The follow-up value of D/S ratio in CHF patients with treatment / 重庆医学

Objective To explore the follow-up value of phonocardiogram D/S ratio in CHF patients with treatment.Methods Forty-eight CHF patients who had never under-went regular treatment were collected in our hospital,given the regular anti-heart failure treatment for 3 months.NYHA heart failure classification,resting heart rate(RHR),and D/S ratio of phonocardiogram were recorded,six-minutes walk distance(6MWD),Left ventricular end diastolic diameter(LVEDd),the left ventricular ejection(LVEF) were tested before and after treatment.After 3-month treatment,the resting heart rate 65 times as the watershed,the patients were classified into two groups:one was up to standard,and the other was not up to standard.D/S ratio,RHR,6MWD,LVEDD,LVEF and the improvement of the heart function were compared between the two group.Results Exception the resting heart rate,the in-dicators had no significant improvement in the group of not up to standard compared with the before treatment,and D/S ratio, 6MWD,LVEF was improved significantly after three months treatment(P <0.05).In the group of up to standard,the D/S ratio was improved significantly after one months treatment(P <0.05),while after three months treatment all indicators were improved significantly(P <0.05).Comparison between the two groups,the RHR,D/S ratio were significantly improved(P <0.05 ),LVEF was significantly improved after three months treatment(P <0.05).At the same time,the D/S ratio,6MWD and NYHA classifica-tion of cardiac function was significant negatively correlated(P <0.05).Conclusion The D/S ratio could reflect heart functional im-provements in patients with CHF after anti-heart failure treatment,and it could reflect the heart functional improvement earlier and more significant in the group up to standard,it has a good clinic follow-up value in CHF patients with anti-heart failure treatment.

A troponin detection-combined study of rabbit experiment for evaluating cardiac fatigue / 生物医学工程学杂志

The objective of this study is to combine troponin and indicators of cardiac acoustics for synthetically evaluating cardiac fatigue of rabbits, analyzing exercise-induced cardiac fatigue (EICF) and exercise-induced cardiac damage (EICD). New Zealand white rabbits were used to conduct a multi-step swimming experiments with load, reaching an exhaustive state for evaluating if the amplitude ratio of the first to second heart sound (S1/S2) and heart rate (HR) during the exhaustive exercise would decrease or not and if they would be recovered 24-48 h after exhaustive exercise. The experimental end point was to complete 3 times of exhaustions or death from exhaustion. Circulating troponin I (cTnI) were detected from all of the experimental rabbits at rest [(0. 02±0. 01) ng/mL], which, in general, indicated that there existed a physiological release of troponin. After the first exhaustive swim, cTnI of the rabbits increased. However, with 24-hour rest, S1/S2, HR, and cTnI of the tested rabbits all returned toward baseline levels, which meant that the experimental rabbits experienced a cardiac fatigue process. After repeated exhaustion, overloading phenomena were observed, which led to death in 3 out of 11 rabbits, indicating their cardiac damage; the troponin elevation under this condition could be interpreted by pathological release. Evaluation of myocardial damage can not be based on the troponin levels alone, but can only be based on a comprehensive analysis.

Preliminary study of rabbit experiment modality for evaluating cardiac fatigue / 生物医学工程学杂志

This paper presents a preliminary study of rabbit experiment modality incorporating a new indicator for evaluating cardiac function changes, providing a basis for subsequent study of cardiac fatigue. Using only biochemical indicators, such as troponins, is difficult to make a distinction between exercise-induced cardiac fatigue (EICF) and exercise-induced cardiac damage (EICD). Therefore, some new indicators are needed to evaluate cardiac fatigue synthetically. In our study, we used New Zealand white rabbits to conduct a multi-step swimming experiments with load. We made the rabbits reach an exhaustive state to evaluate whether the amplitude ratio of the first to second heart sound (S1/S2) and heart rate (HR) during the exhaustive exercise would be decreased and whether they would be able to recover after the exhaustive exercise for 24 hours. During the first phase of swimming, S1/S2 and HR were increased, and then decreased at exhaustive state. They were recovered after the exhaustive exercise for 24 hours. Overloading led to deaths of three rabbis, and new phenomena from overloading and related to this kind of death were observed. The experiments proved that Multi-steps swimming experiments with loads by using New Zealand white rabbit is useful for studying cardiac fatigue and premonition of sudden cardiac death.

Analysis of the heart sound with arrhythmia based on nonlinear chaos theory / 生物医学工程学杂志

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.

Research and application of cardiac reserve data processing and information management system / 中国组织工程研究

BACKGROUND: Cardiac reserve indicators obtained under quiescent condition are used as evaluating index for cardiac reserve functions. However, most important aspect of cardiac dysfunction in heart failure is not the depressed cardiac performance noted at basal resting states, but rather the loss of cardiac reserve. OBJECTIVE: To develop a data processing and information management system for detecting cardiac reserve indicator with the widely used B mode ultrasound instrument in the ultrasonography field, and to provide guidance for B mode ultrasound instrument perfection. METHODS: General B mode ultrasound instrument as peripherals was connected with the pc by image acquisition card; ultrasound heart image diagnosis and management system including professional heart image acquisition and process and perfect data bank was develop. RESULTS AND CONCLUSION: An efficient and flexible mini picture archiving and communication system system was achieved, which realized image enhancement, geometric parameter measuring, convenient diagnosis report output, archive management and print function. Results demonstrated that with the powerful data process ability of PC, the system could improve the performance of the traditional ultrasound instrument in detecting cardiac reserve, which provide a powerful support for the further study.

A clinical study of cardiac reserve mobilizing condition for pregnant women / 生物医学工程学杂志

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.

A basis for application of cardiac contractility variability in the Evaluation and assessment of exercise and fitness / 生物医学工程学杂志

Cardiac contractility variability (CCV) is a new concept which is introduced in the research field of cardiac contractility in recent years, that is to say, there are some disparities between cardiac contractilities when heart contracts. The changing signals of cardiac contractility contain a plenty of information on the cardiovascular function and disorder. In order to collect and analyze the message, we could quantitatively evaluate the tonicity and equilibrium of cardiac sympathetic nerve and parasympathetic nerve, and the effects of bio-molecular mechanism on the cardiovascular activities. By analyzing CCV, we could further understand the background of human being's heritage characteristics, nerve types, the adjusting mechanism, the molecular biology, and the adjustment of cardiac automatic nerve. With the development of the computing techniques, the digital signal processing method and its application in medical field, this analysis has been progressing greatly. By now, the assessment of CCV, just like the analysis of heart rate variability, is mainly via time domain and frequency domain analysis. CCV is one of the latest research fields in human cardiac signals being scarcely reported in the field of sports medicine; however, its research progresses are of important value for cardiac physiology and pathology in sports medicine and rehabilitation medicine.

Clinical analysis of cardiac reserve function and outcome of preeclampsia / 中华妇产科杂志

Objective To investigate cardiac reserve function and pregnant results of preeclampsia.Methods Pregnant women chosen by randomized table and hospitalized in the department of obstetrics of the first affiliated hospital of Chongqing MedicaI University were involved in this study from January to December,2008.Sixty-nine cases of normal pregnant women were divided into 3 groups:normal group 1(20cases),normal group 2(26 cases)and normal group 3(23 cases).The normal group number 1 to number 3 were paired to gestational hypertension(20 cases),mild preeclampsia(26 cases)and severe preeclampsia (23 cases),respectively.The digital technique of heart sound signal processing WaS used to measure cardiac reserve function parameters including the heart rate(HR),the ratio of the amplitude of the first heart sound to the second heart sound(S1/S2)and the ratio of diastolic to systolic duration(D/S)of pregnant women.The pregnant results were also recorded.Results (1)The ratio of S1/S2 in the group of severe preeclampsia 4.5±3.2 was significantly bigher than the group of gestational hypertension 2.2±1.1 and normal group 32.2±1.1(P＜0.01).The ratio of D/S of the group of severe preeclampsia 1.1±0.3 Was significantly lower than the group of gestational hypertension 1.4±0.3 and normal group 31.4±0.2(P＜0.01).(2)All cases of the normal group number 1 to number 3 and the group of gestational hypertension were found the ratio of D/S≥1.00,whereas 1 case(1/26,4%)of the group of mild preeclampsia and 4 cases(4/23.17%)of the group of severe preeclampsia were found the ratio of D/S＜1.00.(3)The two cases of the pregnant wornen(including one woman died of cardiac arrest)with S1/S2＞5.00 and D/S＜1.00,who were in the group of severe preeclampsia,were sent to Intensive Care Unit after delivery.There were 4 cases(4/26,15%)and 6 cages(6/23,26%)of 1 minute Apgar score less than 7,7 cases(7/26,27%)and 6 cases(6/23,26%)sent to neonatal Intensive Care Unit,2 cases(2/26,8%)and 4 cases(4/23,17%)of neonatal death in the group of mild preeclampsia and in the group of severe preeclampsia,respectively.All newborns in the normal group number 1 to number 3 and the group of gestational hypertension were normal.Conclusions The cardiac reserve function of a pregnant woman with preeelampsia is decreased with the severity of preeclampsia and the parturient and neonatal results get worse.The distal technique of heart sound signal processing is a safe,harmless,simple and effective tool to measure cardiac reserve funotion of preeclampsia,and is worthy of widely used clinically.

A study on the four modes for transmitting heart sound signal / 生物医学工程学杂志

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.

Development of heart sound signal detection system based on USB interface / 生物医学工程学杂志

This paper introduces a type of heart sound recording, analysis and processing system based on USB interface. The system consists of high performance sensor sampling heart sounds, the preprocessing circuit, the A/D conversion module and the USB based high-speed computer communications interface. The experiments show that it is noninvasive, convenient, inexpensive and rapid in detecting the cardiac contractility of patients with heart disease as well as of healthy subjects. This system has provided a reliable technical platform for evaluating the cardiac contractility reserve.

Heart sound recognition algorithm based on PNN for evaluating cardiac contractility change trend / 生物医学工程学杂志

This paper discusses the recognition of heart sound for evaluating the cardiac contractility change trend, which includes heart sound samples recorded at different exercise condition. Especially, focused on the recognition of heart sound recorded after high intensity exercise workload. The algorithm proposed consisted of two correlative methods. The first was to recognize heart sound recorded at rest and after low intensity exercise workloads by probabilistic neural network and the second was to recognize heart sound recorded after high intensity exercise workloads based on the characteristic of heart sound. Both methods have two consecutive phases. Firstly, all peaks, including the peaks of both heart sounds and noise, are marked by a repetitive threshold detecting algorithm. Secondly, probabilistic neural network is employed to classify the peaks detected in the first phase into Si, S2, and noise. Finally, the performance of the algorithm was evaluated using 45 digital heart sound recordings including normal and abnormal heart sound, which were recorded at rest and after low intensity exercise workloads, and 28 digital heart sound recordings recorded after high intensity exercise workloads. The results showed that over 94% of heart sound samples were classified and recognized correctly. Moreover, the reasons for the wrong classification, of which omitting and misdetection are two main problems, are also discussed and solutions are proposed. So this method can be improved and refined in following studies. In conclusion, this algorithm is a reliable approach to detect and classify heart sounds, providing a solid basis for further heart sound analysis.

Exercise ECG signal de-noising using unbiased risk estimate and wavelet transform / 生物医学工程学杂志

In this paper a filtering method for EECG (Exercise ECG) signal is proposed which is based on wavelet transform (WT) and Stein's unbiased risk estimate (SURE). This algorithm was used to decompose original EECG signals into detail signals on different frequency bands by using WT and get different thresholds with SURE. According to EECG signal features and by using the above thresholds, the method amended several detail signals so that the main interferences in EECG signal can be removed efficiently. The authors also put forward two indexes to estimate the validity of such algorithms. Our experimental results demonstrate that this is an efficient de-noising method for EECG.

Implementation of physiological electrical signal transmission based on Bluetooth protocol / 医疗卫生装备

Bluetooth is a new widely accepted standard of short distance communication in personal area networks (PANs). By analyzing the communication process based on Bluetooth protocol and requirements of physiological electrical signal transmission, such operations are performed as the design of Bluetooth model for measurement of heart sound, the development of Bluetooth network communication library and the implementation of the model by programming.

Heart sound recognition algorithm based on mathematical morphology / 生物医学工程学杂志

In this paper, a new method was put forward for automatic recognition of the first heart sounds (S1) and the second heart sounds (S2). After the original heart sound signal was preprocessed, the heart sound envelope was extracted by using the mathematical morphology. Then on the heart sound envelope, S1 and S2 were recognized. Eighty heart sound samples collected were used for testing the algorithm. The accuracy of recognition was 86%, and was 100% for the normal heart sound. The result showed that the algorithm proposed in this paper had high performance, which could be used as a basis for further analysis of heart sound.

Study on medical diagnosis decision support system for heart diseases based on hybrid genetic algorithm / 生物医学工程学杂志

In this study, a medical diagnosis decision support system based on hybrid genetic algorithm has been established to support the diagnosis of five common heart diseases (coronary heart disease, rheumatic valvular heart disease, hypertensive heart disease, chronic cor pulmonale and congenital heart disease). A heart disease database consisting of 352 samples was used for constructing and testing the performance of system. Cross-validation of the experimental results indicate that the system we established shows high capability of classifying these five kinds of heart diseases, the mean accuracy of classification is as high as 90.6%, and the user accuracy and procedure accuracy of each disease are both above 85.0%, showing great application prospect of supporting heart diseases diagnosis in clinics.

Development of heart sounds teletransmission system based on GPRS / 医疗卫生装备

Heart sounds teletransmission is very important in telemedicine.The heart sounds are transmitted to the server which has been accessed to internet in custody center based on GPRS,then doctors analyze the heart sounds and transmit the conclusion to the consumer.

Implementation of serial communication between personal computer and C8051F000 in sampling of heart sound / 医疗卫生装备

This paper analyses the requirements of serial data communication interface between upper and lower hosts in a heart sound sampling system, and then introduces the system design scheme, schematic of hardware interface and source codes of upper and lower hosts. C8051F000 and personal computer adopted as the lower host and upper host respectively, C++ Builder and Windows API functions are also used to implement the applications.

Experimental study on an auditory method for analyzing DNA segments / 生物医学工程学杂志

To explore a new method for analyzing biological molecules that have already been sequenced, an experimental study on an auditory method was carried out. The auditory method for analyzing biological molecules includes audible representation of sequence data. Audible representation of sequence data was implemented by using a multimedia computer. Each mononucleotide in a DNA sequence was matched with a corresponding sound, i.e., a DNA sequence was "dubbed" in a sound sequence. When the sound sequence is played, a special cadence can be heard. In the audible representation experiment, special cadences of different exons can be clearly heard. The results show that audible representation of DNA sequence data can be implemented by using a multimedia technique. After a 5-time auditory training, subjects both in internal testing and external testing can obtain 93%-100% of judgment accuracy rate for the difference between two sound sequences of two different exons, thus providing an experimental basis for the practicability of this method. Auditory method for analyzing DNA segments might be beneficial for the research in comparative genomics and functional genomics. This new technology must be robust and be carefully evaluated and improved in a high-throughput environment before its implementation in an application setting.

The cardiac function assessment index and its measuring methods progress / 医疗卫生装备

This paper introduces several methods to measure cardiac function, including methods of FICK oxygen consumption, thermodilution, ultrasound cardiography, impedance cardiogram and the method with heart sound. Advantages and disadvantages of each method are discussed and compared. It is suggested that futural cardiac function evaluation approach be highly accurate or simply, noninvasive to meet different application requirements.