Heart Failure ; diagnosis ; therapy ; Humans ; Phonocardiography ; methods

In this paper, an improved empirical mode decomposition (EMD) algorithm for phonocardiogram (PCG) signal de-noising is proposed. Based on PCG signal processing theory, the S1/S2 components can be extracted by combining the improved EMD-Wavelet algorithm and Shannon energy envelope algorithm. Firstly, by applying EMD-Wavelet algorithm for pre-processing, the PCG signal was well filtered. Then, the filtered PCG signal was saved and applied in the following processing steps. Secondly, time domain features, frequency domain features and energy envelope of the each intrinsic mode function's (IMF) were computed. Based on the time frequency domain features of PCG's IMF components which were extracted from the EMD algorithm and energy envelope of the PCG, the S1/S2 components were pinpointed accurately. Meanwhile, a detecting fixed method, which was based on the time domain processing, was proposed to amend the detection results. Finally, to test the performance of the algorithm proposed in this paper, a series of experiments was contrived. The experiments with thirty samples were tested for validating the effectiveness of the new method. Results of test experiments revealed that the accuracy for recognizing S1/S2 components was as high as 99.75%. Comparing the results of the method proposed in this paper with those of traditional algorithm, the detection accuracy was increased by 5.56%. The detection results showed that the algorithm described in this paper was effective and accurate. The work described in this paper will be utilized in the further studying on identity recognition.
Algorithms ; Humans ; Phonocardiography ; Signal Processing, Computer-Assisted

According to the valvular theory, the vibrations affected by the mitral and tricuspid valves closure in early systole produce the first heart sound (S1). S1 usually includes many frequency components. In this paper, a method using the multi-resolution analysis of wavelet transformation is recommended for detecting the frequency range of S1. First, S1 was decomposed into different levels on frequency. Then the normalized Shannon energy of the different levels was calculated. The level containing the maximum energy is the major components' level of S1. The frequency range of this level is the major frequency range of S1. The frequency range of S1 was successfully detected by the method.
Algorithms ; Heart Sounds ; Humans ; Phonocardiography ; methods ; Signal Processing, Computer-Assisted

BACKGROUND: The rate of rise of left ventricular(LV) systolic pressure, dp/kt, and the peak ejection rate(PER) of LV may be more accurate indices for assessing LV systolic function than ejection fraction(EF). Both can be easily obtained by noninvasive methods, M-mode echo/phonocardiography and automated border detection(ABD) echocardiography, respectively. Mean dp/dt by M-mode echo/phonocardiography and PER by ABD echocardiography were compared with mean dp/dt by Doppler echocardiography. METHODS: Twenty-one adult patients who had normal sinus rhythm, mitral regurgitant signals by continuous wave Doppler echocardiography and an apical 4 chamber view of LV in which at least 75% of the endocardium was clearly visualized were selected for our study. The off-line estimation of LV end-diastolic volume (1) were performed by the method of disc, after manually tracing the endocardial border on the apical 4 chamber view and EF was calculated. M-mode echocardiography of the aortive valve and phonocardiography were simultaneously recorded on the strip chart to measure the isovolumic contraction time(dtM). A blood pressure (2) and LV end-diasolic pressure(LVEDP) was assigned 20mmHg in patients with Q wave myocardial infarction or EF< or =40% and 10mmHg in others. The mean dp/dtM during isovolumic contraction time was calculated as (aortic diastolic pressure-LVEDP)/dtM and was compared with the Doppler-derived mean rate of LV pressure rise(dp/dtDoppler) over the time period between velocities of 1 and 3m/sec on the ascending slope of the Doppler velocity spectrum. ABD system was used to measure the changes in LV volume and PER on the apical four chamber view. PER was compared with mean dp/dtDoppler. RESULTS: Mean dp/dtM positively correlated with mean dp/dtDoppler(r=0.73, p<0.001), but the limits of agreement between two methods were somewhat wide(-659-937mmHg/sec). PER also positively correlated with dp/dtDoppler and EF(r=0.73, p<0.001 ; r=0.80, p<0.001). CONCLUSIONS: Mean dp/dtM by M-mode echo/phomocardiography and PER by ABD echocardiography may be useful indices for assessing LV systolic function.
Adult ; Blood Pressure ; Echocardiography* ; Echocardiography, Doppler ; Endocardium ; Humans ; Myocardial Infarction ; Phonocardiography

Phonocardiography is the graphic registration of various bands of the vibratory spectrum. We used the phonocardiogram as a monitoring apparatus. A 62-year-old man was scheduled for mitral valve replacement. After induction of general anesthesia and tracheal intubation, we inserted an esophageal stethoscope attached with a wireless microphone, amplifier, galvanometer and transcription system. The resulting phonocardiogram revealed a pan-systolic murmur. After successful replacement of the mitral valve, the phonocardiogram showed no sign of heart murmur. So we are convinced that the application of the phonocardiogram can be a useful monitoring device for valvular surgery.
Anesthesia, General ; Heart Murmurs ; Humans ; Intubation ; Middle Aged ; Mitral Valve* ; Phonocardiography ; Stethoscopes

Recently, the proportion of cardiovascular disease as a cause of death in diabetics is in ever increasing tendency. Present study is designed to evaluate the change of myocardial performance by the effect of microangiopathy of diabetics. The measurements of systolic time intervals were obtained from simultaneous high speed recordings(100mm/sec) of electrocardiography, phonocardiography, and carotid pulse tracing in diabetics(male 26, female 31). 1. As the diabetic retinopathy got severe, shortening of LVET and prologation of PEP were noted, but QS2 showed no significant change. 2. PEP/LVET ratio fo diabetics without diabetic retinopathy was significantly higher than that of normal control(p<0.01). 3. PEP/LVET ratio of diabetics with diastolic blood pressure under 95mmHg was significantly higher than that of normal control group(p<0.01), and PEP/LVET ratio of diabetics with diastolic blood pressure over 96mmHg was significantly higher than that of normal control and that of diabetics with diastolic blood pressure under 95mmHg(p<0.01). 4. PEP/LVET ratio of diabetics with proliperative retinopathy was significantly higher than that of normal control and that of diabetics with mild diabetic retinopathy(p<0.01), but this result was not conclusive because of the small case number.
Blood Pressure ; Cardiovascular Diseases ; Cause of Death ; Diabetic Retinopathy ; Electrocardiography ; Female ; Humans ; Phonocardiography ; Systole*

As an important human body sound signal, heart sound is of great value in the researches on diagnostics of heart diseases. This study sought to explore the methods of transmitting heart sound through the telephone correspondence system for simultaneous telemetering cardiac contractility and heart rate. Heart sounds were transmitted from a phone to another phone with 4 modes, the wirelessly transmitted distance between the two phones being 5 m, 10 km, and 1000 km, respectively. The results of experiments show that telemetering cardiac contractility and heart rate can be realized by the telephone correspondence system. Such methods have the advantages of being noninvasive, inexpensive, rapid and convenient; moreover, they can be used repeatedly and be available for in-home use.
Heart Sounds ; physiology ; Humans ; Phonocardiography ; instrumentation ; methods ; Signal Processing, Computer-Assisted ; instrumentation ; Telemedicine ; methods ; Telemetry ; methods

Heart sound signals acquisition is the primary basis for achieving non-invasive diagnosis of coronary heart disease. In this paper, a digital signal processor (DSP)-based on miniaturized circuit of heart sound signals acquisition and analysis platform was designed to achieve the functions of filtering, collecting, processing, displaying and the communicating with PC. With the self-developed experimental platform, we collected 228 cases of heart sounds of clinical data, and processed the signals using de-noising method with wavelet transform. These experimental results indicated that the db6 wavelet has the most obvious de-noising effect among the four most commonly used wavelets, i.e., haar, db6, sym8, and coif5. One wavelet at different levels possessed different de-noising effects, with level-5 db6 decomposition obtaining the most desirable result.
Algorithms ; Auscultation ; Heart Sounds ; Humans ; Phonocardiography ; methods ; Signal Processing, Computer-Assisted ; Wavelet Analysis

Phonocardiogram exercise testing(PCGET) is a recently developed method for evaluating cardiac contractility and the cardiac reserve of patients with heart disease and of healthy subjects. In order to test the reliability of PCGET method in physical sport, the present author conducted a clinical study. The ratio of the amplitude of the first heart sound after PCGET to that recorded at rest was defined as an indicator, i.e. cardiac contractility reserve index (CCRI). PCGET was performed on 30 athletes and 30 non-athletes. The results showed that the average of CCRI was 10.139 +/- 2.631 in 30 athletes and 6.612 +/- 3.104 in 30 non-athletes. There was a significant difference between CCRI of the two groups (P < 0.01). Thus, PCGET might be a noninvasive, convenient and inexpensive technique to evaluate the cardiac reserve quantitatively for athletes.
Adolescent ; Adult ; Exercise Test ; methods ; Feasibility Studies ; Humans ; Myocardial Contraction ; physiology ; Phonocardiography ; methods ; Sports ; physiology

OBJECTIVEExtraction of cepstral coefficients combined with Gaussian Mixture Model (GMM) is used to propose a biometric method based on heart sound signal.

METHODSFirstly, the original heart sounds signal was preprocessed by wavelet denoising. Then, Linear Prediction Cepstral Coefficients (LPCC) and Mel Frequency Cepstral Coefficients (MFCC) are compared to extract representative features and develops hidden Markov model (HMM) for signal classification. At last, the experiment collects 100 heart sounds from 50 people to test the proposed algorithm.

RESULTSThe comparative experiments prove that LPCC is more suitable than MFCC for heart sound biometric, and by wavelet denoising in each piece of heart sound signal, the system achieves higher recognition rate than traditional GMM.

CONCLUSIONThose results show that this method can effectively improve the recognition performance of the system and achieve a satisfactory effect.

Algorithms ; Biometry ; Heart ; physiology ; Humans ; Markov Chains ; Models, Biological ; Phonocardiography ; methods ; Wavelet Analysis