Myocardial ischemia detection device and myocardial ischemia detection method

Abstract

A myocardial ischemia detection device and a myocardial ischemia detection method, wherein the myocardial ischemia detection device includes a measuring unit and a processing unit. The myocardial ischemia detection method includes a measuring step, a feature extraction step, and a first analysis step. The measuring step obtains multiple electrocardiogram (ECG) signals of a human body by means of the measuring unit. The measurement positions of at least part of the ECG signals correspond to the left chest of the human body. The feature extraction step extracts the QT interval of each ECG signal by means of the processing unit, and calculates multiple feature values corresponding to multiple points of the human body. The first analysis step is to compare the point positions corresponding to at least one of the lowest feature values to detect the location of myocardial ischemia. Compared with the existing analysis method based on the waveform changes of the ST segment, the QT interval is less affected by noise and baseline offset, and can avoid evaluation errors.

Description

Technical Field

[0001] The present invention relates to the field of electrocardiographic signal analysis, and in particular to a myocardial ischemia detection device and a myocardial ischemia detection method. Background Art

[0002] The three coronary arteries that maintain blood supply to the heart are the right coronary artery (RCA), the left anterior descending coronary artery (LAD), and the left circumflex coronary artery (LCX). Medical treatment varies depending on the type of arterial blockage. The American Heart Association stipulates that patients with myocardial infarction should undergo cardiac catheterization within 90 minutes of hospitalization to reduce the duration of myocardial ischemia and mortality. Therefore, assessing the presence and location of myocardial ischemia as quickly as possible is crucial.

[0003] The location of acute myocardial ischemia is typically assessed using a 12-lead electrocardiogram (ECG). This assessment requires comprehensive evaluation based on ST segment rise and fall waveform changes in different groups of leads, including the anterior chest leads (V1-V6), inferior leads (II, III, aVF), and lateral / apical leads (I, aVL, V5, V6). Because ST segment changes are often not obvious in the early stages of myocardial ischemia, shortening the assessment time is practically challenging.

[0004] In addition, the waveform changes of the ST segment of the electrocardiogram are easily affected by chest wall impedance, noise and baseline offset, and are therefore prone to assessment errors. Summary of the Invention

[0005] Therefore, an object of the present invention is to provide a myocardial ischemia detection device that overcomes at least one of the shortcomings of the prior art.

[0006] Therefore, the myocardial ischemia detection device of the present invention is suitable for use in a human body. The myocardial ischemia detection device includes a measuring unit and a processing unit. The measuring unit includes four limb conduction electrodes and multiple chest electrodes. The limb conduction electrodes and the chest electrodes are suitable for obtaining multiple electrocardiogram (ECG) signals from the human body. The measurement positions of at least some of the chest electrodes correspond to the left chest of the human body. The processing unit is signal-connected to the measuring unit and can receive the ECG signals. The processing unit can extract the QT interval of the ECG signals and calculate multiple characteristic values corresponding to multiple points on the left chest of the human body based on the QT interval. The processing unit then detects the location of myocardial ischemia in the human body based on the ECG signal measurement position corresponding to at least one of the lowest characteristic values.

[0007] The myocardial ischemia detection device of the present invention further comprises a database unit, which stores comparison information. The processing unit can compare the comparison information with the high and low distribution states of the characteristic values to detect the scope of myocardial ischemia.

[0008] In the myocardial ischemia detection device of the present invention, the chest electrodes of the measurement unit are suitable for obtaining at least 16 electrocardiogram signals of a reference plane of the human body, wherein the reference plane is defined by the right sternal margin of the human body, a horizontal line at the first intercostal space corresponding to the height of the right sternal margin, the left axillary midline, and a horizontal line at the eighth rib corresponding to the height of the right sternal margin.

[0009] In the myocardial ischemia detection device of the present invention, the processing unit can also capture the RR interval of the electrocardiogram signal. The processing unit calculates the QTc interval of the point using the QT interval and the RR interval to serve as the characteristic value.

[0010] The myocardial ischemia detection device of the present invention further includes an output unit, and the processing unit can image the numerical difference of the characteristic value and the corresponding distribution position on the output unit in different color levels.

[0011] In the myocardial ischemia detection device of the present invention, the processing unit can also calculate discrete parameters using an evaluation parameter algorithm, and evaluate the severity of the overall myocardial ischemia of the human body based on the discrete parameters. The evaluation parameter algorithm is: Among them, SI QTc is the discrete parameter, S is the total number of points, (QTc) k is the QTc interval of a specific point, n is the number of points closest to the specific point corresponding to the body position, (QTc) i The QTc interval of one of the points closest to the point corresponding to the human body position.

[0012] In the myocardial ischemia detection device of the present invention, the processing unit can also calculate the difference value QTcD between the maximum and minimum values of the QTc interval at the point, and evaluate the severity of the overall myocardial ischemia of the human body based on the difference value between the maximum and minimum values of the QTc interval.

[0013] Another object of the present invention is to provide a method for detecting myocardial ischemia that overcomes at least one of the shortcomings of the prior art.

[0014] Therefore, the myocardial ischemia detection method of the present invention includes a measurement step, a feature extraction step, and a first analysis step. The measurement step obtains multiple electrocardiogram (ECG) signals of a human body, and the measurement positions of at least some of the ECG signals correspond to the left chest of the human body. The feature extraction step uses a processing unit to extract the QT interval of each ECG signal and calculates multiple feature values corresponding to multiple points on the left chest of the human body based on the QT interval. The first analysis step compares the point corresponding to at least one of the lowest feature values with the position on the left chest of the human body to detect the location of myocardial ischemia.

[0015] In the myocardial ischemia detection method of the present invention, the first analysis step further includes comparing the high and low distribution states of the characteristic values with comparison information to detect the scope of the myocardial ischemia.

[0016] In the myocardial ischemia detection method of the present invention, the measurement step is to obtain the electrocardiogram signal of the reference plane of the human body, where the reference plane is defined by the right sternal margin of the human body, a horizontal line at the first intercostal space corresponding to the height of the right sternal margin, the left axillary midline, and a horizontal line at the eighth rib corresponding to the height of the right sternal margin.

[0017] In the myocardial ischemia detection method of the present invention, the feature extraction step further extracts the RR interval of the electrocardiogram signal, and calculates the QTc interval of the point using the QT interval and the RR interval to serve as the feature value.

[0018] In the myocardial ischemia detection method of the present invention, the first analysis step is to generate an image according to the characteristic value corresponding to the position of the left chest of the human body and using different color levels to represent the high and low characteristics of the characteristic value, and detect the scope of myocardial ischemia by comparing the image with the comparison information.

[0019] In the myocardial ischemia detection method of the present invention, the characteristic value calculated in the feature extraction step is the QTc interval corresponding to the point calculated based on the electrocardiogram signal. The myocardial ischemia detection method further includes a second analysis step, wherein the second analysis step calculates discrete parameters using an evaluation parameter algorithm and evaluates the severity of the overall myocardial ischemia of the human body based on the discrete parameters. The evaluation parameter algorithm is Among them, SI QTc is the discrete parameter, S is the total number of points, (QTc) k is the QTc interval of a specific point, n is the number of points closest to the point corresponding to the body position, (QTc) i is the QTc interval of one of the points closest to the point corresponding to the human body position.

[0020] In the myocardial ischemia detection method of the present invention, the feature value calculated in the feature extraction step is the QTc interval corresponding to the point based on the electrocardiogram signal. The myocardial ischemia detection method further includes a second analysis step, which calculates the difference between the maximum and minimum values of the QTc interval at the point, and assesses the severity of the overall myocardial ischemia in the human body based on the difference between the maximum and minimum values of the QTc interval (QTcD).

[0021] The beneficial effect of the present invention is that the characteristic value is calculated by the QT interval to detect the location of myocardial ischemia in the human body. Compared with the existing analysis method based on ST segment waveform changes, the QT interval is less affected by chest wall impedance, noise and baseline offset, thereby avoiding evaluation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features and effects of the present invention will be more clearly seen in the following embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 is a system block diagram of an embodiment of a myocardial ischemia detection device of the present invention;

[0024] Figure 2 is a schematic diagram illustrating that a reference plane of a human body corresponding to the multiple electrocardiogram signals obtained in the embodiment is defined by the right sternal margin of the human body, a horizontal line at the first intercostal space corresponding to the height of the right sternal margin, the left axillary midline, and a horizontal line at the eighth rib corresponding to the height of the right sternal margin;

[0025] Figure 3 is a schematic diagram illustrating the placement of 16 chest electrodes in the embodiment;

[0026] Figure 4 is a schematic diagram of a comparison information stored in a database unit of the embodiment;

[0027] Figure 5 is a flow chart illustrating the process of a myocardial ischemia detection method using the embodiment;

[0028] Figure 6 Schematic diagram illustrating the acquisition of 16 ECG signals from the left chest of a patient with left circumflex coronary artery (LCX) stenosis. Two-dimensional interpolation is performed to obtain 24 characteristic values at these points. Different color scales are used to represent the characteristic values of the ECG signals, and the resulting image is output to an output unit.

[0029] Figure 7Another schematic diagram illustrates obtaining 16 ECG signals from the left chest of a patient with right coronary artery (RCA) stenosis, obtaining 24 characteristic values at each point through two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0030] Figure 8 Another schematic diagram illustrates obtaining 16 electrocardiogram (ECG) signals from the left chest of a patient with left anterior descending coronary artery (LAD) stenosis, obtaining characteristic values at 24 points through two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0031] Figure 9 Another schematic diagram illustrates obtaining 16 ECG signals from the left chest of a patient with three coronary artery stenosis (3VD), obtaining 24 characteristic values at each point through two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0032] Figure 10 is similar Figure 3 Schematic diagram illustrating a modified arrangement in which the number of pre-chest electrodes in the embodiment is changed to 24;

[0033] Figure 11 is similar Figure 6 Schematic diagram illustrating obtaining 24 electrocardiogram (ECG) signals from the left chest of a patient with left circumflex coronary artery (LCX) stenosis, obtaining 36 characteristic values at each point by two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0034] Figure 12 is similar Figure 7 Schematic diagram illustrating obtaining 24 electrocardiogram (ECG) signals from the left chest of a patient with right coronary artery (RCA) stenosis, obtaining 36 characteristic values at each point by two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0035] Figure 13 is similar Figure 8 Schematic diagram illustrating obtaining 24 electrocardiogram (ECG) signals from the left chest of a patient with left anterior descending coronary artery (LAD) stenosis, obtaining 36 characteristic values at each point by two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low characteristic values of the ECG signals;

[0036] Figure 14 is similar Figure 9Schematic diagram illustrating obtaining 24 ECG signals from the left chest of a patient with three coronary artery stenosis (3VD), obtaining 36 feature values at each point by two-dimensional interpolation, and outputting an image to the output unit using different color scales to represent the high and low feature values of the ECG signals;

[0037] Figure 15 Is another similar Figure 3 Schematic diagram illustrating another variation of the configuration in which the number of pre-chest electrodes in the embodiment is changed to 24;

[0038] Figure 16 It's another similar Figure 3 Schematic diagram illustrating a variation of the configuration in which the number of chest electrodes is changed to 36 in the embodiment. DETAILED DESCRIPTION

[0039] See Figures 1 to 4 An embodiment of the myocardial ischemia detection device of the present invention is applicable to a human body 1. The human body includes a reference plane 100 corresponding to the left chest. The reference plane 100 is defined by a right sternal margin 11 of the human body 1, a horizontal line 12 located in the first intercostal space and corresponding to the height of the right sternal margin 11, a left axillary midline 13, and a horizontal line 14 corresponding to the eighth rib and corresponding to the height of the right sternal margin 11.

[0040] The myocardial ischemia detection device includes a measuring unit 2, a processing unit 3, a database unit 4, an input unit 5, an output unit 6, and a wearable unit 7. The processing unit 3 is signal-connected to the measuring unit 2, the database unit 4, the input unit 5, and the output unit 6.

[0041] The input unit 5 can be input with an operation instruction, a mode selection instruction, and an output instruction.

[0042] The measurement unit 2 includes four limb electrodes 26 and a plurality of spaced-apart chest electrodes 21 adapted for placement and arrangement on the reference surface 100. The measurement unit 2 can, in accordance with the operating instructions, cause the limb electrodes 26 and the chest electrodes 21 to acquire multiple ECG signals from the human body 1. The measurement positions of at least some of the chest electrodes 21 correspond to the left chest of the human body 1. Each ECG signal comprises a P wave, a Q wave, an R wave, an S wave, and a T wave.

[0043] It should be noted that, in order to clearly reveal the location of the chest electrodes 21 and the wearable unit 7 corresponding to the human body 1, Figure 3 and subsequent Figure 10 、 Figure 15 and Figure 16In FIG, the chest electrodes 21 are drawn with imaginary lines, and Figure 2 The wearable unit 7 is drawn with a dotted line.

[0044] The number of the chest electrodes 21 may be more than 16, and a corresponding number of ECG signals of the reference surface 100 of the human body 1 are obtained through the chest electrodes 21 , and the ECG signals are arranged at corresponding measurement positions on the reference surface 100 .

[0045] In terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, at least 2 chest electrodes 21 among the chest electrodes 21 correspond to the right sternal margin 11, at least 3 chest electrodes 21 correspond to the left sternal margin 111, at least 3 chest electrodes 21 correspond to the midline 113 between the left sternal margin 111 and a left clavicle midline 112, at least 4 chest electrodes 21 correspond to the left clavicle midline 112, at least 2 chest electrodes 21 correspond to a left axillary anterior edge line 114, and at least 2 chest electrodes 21 correspond to the left axillary midline 13.

[0046] In terms of the lateral position of the chest electrodes 21 corresponding to the human body 1, at least 3 of the chest electrodes 21 correspond to a third intercostal space corresponding to the height of the right sternal margin 11, at least 5 chest electrodes 21 correspond to a fourth intercostal space corresponding to the height of the right sternal margin 11, at least 4 chest electrodes 21 correspond to a fifth intercostal space corresponding to the height of the right sternal margin 11, and at least 1 chest electrode 21 corresponds to a sixth intercostal space corresponding to the height of the right sternal margin 11, and the height of at least 3 of the chest electrodes 21 corresponding to the midline 113 between the left sternal margin 111 and the left clavicle midline 112 is between the third intercostal space and a sixth rib.

[0047] In this embodiment, the number of the chest electrodes 21 is 16. In terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, two of the chest electrodes 21 correspond to the right sternum edge 11, three chest electrodes 21 correspond to the left sternum edge 111, three chest electrodes 21 correspond to the midline 113 between the left sternum edge 111 and the left clavicle midline 112, four chest electrodes 21 correspond to the left clavicle midline 112, two chest electrodes 21 correspond to the left axillary front edge line 114, and two chest electrodes 21 correspond to the left axillary midline 13. With respect to the lateral position of the human body 1, three of the pre-chest electrodes 21 correspond to the third intercostal space and correspond to the height of the right sternal margin 11, five pre-chest electrodes 21 correspond to the fourth intercostal space and correspond to the height of the right sternal margin 11, four pre-chest electrodes 21 correspond to the fifth intercostal space and correspond to the height of the right sternal margin 11, four pre-chest electrodes 21 correspond to the sixth intercostal space and correspond to the height of the right sternal margin 11, and the three pre-chest electrodes 21 corresponding to the midline 113 between the left sternal margin 111 and the left clavicle midline 112 correspond to the heights of a fourth rib, a fifth rib, and the sixth rib, respectively.

[0048] In this embodiment, the measurement unit 2 further includes a signal buffer 22 electrically connected to the chest electrodes 21, a signal amplifier 23 electrically connected to the signal buffer 22, a filter 24 electrically connected to the signal amplifier 23, and a signal converter 25 electrically connected to the filter 24. The signal buffer 22 can provide a sufficiently large input impedance to couple the ECG signal to the signal amplifier 23. The signal amplifier 23 further amplifies the ECG signal and inputs it to the filter 24. The filter 24 can remove noise and power signal interference from the ECG signal. The signal converter 25 can convert the ECG signal into a digital signal for subsequent analysis by the processing unit 3.

[0049] The database unit 4 stores a comparison information 41. The comparison information 41 is divided into three comparison regions 411 from the upper right to the lower left. The comparison regions 411 represent the left circumflex coronary artery (LCX), the left anterior descending coronary artery (LAD), and the right coronary artery (RCA) from the upper right to the lower left.

[0050] The processing unit 3 is signal-connected to the measurement unit 2 and is capable of receiving the ECG signal. The processing unit 3 is capable of extracting the QT interval and RR interval of the ECG signal and, based on the QT interval and RR interval, calculating characteristic values corresponding to a plurality of points on the reference plane 100 on the left chest of the human body 1. The characteristic values are the QTc intervals corresponding to the points calculated based on the ECG signal.

[0051] The characteristic value is calculated by calculating the QTc interval of the electrocardiogram signal using the QT interval and the RR interval, and then deciding whether to expand the calculation of the QTc interval of more points using two-dimensional interpolation calculation depending on the number and needs of the pre-chest electrodes 21, and using the QTc interval calculated from the electrocardiogram signal and the expanded QTc interval as the characteristic value respectively.

[0052] In this embodiment, the processing unit 3 captures the QT intervals and RR intervals of the 16 ECG signals, and calculates 16 QTc intervals using the QT intervals and RR intervals, respectively. These intervals are then expanded to 24 QTc intervals using two-dimensional interpolation. The calculation formula for calculating the QTc interval of the ECG signal using the QT intervals and RR intervals is:

[0053] Wherein, QTc is the QTc interval, QT is the QT interval (in milliseconds), and RR is the RR interval (in seconds).

[0054] The processing unit 3 can detect the location of myocardial ischemia in the human body 1 based on the electrocardiogram signal measurement position corresponding to at least one of the lowest eigenvalues, and can compare the high and low distribution states of the eigenvalues with the comparison information 41 to detect the range of myocardial ischemia, and can output the detection results of the myocardial ischemia location and the range of myocardial ischemia to the output unit 6 according to the output instruction.

[0055] The processing unit 3 can also display the characteristic value on the output unit 6 according to the output instruction, and can also image the numerical difference of the characteristic value and the corresponding distribution position on the output unit 6 in different color levels. The method of the processing unit 3 imaging the numerical difference of the characteristic value and the corresponding distribution position in different color levels is similar to the layered color method and terrain color shading method used in cartography, that is, different colors or shades are used to represent different characteristic values, so that a user can easily and conveniently understand the high and low distribution of the characteristic value, thereby facilitating the assessment of the location and range of myocardial ischemia.

[0056] In addition, the processing unit 3 can calculate and evaluate the severity of global myocardial ischemia in at least one of a first evaluation mode and a second evaluation mode according to the mode selection instruction of the input unit 5, and output the evaluation result to the output unit 6 according to the output instruction.

[0057] The first evaluation mode is to calculate a discrete parameter (SI) using an evaluation parameter algorithm. QTc ), and evaluate the severity of the overall myocardial ischemia of the human body 1 based on the discrete parameters, and the evaluation parameter algorithm is:

[0058] Among them, SI QTc is the discrete parameter, S is the total number of points, (QTc) k is the QTc interval of a specific point, n is the number of points closest to the specific point corresponding to the position of the human body 1, (QTc) i is the QTc interval of one of the points closest to the specific point corresponding to the position of the human body 1. QTc The larger the value is, the more severe the overall myocardial ischemia of the human body 1 is.

[0059] The second assessment mode calculates the difference (QTcD) between the maximum and minimum QTc intervals at the points, and assesses the severity of overall myocardial ischemia in the subject 1 based on the difference (QTcD). A greater difference (QTcD) between the maximum and minimum QTc intervals indicates greater severity of overall myocardial ischemia in the subject 1.

[0060] The wearable unit 7 can be worn by the person 1, and the chest electrodes 21 of the measurement unit 2 are disposed on the wearable unit 7. When the person 1 wears the wearable unit 7, the chest electrodes 21 correspond to predetermined positions on the reference surface 100. In this embodiment, the wearable unit 7 is a vest-like outer garment.

[0061] See Figures 1 to 4 In actual application, a myocardial ischemia detection method can be used for detection, and the myocardial ischemia detection method includes the following steps S1 to S5.

[0062] Step S1 , command input step: input the operation command, the mode selection command, and the output command into the input unit 5 .

[0063] Step S2, measuring step: obtaining the electrocardiogram signal of the human body 1.

[0064] Wherein, the measurement position of at least part of the electrocardiogram signal corresponds to the left chest of the human body 1 .

[0065] The measurement step is to obtain the ECG signal of a reference plane 100 of the human body 1. The reference plane 100 is defined by the right sternal margin 11 of the human body 1, a horizontal line 12 of the first intercostal space corresponding to the height of the right sternal margin 11, the left axillary midline 13, and a horizontal line 14 of the eighth rib corresponding to the height of the right sternal margin 11.

[0066] Step S3, feature extraction step: The processing unit 3 extracts the QT interval and the RR interval of each electrocardiogram signal, and calculates the feature values of multiple points corresponding to the left chest of the human body 1 according to the QT interval and the RR interval.

[0067] In this embodiment, the feature value calculated in the feature extraction step is the QTc interval corresponding to the point calculated based on the electrocardiogram signal.

[0068] Step S4, first analysis step: compare the point corresponding to at least one of the lowest eigenvalues with the position of the left chest of the human body to detect the location of myocardial ischemia, and compare the high and low distribution states of the eigenvalues with the comparison information 41 to detect the range of myocardial ischemia.

[0069] The first analysis step may be automatically processed by the processing unit 3 to detect the location and range of myocardial ischemia in the human body 1, and then output the detection results to the output unit 6 according to the output instruction. The first analysis step may also be performed by the processing unit 3 first generating a corresponding image on the output unit 6 according to the output instruction by converting the characteristic values corresponding to the location of the left chest of the human body 1 and using different color levels to represent the high and low characteristics of the characteristic values, and then having the user visually evaluate the high and low distribution of the characteristic values, and then detecting the location and range of myocardial ischemia by comparing the image with the comparison information 41.

[0070] Step S5, second analysis step: the processing unit 3 calculates and evaluates the severity of the overall myocardial ischemia of the human body 1 using at least one of the first evaluation mode and the second evaluation mode according to the mode selection instruction of the input unit 5, and outputs the evaluation result to the output unit 6 according to the output instruction.

[0071] Through the above steps S1 to S5 , the location of myocardial ischemia, the range of myocardial ischemia, and the overall severity of myocardial ischemia of the human body 1 can be evaluated.

[0072] See Table 1 and Figure 4 、 Figure 6 For example, Table 1 is a QTc interval distribution table, which is obtained by using the myocardial ischemia detection device and the myocardial ischemia detection method, using 16 pre-chest electrodes 21 to measure 16 electrocardiogram signals from the left chest of a patient with left circumflex coronary artery (LCX) stenosis. After calculating the QTc intervals of the electrocardiogram signals, a QTc interval distribution table of 24 points (including the aforementioned 16 QTc intervals calculated from the electrocardiogram signals) is obtained by two-dimensional interpolation. The values in the table represent the QTc interval of each point and are arranged according to the corresponding electrocardiogram measurement position and the point position corresponding to the two-dimensional interpolation. Figure 6 The image outputted to the output unit 6 is represented by different color levels to indicate the high and low characteristics.

[0073] From Table 1 and Figure 6 It can be seen that the lowest QTc interval corresponds to the upper right corner of the figure. Figure 4 The comparison information 41 can be used to assess that the patient's myocardial ischemia is located in the blood supply area of the left circumflex artery (LCX) of the left coronary artery.

[0074] It should be noted that the QTc intervals at the above-mentioned 24 points can also be obtained by obtaining ECG signals through 17, 18 or other numbers of the pre-chest electrodes 21, and then obtaining the QTc intervals at the 24 points through a two-dimensional interpolation calculation program, or can also be directly calculated through the ECG signals obtained by the 24 pre-chest electrodes 21 without going through a two-dimensional interpolation calculation program, and the points of the QTc interval distribution table can also be other numbers, for example, after obtaining ECG signals through the 24 pre-chest electrodes 21, the QTc interval distribution table can be expanded to 36 points through two-dimensional interpolation calculation.

[0075] Table 1 shows an example of the QTc interval in a patient with left circumflex artery (LCX) stenosis of the left coronary artery:

[0076] 426 409 400 392 377 368 426 405 396 383 362 358 411 396 388 366 451 451 411 404 386 366 409 430

[0077] See Table 2 and Figure 4 、 Figure 7 Table 2 shows a QTc interval distribution table of 24 points (including the aforementioned 16 QTc intervals calculated from the electrocardiogram signals) obtained by using the myocardial ischemia detection device and the myocardial ischemia detection method, using 16 pre-chest electrodes 21 to measure the QTc intervals of the 16 electrocardiogram signals obtained from the left chest of a patient with right coronary artery (RCA) stenosis. Figure 7 The corresponding image is displayed on the output unit 6.

[0078] From Table 2 and Figure 7 It can be seen that the lowest QTc interval corresponds to the left side of the figure. Figure 4 The comparison information 41 can be used to assess that the patient's myocardial ischemia is located in the blood supply area of the right coronary artery (RCA).

[0079] Table 2 shows an example of the QTc interval in a patient with right coronary artery (RCA) stenosis:

[0080] 417 428 356 390 400 404 428 348 390 394 409 409 394 360 398 394 409 413 394 377 392 402 405 409

[0081] See Table 3 and Figure 4 、 Figure 8 Table 3 shows a QTc interval distribution table of 24 points (including the aforementioned 16 QTc intervals calculated from the electrocardiogram signals) obtained by using the myocardial ischemia detection device and the myocardial ischemia detection method, using 16 precordial electrodes 21 to measure the QTc intervals of the 16 electrocardiogram signals obtained from the left chest of a patient with left anterior descending coronary artery (LAD) stenosis. Figure 8 The corresponding image is displayed on the output unit 6.

[0082] From Table 3 and Figure 8 It can be seen that the lowest QTc interval corresponds to the upper middle area in the figure. Figure 4 The comparison information 41 can be used to assess that the patient's myocardial ischemia is located in the blood supply area of the left anterior descending artery (LAD) of the left coronary artery.

[0083] Table 3 shows an example of the QTc interval in a patient with left anterior descending artery (LAD) stenosis:

[0084] 415 374 378 378 388 393 415 399 382 382 399 399 403 390 403 403 403 399 403 397 402 407 405 402

[0085] See Table 4 and Figure 4 、 Figure 9 Table 4 shows a QTc interval distribution table of 24 points (including the aforementioned 16 QTc intervals calculated from the electrocardiogram signals) obtained by using the myocardial ischemia detection device and the myocardial ischemia detection method, using 16 precordial electrodes 21 to measure the QTc intervals of the left chest of a patient with three coronary artery stenosis (3VD). Figure 9 The corresponding image is displayed on the output unit 6.

[0086] From Table 4 and Figure 9It can be seen that the lowest QTc interval corresponds to the upper left area in the figure, but according to Figure 9 The areas showing a low QTc interval include the upper left and upper right areas of the figure. Figure 4 According to the comparison information 41 , the area with a low QTc interval covers the three comparison areas 411 of the comparison information 41 , so it can be assessed that the range of the patient's myocardial ischemia covers the blood supply areas of three coronary arteries.

[0087] Table 4 shows an example of the QTc interval for a patient with three coronary artery stenosis (3VD):

[0088] 376 364 442 417 411 400 364 458 430 417 405 389 401 438 422 417 422 422 401 419 423 430 426 424

[0089] Tables 1 to 4 above and Figures 6 to 9 Myocardial ischemia detection is performed using 16 ECG signals, but is not limited thereto. The myocardial ischemia detection device and the myocardial ischemia detection method can also be applied to different numbers of the chest electrodes 21 and different numbers of ECG signals, and can also be evaluated using QTc interval distribution tables with different numbers of points, such as the following Tables 5 to 8 and Figures 11 to 14 The above Tables 1 to 4 and the above Figures 6 to 9 of patients with Figure 10 The 24 chest electrodes 21 shown obtain 24 ECG signals. After calculating the QTc intervals of the ECG signals, a QTc interval distribution table of a total of 36 points (including the aforementioned 24 QTc intervals calculated from the ECG signals) is obtained through two-dimensional interpolation calculation and the corresponding image is displayed on the output unit 6.

[0090] Among them, in terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, 4 chest electrodes 21 in the chest electrodes 21 correspond to the right sternal edge 11, 5 chest electrodes 21 correspond to the left sternal edge 111, 4 chest electrodes 21 correspond to the midline 113 between the left sternal edge 111 and the left clavicle midline 112, 4 chest electrodes 21 correspond to the left clavicle midline 112, 4 chest electrodes 21 correspond to the left axillary front edge line 114, and 3 chest electrodes 21 correspond to the left axillary midline 13; in terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, two of the pre-chest electrodes 21 correspond to the first intercostal space corresponding to the height of the right sternal margin 11, three pre-chest electrodes 21 correspond to one second intercostal space corresponding to the height of the right sternal margin 11, five pre-chest electrodes 21 correspond to the third intercostal space corresponding to the height of the right sternal margin 11, six pre-chest electrodes 21 correspond to the fourth intercostal space corresponding to the height of the right sternal margin 11, five pre-chest electrodes 21 correspond to the fifth intercostal space corresponding to the height of the right sternal margin 11, and three pre-chest electrodes 21 correspond to the sixth intercostal space corresponding to the height of the right sternal margin 11.

[0091] After comparing the above Tables 1 to 4 and the above Figures 6 to 9 , and the following Tables 5 to 8 and Figures 11 to 14 It can be found that for the same patient, whether the 16 ECG signals (see Figure 3 ; 24-point QTc interval distribution table) or 24 ECG signals (see Figure 10 ; 36-point QTc interval distribution table) for calculation and analysis, consistent analysis results can be obtained when analyzing the location and range of myocardial ischemia. In some cases, analysis based on 24 ECG signals (36-point QTc interval distribution table) can more clearly identify areas with low QTc intervals (for example: Figure 14 Compared to Figure 9 It is obvious that the area with low QTc interval covers the three comparison areas 411 of the comparison information 41. In this embodiment, 24 ECG signals are analyzed (and a QTc interval distribution table of 36 points is obtained by two-dimensional interpolation calculation). QTc When the QTcD is greater than 9.4 msec or greater than 66 msec, it indicates significant myocardial ischemia and may require more aggressive treatment.

[0092] Table 5 shows an example of the QTc interval in a patient with left circumflex artery (LCX) stenosis of the left coronary artery:

[0093] 426 422 413 413 413 413 426 413 405 403 401 407 426 409 400 392 388 384 426 405 396 383 362 358 411 396 388 366 451 451 411 404 386 366 447 449

[0094] Table 6 shows an example of the QTc interval for a patient with right coronary artery (RCA) stenosis:

[0095] 398 398 411 411 411 411 413 417 425 409 408 410 417 428 356 390 405 408 428 348 390 394 409 409 394 360 398 394 409 413 394 377 392 402 398 405

[0096] Table 7 shows an example of the QTc interval in a patient with left anterior descending artery (LAD) stenosis:

[0097] 395 370 372 372 372 372 395 336 374 374 380 376 415 374 378 378 395 390 415 399 382 382 399 399 403 390 403 403 403 399 403 397 402 407 403 401

[0098] Table 8 shows an example of the QTc interval for a patient with three coronary artery stenosis (3VD):

[0099] 413 422 391 391 391 391 385 372 360 389 394 392 376 364 442 417 401 394 364 458 430 417 405 389 401 438 422 417 422 422 401 419 424 430 430 426

[0100] When evaluating the severity of overall myocardial ischemia, whether the first evaluation mode or the second evaluation mode is used, the main principle is to calculate the dispersion of the QTc interval. QTc The larger the value or the difference QTcD between the maximum and minimum values of the QTc interval, the more severe the overall myocardial ischemia of the human body 1 is.

[0101] For example, taking the analysis results of 16 ECG signals as an example, the SI in Table 1 QTc The value is 17.96, the difference between the maximum and minimum values of the QTc interval QTcD is 93, and the SI in Table 3 QTc The value is 7.58, and the difference between the maximum and minimum values of the QTc interval, QTcD, is 41. Therefore, whether the first evaluation mode or the second evaluation mode is used, it can be inferred that the severity of the overall myocardial ischemia of the patients in Table 1 is more serious than that of the patients in Table 3, and the SI in Table 1 is QTc Both the values and QTcD showed that the patients in Table 1 may need more aggressive treatment, thus having consistent assessment results.

[0102] In addition, taking the analysis results of 24 ECG signals as an example, Table 5 and Table 7 of the same patients as Table 1 and Table 3, the SI QTc The value is 13.35, the difference value QTcD between the maximum and minimum values of the QTc interval is 93, and the SI in Table 7 QTc The value is 9.11, and the difference between the maximum and minimum values of the QTc interval, QTcD, is 79. Therefore, it can be inferred that the severity of overall myocardial ischemia in the patients in Table 5 (i.e., the patients in Table 1) is more serious than that in the patients in Table 7 (i.e., the patients in Table 3). In other words, consistent analysis results can be achieved regardless of whether 16 or 24 ECG signals are used for analysis.

[0103] In addition, the arrangement of the chest electrodes 21 may not be limited to Figure 3 and Figure 10 The arrangement of Figure 15 For example, Figure 15 Another arrangement of 24 chest electrodes 21 is as follows: in terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, 3 chest electrodes 21 among the chest electrodes 21 correspond to the right sternal margin 11, 5 chest electrodes 21 correspond to the left sternal margin 111, 5 chest electrodes 21 correspond to the midline 113 between the left sternal margin 111 and the left clavicle midline 112, 4 chest electrodes 21 correspond to the left clavicle midline 112, 4 chest electrodes 21 correspond to the left axillary front edge line 114, and 3 chest electrodes 21 correspond to the left axillary midline 13; in terms of the transverse position of the chest electrodes 21 corresponding to the human body 1, 1 chest electrode 21 among the chest electrodes 21 corresponds to the right sternal margin 11, 5 chest electrodes 21 correspond to the midline 113 between the left sternal margin 111 and the left clavicle midline 112 The pre-chest electrodes 21 correspond to the second intercostal space and the height of the right sternal margin 11, four pre-chest electrodes 21 correspond to the third intercostal space and the height of the right sternal margin 11, five pre-chest electrodes 21 correspond to the fourth intercostal space and the height of the right sternal margin 11, five pre-chest electrodes 21 correspond to the fifth intercostal space and the height of the right sternal margin 11, four pre-chest electrodes 21 correspond to the sixth intercostal space and the height of the right sternal margin 11, and the five pre-chest electrodes 21 corresponding to the midline 113 between the left sternal margin 111 and the left clavicle midline 112 correspond to the heights of a third rib, the fourth rib, the fifth rib, the sixth rib and a seventh rib, respectively.

[0104] After actual measurement and analysis, based on Figure 15 The arrangement of the chest electrodes 21 disclosed herein can provide the same results as those obtained in analyzing the location and extent of myocardial ischemia and the severity of the patient's overall myocardial ischemia. Figure 3 and Figure 10 The arrangement of the chest electrodes 21 is consistent with the analysis results.

[0105] Also, see Figure 16, the number of the chest electrodes 21 can also be 36. In terms of the longitudinal position of the chest electrodes 21 corresponding to the human body 1, 7 chest electrodes 21 correspond to the right sternal margin 11, 7 chest electrodes 21 correspond to the left sternal margin 111, 7 chest electrodes 21 correspond to the midline 113 between the left sternal margin 111 and the left clavicle midline 112, 6 chest electrodes 21 correspond to the left clavicle midline 112, 5 chest electrodes 21 correspond to the left axillary front edge line 114, and 4 chest electrodes 21 correspond to the left axillary midline 13; in terms of the transverse position of the chest electrodes 21 corresponding to the human body 1, 2 chest electrodes 21 correspond to the first intercostal space corresponding to the height of the right sternal margin 11, 3 chest electrodes 21 correspond to the left midline 113 between the left sternal margin 111 and the left clavicle midline 112. The second intercostal space corresponds to the height of the right sternal margin 11, the four pre-chest electrodes 21 correspond to the third intercostal space corresponds to the height of the right sternal margin 11, the five pre-chest electrodes 21 correspond to the fourth intercostal space corresponds to the height of the right sternal margin 11, the five pre-chest electrodes 21 correspond to the fifth intercostal space corresponds to the height of the right sternal margin 11, the five pre-chest electrodes 21 correspond to the sixth intercostal space corresponds to the height of the right sternal margin 11, the five pre-chest electrodes 21 correspond to a seventh intercostal space corresponds to the height of the right sternal margin 11, and the seven pre-chest electrodes 21 corresponding to the midline 113 between the left sternal margin 111 and the left clavicle midline 112 correspond to the heights of a second rib, the third rib, the fourth rib, the fifth rib, the sixth rib, the seventh rib and the eighth rib respectively.

[0106] After actual measurement and analysis, based on Figure 16 The arrangement of the chest electrodes 21 disclosed above can also provide the same results as those in the previous examples when analyzing the location and extent of myocardial ischemia and the severity of the patient's overall myocardial ischemia. Figure 3 、 Figure 10 and Figure 15 The arrangement of the chest electrodes 21 is consistent with the analysis results.

[0107] According to the above description, the advantages of the myocardial ischemia detection device and myocardial ischemia detection method of the present invention include:

[0108] 1. The present invention uses the QT interval and the RR interval to calculate the characteristic value to detect the location of myocardial ischemia in the human body 1. Compared with existing analysis methods based on ST segment waveform changes, the QT interval and the RR interval are less affected by chest wall impedance, noise, and baseline offset, thereby avoiding evaluation errors.

[0109] Second, the present invention utilizes the electrocardiographic signal measurement location corresponding to at least one of the lowest characteristic values to detect the location of myocardial ischemia. Compared to existing methods that use the rising or falling ST segment waveform changes of the majority of leads in the same group as the basis for evaluation, the detection method of the present invention is relatively simple and can effectively improve its sensitivity.

[0110] 3. The numerical differences of the characteristic values and the corresponding distribution positions are imaged on the output unit 6 using different color levels, so that the user can easily and conveniently understand the high and low distribution of the characteristic values, thereby facilitating the assessment of the location and range of myocardial ischemia and effectively shortening the assessment time.

[0111] 4. Using a single indicator (i.e. SI QTc It is very simple to evaluate the severity of overall myocardial ischemia by using the value or the difference between the maximum and minimum values of the QTc interval (QTcD).

[0112] 5. By providing at least 16 pre-chest electrodes 21, the pre-chest electrodes 21 are arranged at special locations on the reference surface 100, and the processing unit 3 calculates the characteristic values based on the electrocardiographic signals, the characteristics of the electrocardiographic signals on the reference surface 100 can be fully provided. Therefore, even when applied to an unstressed human body 1, the location and range of chronic and acute myocardial ischemia in the human body 1 can be estimated. Moreover, since the number of pre-chest electrodes 21 is only at least 16, there is no need to increase the manufacturing cost too much and the device is very convenient to use.

[0113] 6. Since the chest electrodes 21 are arranged on the reference surface 100, the characteristic values calculated from the electrocardiographic signals measured by the 16 chest electrodes 21 can be expanded to 24 characteristic values through two-dimensional interpolation calculation. Compared with the traditional 12-lead electrocardiogram, the accuracy of judgment can be improved. Compared with the existing method of obtaining an electrocardiogram with more than 100 electrodes, the number of chest electrodes 21 can be reduced, thereby reducing costs and simplifying the positioning steps when the electrodes are attached to the human body 1.

[0114] 7. By setting the wearable unit 7, when the human body 1 wears the wearable unit 7, the chest electrodes 21 correspond to the predetermined positions of the reference surface 100, thereby simplifying the positioning and operation steps when setting the chest electrodes 21 on the human body 1, speeding up the operation process and ensuring the correct placement of the chest electrodes 21.

[0115] In addition, it should be specifically noted that in the present embodiment, each characteristic value is the QTc interval of the respective ECG signal. However, in other implementations, each characteristic value may also be the QT interval of the respective ECG signal (that is, it is not corrected with the RR interval, so there is no need to capture the RR interval of each ECG signal). The same effect can be achieved according to the above-mentioned detection steps.

[0116] In summary, the myocardial ischemia detection device and method of the present invention detect the location of myocardial ischemia in the human body 1 by calculating the characteristic value based on the QT interval and the RR interval. Compared with the existing analysis method based on ST segment waveform changes, the QT interval and the RR interval are less affected by chest wall impedance, noise, and baseline offset, thereby avoiding evaluation errors and truly achieving the purpose of the present invention.

[0117] The above descriptions are merely embodiments of the present invention and should not be used to limit the scope of the present invention. In other words, any simple equivalent changes and modifications made according to the claims and description of the present invention still fall within the scope of the present invention.

Claims

1. A myocardial ischemia detection device, suitable for use in a human body, characterized by: The myocardial ischemia detection device includes a measuring unit, a processing unit, and an output unit. The measuring unit includes four limb electrodes and a plurality of chest electrodes. The limb electrodes and the chest electrodes are adapted to obtain a plurality of electrocardiogram (ECG) signals from the human body. At least some of the chest electrodes have measurement locations corresponding to the left chest of the human body. The processing unit is signal-connected to the measuring unit and is capable of receiving the ECG signals. The processing unit is capable of extracting QT and RR intervals from the ECG signals and calculating, using the QT and RR intervals, a plurality of QTc interval characteristic values corresponding to a plurality of points on the left chest of the human body. The location of myocardial ischemia in the human body is then detected based on the ECG signal measurement location corresponding to at least one of the lowest of the characteristic values. and The output unit signal is connected to the measuring unit; The processing unit can image the numerical difference of the characteristic value and the corresponding distribution position on the output unit in different color levels. The processing unit can also calculate the discrete parameters using an evaluation parameter algorithm and evaluate the severity of the overall myocardial ischemia of the human body based on the discrete parameters. The evaluation parameter algorithm is: Among them, SI QTc is the discrete parameter, S is the total number of points, (QTc) k is the QTc interval of a specific point, n is the number of points closest to the specific point corresponding to the body position, (QTc) i The QTc interval of one of the points closest to the point corresponding to the human body position.

2. The myocardial ischemia detection device according to claim 1, wherein: The myocardial ischemia detection device further includes a database unit, which stores comparison information. The processing unit can compare the comparison information with the high and low distribution states of the characteristic values to detect the scope of the myocardial ischemia.

3. The myocardial ischemia detection device according to claim 2, wherein: The chest electrodes of the measuring unit are suitable for obtaining at least 16 of the electrocardiogram signals of the reference surface of the human body, and the reference surface is defined by the right sternal margin of the human body, the horizontal line of the first intercostal space corresponding to the height of the right sternal margin, the left axillary midline and the horizontal line of the eighth rib corresponding to the height of the right sternal margin.

4. The myocardial ischemia detection device according to claim 2, wherein: The processing unit can also calculate the difference value QTcD between the maximum value and the minimum value of the QTc interval at the point, and evaluate the severity of the overall myocardial ischemia of the human body based on the difference value between the maximum value and the minimum value of the QTc interval.

5. A method for detecting myocardial ischemia, characterized in that: The myocardial ischemia detection method comprises: a measuring step of obtaining a plurality of electrocardiogram (ECG) signals of a human body, wherein a measurement position of at least some of the ECG signals corresponds to the left chest of the human body; a feature extraction step of extracting the QT interval and the RR interval of each electrocardiogram signal by a processing unit, and calculating characteristic values of the QTc interval corresponding to a plurality of points on the left chest of the human body based on the QT interval and the RR interval; A first analysis step comprises comparing the point corresponding to at least one of the lowest eigenvalues with the position of the left chest of the human body, wherein the distribution of the eigenvalues is generated according to the position of the left chest of the human body, with different color levels representing the high and low eigenvalues, and detecting the extent of myocardial ischemia by comparing the image with the comparison information stored in the database unit; and The second analysis step is to calculate discrete parameters using an evaluation parameter algorithm, and evaluate the severity of the overall myocardial ischemia of the human body based on the discrete parameters. The evaluation parameter algorithm is: Among them, SI QTc is the discrete parameter, S is the total number of points, (QTc) k is the QTc interval of a specific point, n is the number of points closest to the point corresponding to the body position, (QTc) i is the QTc interval of one of the points closest to the point corresponding to the human body position.

6. The myocardial ischemia detection method according to claim 5, wherein: The measurement step is to obtain the electrocardiogram signal of the reference surface of the human body, and the reference surface is defined by the right sternal margin of the human body, the horizontal line of the first intercostal space corresponding to the height of the right sternal margin, the left axillary midline, and the horizontal line of the eighth rib corresponding to the height of the right sternal margin.

7. The myocardial ischemia detection method according to claim 5, wherein: The feature value calculated in the feature extraction step is a QTc interval corresponding to the point based on the electrocardiogram signal. The myocardial ischemia detection method further includes a second analysis step, which is to calculate the difference between the maximum and minimum values of the QTc interval at the point, and to assess the severity of the overall myocardial ischemia in the human body based on the difference value QTcD between the maximum and minimum values of the QTc interval.

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