OBJECTIVE: This article investigated the changes of some biochemical markers and cardiac function in chronic heart failure (CHF), and provided the basis for the diagnosis of CHF. METHODS: New Zealand rabbit CHF model was established using adriamycin (ADR). Twenty New Zealand rabbits were randomly divided into model group (=15) and control group (=5), injected with ADR and saline solution the ear vein respectively, 2 times a week, lasting for 8 weeks. After that, myocardial enzymes, carotid artery pressure, echocardiogram (ECG) and phonocardiogram (PCG) of all New Zealand rabbits were detected and recorded. RESULTS: Compared with control group, all parameters of the model group were changed significantly (<0.05). CONCLUSIONS CHF leads to myocardial damage in New Zealand rabbits, decreased systolic and diastolic function, cardiac reserve index can be used to assess cardiac function.
Animals ; Biomarkers ; analysis ; Blood Pressure ; Carotid Arteries ; physiopathology ; Chronic Disease ; Doxorubicin ; Electrocardiography ; Heart Failure ; chemically induced ; physiopathology ; Myocardium ; enzymology ; Phonocardiography ; Rabbits ; Random Allocation

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

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

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

In this paper, a new method based on the nonlinear chaos theory was proposed to study the arrhythmia with the combination of the correlation dimension and largest Lyapunov exponent, through computing and analyzing these two parameters of 30 cases normal heart sound and 30 cases with arrhythmia. The results showed that the two parameters of the heart sounds with arrhythmia were higher than those with the normal, and there was significant difference between these two kinds of heart sounds. That is probably due to the irregularity of the arrhythmia which causes the decrease of predictability, and it's more complex than the normal heart sound. Therefore, the correlation dimension and the largest Lyapunov exponent can be used to analyze the arrhythmia and for its feature extraction.
Arrhythmias, Cardiac ; diagnosis ; physiopathology ; Heart Sounds ; physiology ; Humans ; Logistic Models ; Nonlinear Dynamics ; Phonocardiography ; Signal Processing, Computer-Assisted

OBJECTIVETo investigate the change of cardiac reserve during abnormal pregnancy and explore its evaluation methods.

METHODSTotally 96 women with abnormal pregnancies (AP group), 356 women with normal pregnancies (NP group), and 100 women of childbearing age (CBA group) were monitored by the exercise cardiac contractility monitor (ECCM). Phonocardiogram of participants at resting status was recorded by ECCM. The amplitude of first heart sound (S1), the amplitude of second heart sound (S2), cardiac cycle, diastolic duration (D), and systolic duration (S) were detected and then the S1/S2 ratio,the D/S ratio, and heart rate (HR) were calculated.

RESULTSCompared with the CBA group, S1/S2 ratio and HR were significantly higher and D/S was significantly lower in both AP group and NP group (all P<0.001). Compared with the NP group, S1/S2 ratio and HR were significantly higher in AP group and D/S was significnatly lower (all P<0.001). A D/S ratio less than 1.1 or S1/S2 ratio higher than 1.8 was associated with higher risk of poor pregnancy outcomes. Among four common pregnancy-associated abnormalities, the level of cardiac reserve was lowest in eclampsia, followed by twins, gestational diabetes mellitus, and gestational hypertension.

CONCLUSIONSCardiac reserve is mobilized during pregnancy, and is especially during the abnormal pregnancies due to the heavy cardiac burden. S1/S2 ratio, D/S ratio, and HR are useful in evaluating the cardiac reserve during abnormal pregnancy.

Adult ; Female ; Heart ; physiopathology ; Humans ; Phonocardiography ; Pregnancy ; Pregnancy Complications ; physiopathology ; Pregnancy Outcome ; Young Adult

Auscultation, the act of listening for heart sounds to aid in the diagnosis of various heart diseases, is a widely used efficient technique by cardiologists. Since the mechanical prosthetic heart valves are widely used today, it is important to develop a simple and efficient method to detect abnormal mechanical valves. The study on five different mechanical valves showed that only the case of perivalvular leakage could be detected by spectral estimation. Though it is possible to classify different mechanical valves by using time-frequency components of the signal directly, the recognition rate is merely 84%. However, with the improved local discriminant bases (LDB) algorithm to extract features from heart sounds, the recognition rate is 97.3%. Experimental results demonstrated that the improved LDB algorithm could improve classification rate and reduce computational complexity in comparison with original LDB algorithm.
Algorithms ; Heart Sounds ; physiology ; Heart Valve Diseases ; physiopathology ; surgery ; Heart Valve Prosthesis ; Heart Valves ; physiopathology ; Humans ; Pattern Recognition, Automated ; Phonocardiography ; Signal Processing, Computer-Assisted ; Spectrum Analysis ; 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

Exercise Test ; Female ; Heart Sounds ; physiology ; Humans ; Male ; Phonocardiography ; methods ; Pregnancy ; Stress, Physiological ; physiology ; Young Adult

This study was conducted on the basis of informed consent of subjects and was approved by the ethical review committee concerned. 527 pregnant women voluntarily participated in this project for the investigation of cardiac reserve mobilizing condition. Using the digital technique of heart sound signal processing, we measured the heart rate (HR), the ratio of the first heart sound to the second heart sound (S1/S2)and the ratio of diastolic to systolic duration (D/S) during pregnancy. There was significant difference of HR and S1/S2 between the group of non-pregnant (G1), the group of 28-36 pregnant weeks (G2), and the group of 37-42 pregnant weeks (G3) (HR, S1/S2: G1 vs G2, G1 vs G3: P < 0.01). HR of the pregnant women increased with the increase of pregnant weeks. D/S decreased with the increase of pregnant weeks. There was significant difference of D/S between G1, G2, and G3 (G1 vs. G2: P < 0.01; G1 vs. G3: P < 0.01). There was also significant difference of D/S between G2 and G3 (G2 vs. G3: P < 0.05). Everybody in the non-pregnant women group was found to have D/S > or = 1.30; 64.33% of pregnant women were found to have 1.00 < D/S < 1.30, whereas 3.05% of pregnant women were found to have D/S < 1.00. These data revealed that the heart burden of the pregnant woman increased with the increase of pregnant weeks and the mobilization of cardiac reserve.
Adult ; Female ; Heart ; physiology ; Heart Rate ; physiology ; Heart Sounds ; Humans ; Phonocardiography ; methods ; Pregnancy ; physiology ; Pregnancy Trimester, Third ; physiology ; Signal Processing, Computer-Assisted ; Young Adult