilled in the art can adjust the thresholds according to the sensitivity and specificity of the effective contact rate of the electrode, and are not specifically limited in this embodiment. Figure 2 Shown are the means of the left and right boundaries of contact effectiveness for the three limb electrodes during the day and night.

[0099] On the other hand, the design and production process of the electrode can also be evaluated and guided according to the effective contact rate of the electrode. The left and right boundaries of the effective contact rate of the electrode to be tested are divided into 10 segments from 0-1, and the proportion of the electrode produced in different batches before and after the process improvement in each segment is statistically analyzed. The higher the proportion of the left and right boundaries in the high segment, the higher the electrode contact efficiency. Figure 3 The figure shows the proportion of the left and right boundaries of the RA electrodes of the same batch in the first process. It can be seen that the right boundary of the RA electrodes of this batch has a higher proportion in the high segment, while the left boundary is more evenly distributed.

[0100] like Figure 4The figure shows the statistical graph of the left boundary of the effective contact rate of the RA electrode before and after the two processes. It can be concluded that the proportion of the left boundary above 0.5 in the second process is significantly higher than that in the first process, and the proportion of the left boundary below 0.5 in the second process is significantly lower than that in the first process. The effective contact rate of the electrode has been significantly improved.

[0101] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

Claims

1. A method for calculating the effective contact rate of an electrocardiogram electrode, comprising: Step S1. Obtaining ECG signals of three leads I, II, and III; Step S2: Determine the quality of the ECG signals of the three leads in step S1. When the signal quality of only two leads is poor, determine the ineffective contact time of electrode x: When the signal quality of the three leads is poor, determine the ineffective contact time of electrode x: Calculate the total ineffective contact time of electrode x: Step S3. Calculate the effective contact rate of electrode x according to the total duration of the ECG signal data and the total ineffective contact duration of electrode x: Among them, RA, LA, LL are the right hand electrode, x∈{RA,LA,LL}, the left hand electrode and the left leg electrode, L means the lead is valid, Indicates that the lead is invalid, T a is the total duration of ECG signal data.

2. The method for calculating the effective contact rate of ECG electrodes according to claim 1, characterized in that: When the signal quality of the three leads is poor and it is impossible to determine whether the contact of the lower electrode x is good in step S2, the left and right boundaries of the effective contact rate of electrode x are calculated in step S3: Then the range of the effective contact rate of electrode x is determined.

3. The method for calculating the effective contact rate of ECG electrodes according to claim 1, characterized in that: Obtain chest lead signals and count the effective contact rate of electrode V, including: Step S4. When the quality of the signals of the three leads I, II, and III are all good and the quality of the current chest lead signal is poor, determine the ineffective contact time of the electrode V: When the quality of any of the three lead signals I, II, and III is poor and the quality of the current chest lead signal is poor, determine the ineffective contact time of electrode V: Calculate the total inactive contact time of electrode V: Step S5. Calculate the effective contact rate of electrode V according to the total duration of ECG signal data and the total ineffective contact duration of electrode V: Among them, V∈{V1,V2,V3,V4,V5,V6}.

4. The method for calculating the effective contact rate of ECG electrodes according to claim 3, characterized in that: In step S4, when any of the three lead signals I, II, and III is poor and the quality of the current chest lead signal is poor, and it is impossible to determine whether the current V electrode is in good contact, the left and right boundaries of the effective contact rate of electrode V are calculated in step S5: Then the range of the effective contact rate of electrode V is determined.

5. The use of the method for calculating the effective contact rate of ECG electrodes according to claim 2, characterized in that: When the right boundary of the effective contact rate of the electrode x is lower than the first threshold, an electrode x wearing adjustment instruction is generated.

6. Use of the method for calculating the effective contact rate of ECG electrodes according to claim 4, characterized in that: When the right boundary of the effective contact rate of the electrode V is lower than the second threshold, an electrode V wearing adjustment instruction is generated.

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