Research On Variability Of Cardiac Reserve Index Based On Heart Sound

The thesis focuses on the variability analysis of heart reserve indexs in order to offset the weakness of these indexes in practical application. The research proposes dynamic indexes to evaluate the state of the heart which contain more useful information. The contents of thesis are as follows:â‘ The design of noninvasive cardiac reserve monitoring system softwareThis software contains two modules: heart sound signal is acquired from sound card and saved as wav files in the record-display module. In the data-analysis module, the wav files are parsed firstly, then indexes for evaluating cardiac reserve are gained, finally, the data acquired in this module is saved into Excel file for further analysis.â‘¡Comparison of researches on the methods for heart sound analysisThis thesis summarizes recent methods for heart sound analysis firstly, and proposes the characters and differences in the analysis. These methods are divided into three parts according articles searched in database: spectral analysis, STFT and wavelet transform. These methods are applied into pilot study of heart sound.â‘¢Research on heart sound segmentation algorithmsCombining the previous researches with real requirement, the thesis proposes Hilbert-Huang transform and complexity. In the Hilbert-Huang transform , S1 and S2 are located,indexes such as heart rate, S1/S1 and D/S are obtained according duration relationship of heart sound. In addition, the two thresholds used in segmentation are definite. In the complexity algorithm, it gives the empirical values of the two key parameters in the analysis process. S1 and S2 are located as goal areas, there are high division between goal areas and non-goal areas.â‘£Statistic analysis among normal personsIn the thesis, data is divided into two teams according different research purposes. Every sample has 5 seconds heart sound signal in one team, there are 631 samples in this team (374 males, 257 females) whose ages ranged form 18 to 22 years. Every sample has 24 seconds heart sound signal in the other team, there are 72 samples in this team whose ages ranged from 19 to 23 years. It answers the questions: whether there are variances between male and female's D/S, whether breath has effect on S1/S2. In the final, it proposes the reference values for variances of cardiac reserve indexes in healthy college students.