阅读说明：本技术 一种基于心电同步的超声多普勒心功能包络峰识别方法 (Ultrasonic Doppler cardiac function envelope peak identification method based on electrocardio synchronization ) 是由 尹旻 张跃春 丁衍 于 2020-05-20 设计创作，主要内容包括：本发明公开了一种基于心电同步的超声多普勒心功能包络峰识别方法,超声多普勒信号与心电信号同步采集,通过比较两种数据各自的峰值,可以有效准确提取超声频谱峰,排除伪峰的干扰,提高包络识别和心排量参数计算的准确度。心电信号从宏观上记录心脏细胞的除极和复极过程,在一定程度上客观反映了心脏各部位的生理状况,因而在临床医学中有重要意义。并且多普勒超声和心电同样都是无创检测方法,正常的检测对人体基本无副作用,并且操作简单方便,亦可做监护使用。(The invention discloses an ultrasonic Doppler cardiac function enveloping peak identification method based on electrocardiographic synchronization, wherein an ultrasonic Doppler signal and an electrocardiographic signal are synchronously acquired, and the ultrasonic Doppler signal and the electrocardiographic signal can effectively and accurately extract an ultrasonic frequency spectrum peak by comparing respective peak values of two kinds of data, eliminate the interference of a false peak and improve the accuracy of enveloping identification and cardiac output parameter calculation. The electrocardiosignal macroscopically records the depolarization and repolarization processes of heart cells, objectively reflects the physiological conditions of all parts of the heart to a certain extent, and has important significance in clinical medicine. And Doppler ultrasound and electrocardio are non-invasive detection methods, normal detection has no side effect on human body basically, and the method is simple and convenient to operate and can also be used for monitoring.)

1. An ultrasonic Doppler cardiac function envelope peak identification method based on electrocardio synchronization is characterized by comprising the following steps:

s1: acquiring electrocardiosignals while acquiring ultrasonic signals, and calculating a Doppler frequency spectrum according to the ultrasonic signals to obtain a one-dimensional frequency spectrum array;

s2: carrying out envelope calculation on the frequency spectrum array to obtain an envelope point of the current frequency spectrum array, and carrying out smoothing processing on the envelope point to obtain a new smooth envelope point;

s3: processing the electrocardiosignals while processing the ultrasonic data, filtering the electrocardiosignals, and filtering the baseline drift to obtain the electrocardio data;

s4: determining the peak position of the R wave of the electrocardio data obtained in the step S3, and calculating the width of each QRS wave; storing each QRS wave band, analyzing whether the QRS wave band is arrhythmia or not, and marking the wave band of arrhythmia;

s5: selecting a data point from the smooth envelope point obtained in the step S2 according to the QRS wave width in the step S4 as a data set for peak identification, and comparing the size of the data point in the data set to find out the maximum point as an identified peak;

s6: calculating the peak position of the ultrasonic frequency spectrum peak identified in the step S5 and the peak position of the electrocardio waveform R wave obtained in the step S4 by adopting a peak top point to calculate time difference, and if the finally obtained time difference is smaller than a set time difference, considering the identified peak of the ultrasonic frequency spectrum as an effective peak, otherwise, considering the identified peak as a pseudo peak;

s7: determining the starting point and the ending point of the wave band of the ultrasonic frequency spectrum according to the peak position of the R wave and the width of the QRS wave obtained in the step S4 on the effective peak obtained in the step S6, thereby obtaining the data of the whole ultrasonic frequency spectrum;

s8: the ultrasonic spectrum band is divided into two parts according to whether the arrhythmia is detected in step S4, and parameter calculation is performed separately, that is, the cardiac output during the arrhythmia and the cardiac output during the normal period are calculated separately.

2. The method for recognizing the ultrasonic Doppler cardiac function envelope peak based on electrocardiographic synchronization according to claim 1, wherein the step S1 specifically includes:

s11: acquiring an ultrasonic signal and an electrocardiosignal at the same time;

s12: for ultrasonic signals, a section of new IQ signal ultrasonic data is obtained from an ultrasonic hardware module every time, and a Doppler frequency spectrum is calculated in a computer.

3. The ultrasound doppler cardiac function envelope peak identification method based on electrocardiographic synchronization according to claim 1 or 2, characterized in that: in step S2, for consistency of the envelope in the time domain, the envelope point of the current spectrum array needs to be combined with at least 5 previous envelope points in the time domain for smoothing processing, so as to obtain a new smooth envelope point.

4. The ultrasound doppler cardiac function envelope peak identification method according to any of claims 1 to 3, wherein the step S3 specifically includes:

s31: filtering the baseline drift of the electrocardiographic data by using median filtering to obtain an electrocardiographic waveform after the baseline drift is filtered;

s32: in order to remove the influence of P waves, T waves and noise, a band-pass filter is adopted to filter the electrocardiographic waveform after the baseline drift is filtered, and electrocardiographic data with QRS waves as main components are obtained.

5. The method for identifying the ultrasonic Doppler cardiac function envelope peak based on the electrocardiographic synchronization according to any one of claims 1 to 4, wherein the parameter calculation in the step S8 specifically comprises the following steps:

s81: calculating the blood flow rate: the formula is as follows:

where c is the speed of sound of ultrasound in the human body, f_dIs the frequency shift of the ultrasonic emission frequency and the receiving frequency, f is the emission frequency, and theta is the angle between the probe and the blood vessel;

s82: calculating the heart beat distance: the heart beat distance is obtained from the integrated area of the effective peak of the ultrasound spectrum obtained in step 1.5 (velocity time integral) and is given by:

where s is the heart beat distance, t₁At the peak start time, t₂V (t) is a function of the change of the speed along with the time, and is reflected on the image as an envelope;

s83: calculating the displacement of the heart, and the formula is as follows:

co＝s·hr·xsa

wherein hr is the heart rate, obtained from the time ratio of 60 seconds to the QRS wave of a single electrocardiographic waveform, xsa is the cross-sectional area of the arterial vessel of the human body, and co is the output cardiac output.

6. The ultrasound Doppler cardiac function envelope peak identification method based on electrocardiographic synchronization according to claim 4, characterized in that: in the step S32, a band-pass filter composed of a high-pass filter with a cut-off frequency of 10Hz and a low-pass filter with a cut-off frequency of 30Hz is used to filter the electrocardiographic waveform with the baseline drift removed, so as to obtain electrocardiographic data with QRS waves as a main component; wherein

The difference equation for the low pass filter used is:

y(nT)＝2y(n-1)T-y(n-2)T+xnT-2x(n-6)T+x(n-12)T

where T is the sampling period, n is an integer, and the corresponding system function is

The difference equation for the high pass filter used is:

y(nT)＝32x(n-16)T-[y(n-1)T+xnT-x(n-32)T]

where T is the sampling period, n is an integer, and the corresponding system function is

7. The ultrasound doppler cardiac function envelope peak identification method based on electrocardiographic synchronization according to any of claims 1 to 6, wherein: the set time difference in step S6 is 0.2 ms.

Technical Field

The invention relates to the technical field of medical signal and image processing, in particular to an ultrasonic Doppler cardiac function envelope peak identification method based on electrocardio synchronization.

Background

The ultrasonic Doppler cardiac output detection technology is a non-invasive method for monitoring cardiac output, and compared with the existing technology (Swan-Ganz catheter and Picco continuous cardiac output monitoring), the method has the characteristics of intuition, accuracy, non-invasiveness, sensitivity, good repeatability and the like. Existing devices using related technologies include cardiac function color ultrasonography, black and white ultrasonography, small portable ultrasonic testing devices, and the like.

The ultrasonic Doppler cardiac output detection technology displays the change of the cardiac output in real time by dynamic images and has an intuitive effect. And the ultrasonic Doppler is a non-invasive detection technology and has little side effect on human bodies. The ultrasonic Doppler detection technology is mature, and the accuracy is widely accepted internationally. The sensitivity is also quite high, and the change of the action of the medicine on the heart discharge can be observed.

The electrocardio is the comprehensive reflection of the electrical activity of countless cardiac muscle cells of the heart, and the generation of the electrocardio is closely inseparable with the processes of the depolarization and the repolarization of the cardiac muscle cells. The electrocardiosignal macroscopically records the depolarization and repolarization processes of heart cells, objectively reflects the physiological conditions of all parts of the heart to a certain extent, and has important significance in clinical medicine. The electrocardiosignal has important significance for synchronizing self multiple parameters and ultrasonic cardiac function signals.

At present, no method for analyzing and calculating by combining electrocardiosignals with an ultrasonic Doppler heart discharge detection technology exists.

Disclosure of Invention

The invention aims to provide an ultrasonic Doppler heart function envelope peak identification method based on electrocardio synchronization, which comprises the steps of automatically enveloping Doppler frequency spectrum, accurately and effectively identifying envelope peaks by combining electrocardio data, extracting two parts of ultrasonic frequency spectrum data whether the heart is arrhythmia or not and calculating heart function parameters of effective peaks.

In order to solve the technical problems, the technical scheme of the invention is as follows:

an ultrasonic Doppler cardiac function envelope peak identification method based on electrocardio synchronization comprises the following steps:

s1: acquiring electrocardiosignals while acquiring ultrasonic signals, and calculating a Doppler frequency spectrum according to the ultrasonic signals to obtain a one-dimensional frequency spectrum array;

s2: carrying out envelope calculation on the frequency spectrum array to obtain an envelope point of the current frequency spectrum array, and carrying out smoothing processing on the envelope point to obtain a new smooth envelope point;

s3: processing the electrocardiosignals while processing the ultrasonic data, filtering the electrocardiosignals, and filtering the baseline drift to obtain the electrocardio data;

s4: determining the peak position of the R wave of the electrocardio data obtained in the step S3, and calculating the width of each QRS wave; storing each QRS wave band, analyzing whether the QRS wave band is arrhythmia or not, and marking the wave band of arrhythmia;

s5: selecting a data point from the smooth envelope point obtained in the step S2 according to the QRS wave width in the step S4 as a data set for peak identification, and comparing the size of the data point in the data set to find out the maximum point as an identified peak;

s6: calculating the peak position of the ultrasonic frequency spectrum peak identified in the step S5 and the peak position of the electrocardio waveform R wave obtained in the step S4 by adopting a peak top point to calculate time difference, and if the finally obtained time difference is smaller than a set time difference, considering the identified peak of the ultrasonic frequency spectrum as an effective peak, otherwise, considering the identified peak as a pseudo peak;

s7: determining the starting point and the ending point of the wave band of the ultrasonic frequency spectrum according to the peak position of the R wave and the width of the QRS wave obtained in the step S4 on the effective peak obtained in the step S6, thereby obtaining the data of the whole ultrasonic frequency spectrum;

s8: the ultrasonic spectrum band is divided into two parts according to whether the arrhythmia is detected in step S4, and parameter calculation is performed separately, that is, the cardiac output during the arrhythmia and the cardiac output during the normal period are calculated separately.

Preferably, the step S1 specifically includes:

s11: acquiring an ultrasonic signal and an electrocardiosignal at the same time;

s12: for ultrasonic signals, a section of new IQ signal ultrasonic data is obtained from an ultrasonic hardware module every time, and a Doppler frequency spectrum is calculated in a computer.

Preferably, in step S2, for consistency of the envelope in the time domain, the envelope point of the current spectrum array needs to be combined with at least 5 previous envelope points in the time domain for smoothing processing, so as to obtain a new smoothed envelope point.

Preferably, the step S3 specifically includes:

s31: filtering the baseline drift of the electrocardiographic data by using median filtering to obtain an electrocardiographic waveform after the baseline drift is filtered;

s32: in order to remove the influence of P waves, T waves and noise, a band-pass filter is adopted to filter the electrocardiographic waveform after the baseline drift is filtered, and electrocardiographic data with QRS waves as main components are obtained.

Preferably, the parameter calculation in step S8 specifically includes the following steps:

s81: calculating the blood flow rate: the formula is as follows:

where c is the speed of sound of ultrasound in the human body, f_dIs the frequency shift of the ultrasonic emission frequency and the receiving frequency, f is the emission frequency, and theta is the angle between the probe and the blood vessel;

s82: calculating the heart beat distance: the heart beat distance is obtained from the integrated area of the effective peak of the ultrasound spectrum obtained in step 1.5 (velocity time integral) and is given by:

where s is the heart beat distance, t₁At the peak start time, t₂V (t) is a function of the change of the speed along with the time, and is reflected on the image as an envelope;

s83: calculating the displacement of the heart, and the formula is as follows:

co＝s·hr·xSa

wherein hr is the heart rate, obtained from the time ratio of 60 seconds to the QRS wave of a single electrocardiographic waveform, xsa is the cross-sectional area of the arterial vessel of the human body, and co is the output cardiac output.

Preferably, in step S32, a band-pass filter composed of a high-pass filter with a cutoff frequency of 10Hz and a low-pass filter with a cutoff frequency of 30Hz is used to filter the electrocardiographic waveform with the baseline drift removed, so as to obtain electrocardiographic data with QRS waves as a main component; wherein

The difference equation for the low pass filter used is:

y(nT)＝2y(n-1)T-y(n-2)T+xnT-2x(n-6)T+x(n-12)T

where T is the sampling period, n is an integer, and the corresponding system function is

The difference equation for the high pass filter used is:

y(nT)＝32x(n-16)T-[y(n-1)T+xnT-x(n-32)T]

where T is the sampling period, n is an integer, and the corresponding system function is

Preferably, the set time difference in step S6 is 0.2 ms.

By adopting the technical scheme, the invention at least comprises the following beneficial effects:

according to the ultrasonic Doppler cardiac function envelope peak identification method based on electrocardio synchronization, the ultrasonic Doppler signals and the electrocardio signals are synchronously collected, the ultrasonic frequency spectrum peak can be effectively and accurately extracted by comparing the respective peak values of the two data, the interference of a false peak is eliminated, and the accuracy of envelope identification and the accuracy of cardiac output parameter calculation are improved. The electrocardiosignal macroscopically records the depolarization and repolarization processes of heart cells, objectively reflects the physiological conditions of all parts of the heart to a certain extent, and has important significance in clinical medicine. And Doppler ultrasound and electrocardio are non-invasive detection methods, normal detection has no side effect on human body basically, and the method is simple and convenient to operate and can also be used for monitoring.

Drawings

FIG. 1 is a flow chart of the ultrasonic Doppler cardiac function envelope peak identification method based on electrocardiographic synchronization according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the method for identifying an ultrasound doppler cardiac function envelope peak based on electrocardiographic synchronization according to the present invention comprises the following steps:

s1: acquiring electrocardiosignals while acquiring ultrasonic signals, and calculating a Doppler frequency spectrum according to the ultrasonic signals to obtain a one-dimensional frequency spectrum array;

s2: carrying out envelope calculation on the frequency spectrum array to obtain an envelope point of the current frequency spectrum array, and carrying out smoothing processing on the envelope point to obtain a new smooth envelope point;

s3: processing the electrocardiosignals while processing the ultrasonic data, filtering the electrocardiosignals, and filtering the baseline drift to obtain the electrocardio data;

s4: determining the peak position of the R wave of the electrocardio data obtained in the step S3, and calculating the width of each QRS wave; storing each QRS wave band, analyzing whether the QRS wave band is arrhythmia or not, and marking the wave band of arrhythmia;

s5: selecting a data point from the smooth envelope point obtained in the step S2 according to the QRS wave width in the step S4 as a data set for peak identification, and comparing the size of the data point in the data set to find out the maximum point as an identified peak;

s6: calculating the peak position of the ultrasonic frequency spectrum peak identified in the step S5 and the peak position of the electrocardio waveform R wave obtained in the step S4 by adopting a peak top point to calculate time difference, and if the finally obtained time difference is smaller than a set time difference, considering the identified peak of the ultrasonic frequency spectrum as an effective peak, otherwise, considering the identified peak as a pseudo peak;

s7: determining the starting point and the ending point of the wave band of the ultrasonic frequency spectrum according to the peak position of the R wave and the width of the QRS wave obtained in the step S4 on the effective peak obtained in the step S6, thereby obtaining the data of the whole ultrasonic frequency spectrum;

s8: the ultrasonic spectrum band is divided into two parts according to whether the arrhythmia is detected in step S4, and parameter calculation is performed separately, that is, the cardiac output during the arrhythmia and the cardiac output during the normal period are calculated separately.

Preferably, the step S1 specifically includes:

s11: acquiring an ultrasonic signal and an electrocardiosignal at the same time;

s12: for ultrasonic signals, a section of new IQ signal ultrasonic data is obtained from an ultrasonic hardware module every time, and a Doppler frequency spectrum is calculated in a computer.

Preferably, in step S2, for consistency of the envelope in the time domain, the envelope point of the current spectrum array needs to be combined with at least 5 previous envelope points in the time domain for smoothing processing, so as to obtain a new smoothed envelope point.

Preferably, the step S3 specifically includes:

s31: filtering the baseline drift of the electrocardiographic data by using median filtering to obtain an electrocardiographic waveform after the baseline drift is filtered;

s32: in order to remove the influence of P waves, T waves and noise, a band-pass filter is adopted to filter the electrocardiographic waveform after the baseline drift is filtered, and electrocardiographic data with QRS waves as main components are obtained.

Preferably, the parameter calculation in step S8 specifically includes the following steps:

s81: calculating the blood flow rate: the formula is as follows:

wherein c is ultrasound in humansSpeed of sound in the body, f_dIs the frequency shift of the ultrasonic emission frequency and the receiving frequency, f is the emission frequency, and theta is the angle between the probe and the blood vessel;

s82: calculating the heart beat distance: the heart beat distance is obtained from the integrated area of the effective peak of the ultrasound spectrum obtained in step 1.5 (velocity time integral) and is given by:

where s is the heart beat distance, t₁At the peak start time, t₂V (t) is a function of the change of the speed along with the time, and is reflected on the image as an envelope;

s83: calculating the displacement of the heart, and the formula is as follows:

co＝s·hr·xsa

wherein hr is the heart rate, obtained from the time ratio of 60 seconds to the QRS wave of a single electrocardiographic waveform, xsa is the cross-sectional area of the arterial vessel of the human body, and co is the output cardiac output.

Preferably, in step S32, a band-pass filter composed of a high-pass filter with a cutoff frequency of 10Hz and a low-pass filter with a cutoff frequency of 30Hz is used to filter the electrocardiographic waveform with the baseline drift removed, so as to obtain electrocardiographic data with QRS waves as a main component; wherein

The difference equation for the low pass filter used is:

y(nT)＝2y(n-1)T-y(n-2)T+xnT-2x(n-6)T+x(n-12)T

where T is the sampling period, n is an integer, and the corresponding system function is

The difference equation for the high pass filter used is:

y(nT)＝32x(n-16)T-[y(n-1)T+xnT-x(n-32)T]

where T is the sampling period, n is an integer, and the corresponding system function is

Preferably, the set time difference in step S6 is 0.2 ms.

The invention provides a method for recognizing an envelope peak of an ultrasonic Doppler cardiac function in combination with electrocardio, which comprises the steps of synchronously acquiring a cardiac output signal and an electrocardio signal at a relevant part of a human body by simultaneously adopting an ultrasonic Doppler probe and an electrocardio electrode slice, and inputting the two signals into a computer for processing. The computer combines the cardiac output signal and the electrocardiosignal to automatically analyze and envelope the effective peak, and then calculates the cardiac output parameter and the electrocardio parameter. The invention can use the electrocardio parameters to match the ultrasonic Doppler spectrum envelope so as to effectively extract the real peak, and obtains the relevant parameters reflecting the cardiac function by calculating the effective envelope peak, thereby reflecting the basic physiological condition and the change of the cardiac function of the human body. The invention can also use the electrocardio-parameters to eliminate the ultrasonic frequency spectrum waveform when the heart rhythm is abnormal. The present invention is specifically illustrated by the following examples.

The invention relates to a method for identifying an envelope peak of an ultrasonic Doppler cardiac function in combination with electrocardio, which mainly comprises two parts of ultrasonic Doppler frequency spectrum analysis and parameter calculation in combination with the electrocardio. The ultrasonic Doppler spectrum analysis combined with electrocardio comprises steps S1-S7, and the parameter calculation comprises step S8.

Step S1, acquiring electrocardiosignals while acquiring signals by an ultrasonic probe, acquiring a section of new IQ signal ultrasonic data from an ultrasonic hardware module for real-time signals each time, and calculating a Doppler frequency spectrum in a computer, wherein the process comprises the steps of firstly carrying out Fourier transform on IQ signals and then calculating amplitude values to obtain a one-dimensional frequency spectrum array;

step S2, performing envelope calculation on the spectrum array to obtain an envelope point of the current spectrum array, and for consistency of the envelope in the time domain, performing smoothing processing on the envelope point of the current spectrum array in combination with at least 5 previous envelope points in the time domain to obtain a new smooth envelope point.

Step S3, processing the ultrasonic data and the electrocardio data, filtering the baseline drift of the electrocardio data by using median filtering, wherein the median filtering is to take a section of data N (taking odd number) before a data point, sort the section of data, then take the middle one-digit value as the data of the point, process the whole section of electrocardio signal as above, extract the baseline drift part in the signal, and finally subtract the baseline drift component from the original signal to obtain the electrocardio data after the baseline drift is filtered; in order to remove the influence of P waves, T waves and noise, a band-pass filter consisting of a high-pass filter with the cut-off frequency of 10Hz and a low-pass filter with the cut-off frequency of 30Hz is adopted to filter the electrocardiographic waveform after the baseline drift is filtered, and the electrocardiographic data with the QRS waves as the main component is obtained.

The difference equation for the low pass filter used therein is:

y(nT)＝2y(n-1)T-y(n-2)T+xnT-2x(n-6)T+x(n-12)T

where T is the sampling period, n is an integer, and the corresponding system function is

The difference equation for the high pass filter used is:

y(nT)＝32x(n-16)T-[y(n-1)T+xnT-x(n-32)T]

where T is the sampling period, n is an integer, and the corresponding system function is

Step S4, determining the peak position of the R wave for the electrocardiographic data obtained in step S3, and determining the position of the R wave in order to accurately and effectively detect the R wave in the electrocardiographic data by combining some decision strategies, first, threshold detection is performed, in order to adapt to the change of the electrocardiographic waveform characteristics with time, the position of the R wave is determined by combining a fixed threshold and a variable threshold, the initial threshold formula is Ts1 ═ m × max (a2), where m is 0.6, the position of the first R wave peak is found maxR1 according to the initial threshold, and then, the detection threshold is adaptively modified by combining the average value of all the detected R wave peaks, and the formula is Ts (n) ═ 0.2Ts1+0.5meanR_n-1In addition, the electrocardio refractory period is still set to be 200ms in the algorithm, and each time an R wave is detected, a sampling point corresponding to the 200ms later time is omitted, and the R wave is detected from the later sampling point again. The specific detection process is as follows:

firstly, performing multi-scale decomposition on electrocardiogram data by using sym4 wavelet to obtain a reconstructed second-layer approximate detail signal a2, then taking data of the front 1/5 part of a2, calculating a maximum value to obtain an initial threshold value Ts1, starting to search for a point greater than the initial threshold value, and finding out a maximum point greater than the threshold value in a specified range by adopting a time domain windowing method, wherein the maximum point is a first R wave peak value; and modifying the threshold according to an adaptive threshold formula, taking the new threshold as a reference, searching a new R wave peak value after a refractory period interval from the last R wave peak value, and storing the found peak value position into an array.

The current methods for detecting the QRS complex width are many, and most commonly, the method is still a difference method. The QRS complex width detection algorithm is mostly based on a difference method, and has the greatest advantages that the QRS complex with high-frequency characteristics can be enhanced, and the P wave and the T wave with low-frequency characteristics are weakened at the same time, so that the QRS complex is converted into a pulse signal equivalent to the QRS width, and other parts of an electrocardiosignal are converted into horizontal lines, so that the period of the pulse signal is conveniently determined, and the width of the pulse signal is the width of the QRS complex; and storing each QRS wave band, and then carrying out arrhythmia analysis on the QRS wave bands by using a support vector machine classification algorithm to mark the arrhythmia wave bands.

And S5, selecting data points as a data set for peak identification according to the smooth envelope points obtained in the step S2 and the QRS wave width in the step S4, and comparing the sizes of the data points in the data set to find out the maximum value point as the identified peak.

Step S6, calculating the time difference between the peak of the ultrasonic frequency spectrum identified in the step S5 and the peak position of the electrocardio waveform R wave obtained in the step S4 by adopting the peak top point, if the finally obtained time difference is less than the range of 0.2ms, the identified peak of the ultrasonic frequency spectrum is considered as an effective peak, otherwise, the identified peak is considered as a false peak;

and step S7, determining the starting point and the ending point of the wave band of the ultrasonic spectrum according to the peak position of the R wave and the width of the QRS wave obtained in the step S4 on the effective peak obtained in the step S6, thereby obtaining the data of the whole ultrasonic spectrum.

The ultrasonic spectral band is then divided into two parts, with reference to whether it is an arrhythmia at step S4.

Preferably, the parameter calculation in step S8 specifically includes the following steps:

s81: calculating the blood flow rate: the formula is as follows:

where c is the speed of sound of ultrasound in the human body, f_dIs the frequency shift of the ultrasonic emission frequency and the receiving frequency, f is the emission frequency, and theta is the angle between the probe and the blood vessel;

s82: calculating the heart beat distance: the heart beat distance is obtained from the integrated area of the effective peak of the ultrasound spectrum obtained in step 1.5 (velocity time integral) and is given by:

where s is the heart beat distance, t₁At the peak start time, t₂V (t) is a function of the change of the speed along with the time, and is reflected on the image as an envelope;

s83: calculating the displacement of the heart, and the formula is as follows:

co＝s·hr·xsa

wherein hr is the heart rate, obtained from the time ratio of 60 seconds to the QRS wave of a single electrocardiographic waveform, xsa is the cross-sectional area of the arterial vessel of the human body, and co is the output cardiac output.

Compared with the prior art, the invention has the following advantages:

1. the ultrasonic Doppler signal and the electrocardiosignal are synchronously acquired, and the peak values of the two data are compared, so that the ultrasonic frequency spectrum peak can be effectively and accurately extracted, the interference of a false peak is eliminated, and the accuracy of envelope identification and the accuracy of heart displacement parameter calculation are improved;

2. for identifying the ultrasonic spectrum envelope peak by combining the heart sound, the electrocardio can identify an arrhythmia part relative to the heart sound, so that the obtained ultrasonic frequency band data of whether the arrhythmia is obtained or not are respectively subjected to parameter calculation, namely the cardiac output during the arrhythmia and the cardiac output during the normal period;

3. the electrocardiosignal macroscopically records the depolarization and repolarization processes of heart cells, objectively reflects the physiological conditions of all parts of the heart to a certain extent, and has important significance in clinical medicine. (ii) a

4. Doppler ultrasound and electrocardio are also non-invasive detection methods, normal detection has no side effect on human body basically, and the method is simple and convenient to operate and can also be used for monitoring.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.