The Heart Sound Acquisition And Cardiac Reserve Analysis System Based On LabVIEW

Cardiac Reserve(CR),which refers to the ability to increase cardiac function,is a very important indicator of the balance of the heart function.Through the examination of cardiac reserve,patients can understand the current state of their hearts.At present,the detection methods of cardiac reserve function include electrocardiogram,echocardiography,and heart sounds detection.Electrocardiogram can detect cardiac chronotropic and cardiac inotropic;echocardiography can detect myocardial status,but it is expensive;the amplitude of the first heart sounds is related to the change of myocardial contractility.Therefore,heart sounds can make up for the deficiency of electrocardiogram and echocardiography with important clinical diagnostic information.Therefore,to supplement the deficiency of electrocardiogram and echocardiography.Small,portable,cheap,convenient and real-time analysis of cardiac reserve capacity is very necessary.At present,in the acquisition of cardiac sounds,Digital stethoscope and BIOPAC heart sound acquisition system are used in biomedical signal laboratory.Although Digital stethoscope is small in size,However,it is not possible to directly analyze and process the collected heart sound data after the acquisition of heart sound.BIOPAC heart sound acquisition system does not have real-time auscultation function,is not convenient to the doctor for clinical auscultation and analysis,and BIOPAC heart sounds of the high price of acquisition system,large volume,for collectors and inconvenient to carry.In terms of cardiac reserve analysis,due to the existence of physiological,pathological and acquisition environment factors,the clinical cardiac tone signal is extremely complex.Therefore,the algorithm of cardiac signal is further analyzed,and the desiccation and feature extraction algorithm of cardiac signal are used.Using wavelet threshold shrinkage method for noise reduction,noise reduction after the analysis on the characteristics of heart sound wave extraction,and determine the position of the first heart sound and second heart sounds and extract the evaluating cardiac reserve three characteristic indexes(HR,D/S,S1 / S2).In view of the above problems,This paper designs and develops a set of heart sound acquisition and heart reserve analysis system.STC15W408 AS data acquisition card is low in price and stable in performance,and can be directly connected to the upper computer for realtime heart reserve analysis after data collection.Finally,Lab VIEW is used to call the heart sound algorithm,so as to realize the evaluation system of convenient,intelligent and noninvasive cardiac reserve function.Meanwhile,in the current national natural science foundation work carried out by biomedical signal room,one of the needs is to establish a complete,realtime and portable system for heart sounds acquisition and reserve analysis.Therefore,this study designs a set of Lab VIEW-based heart sounds acquisition and cardiac reserve analysis system.The system includes two parts,namely,heart sounds data acquisition card and Lab VIEW software.In this paper,the hardware design and Lab VIEW software programming of data acquisition card are introduced in detail.The functions of real-time acquisition,serial port transmission,real-time waveform display and heart reserve ability are realized.By analyzing the results of cardiac reserve capacity,the author offers preliminary decision results of positive.abnormal heart sounds,heart rate,the ratio of first to second heart sounds amplitude S1/S2 and the ratio of systolic to diastolic time D/S,providing certain reference for the comprehensive evaluation of cardiac reserve capacity.In order to achieve the above objectives,this paper studies from the following aspects:(2)The basic knowledge of the heart sounds signal.From the medical point of view,understand the production of heart sounds,basic characteristics of heart sounds and heart murmur.it proposed the necessity of this study.(2)Heart sound acquisition,preprocessing and extraction of characteristic parameters.The traditional methods of collecting heart sound signals and the characteristics of collecting heart sound data cards are described in detail.The site of the auscultation is introduced.The research of analysis algorithm for heart sound.The final definition of heart sound characteristic parameters,the parameters are used to recognize normal and abnormal heart sounds,so as to verify the effectiveness of the algorithm.(3)The hardware design of the heart sounds data acquisition card.The design of heart sounds data acquisition card based on STC15W408 AS is presented,including heart sounds sensor,amplifying circuit module,low-pass filter module,audio power amplifier module,A/D conversion module,serial port communication module and power module and so on.(4)The design of Lab VIEW cardiac reserve analysis software.First of all,it gives presentation about the work flow and basic function of this software;secondly,it introduces the user login module,information input module of the person detected,serial port communication module,display module,data storage module,heart sounds data playback module,heart sounds analysis module,report printing module and generating installation files.(5)Test of cardiac reserve analysis system and validation of effectiveness.Combining the heart sounds data acquisition card and Lab VIEW cardiac reserve analysis software,the test results of data acquisition card and the test results of Lab VIEW cardiac reserve analysis software are given.Finally,the heart sounds data of 56 groups of college students are collected,and the statistics and analysis are carried out by grouping.At the same time,the existing data of biomedical signal laboratory are compared and analyzed.Cardiac reserve analysis and statistics were performed in 8 children,7 athletes and 5 patients with heart diseaseThe Heart Sound Acquisition and Cardiac Reserve Analysis System Based on Lab VIEW,Completed the real-time acquisition of heart sounds by data acquisition card and real-time cardiac reserve analysis using PC.Through the test of the system and analysis and comparison of multiple groups of data,The system can effectively collect heart sound data and extract cardiac reserve parameters accurately,and carry out effective cardiac reserve analysis.