Computer-assisted diagnosis for chronic heart failure by the analysis of their cardiac reserve and heart sound characteristics.

An innovative computer-assisted diagnosis system for chronic heart failure (CHF) was proposed in this study, based on cardiac reserve (CR) indexes extraction, heart sound hybrid characteristics extraction and intelligent diagnosis model definition. Firstly, the modified wavelet packet-based denoising method was applied to data pre-processing. Then, the CR indexes such as the ratio of diastolic to systolic duration (D/S) and the amplitude ratio of the first to second heart sound (S1/S2) were extracted.

[A troponin detection-combined study of rabbit experiment for evaluating cardiac fatigue].

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.

[Preliminary study of rabbit experiment modality for evaluating cardiac fatigue].

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.

[Analysis of the heart sound with arrhythmia based on nonlinear chaos theory].

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.

The third heart sound after exercise in athletes: an exploratory study.

The purpose of our study was to investigate the frequency of the third heart sound (S3) of athletes after exercise, and to determine whether the frequency and amplitude of S3 were related to cardiac function. The phonocardiogram exercise test (PCGET) was used in this study, and healthy volunteers consisting of 84 athletes (age 21.0±1.

Change of cardiac reserve during abnormal pregnancy and its evaluation.

Objective: To investigate the change of cardiac reserve during abnormal pregnancy and explore its evaluation methods.

Methods: Totally 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.

[A clinical study of cardiac reserve mobilizing condition for pregnant women].

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.

[Research on a new method and index for evaluating cardiac function of the athletes].

Objective: To explore the new indexes and new methods for the noninvasive measuring and evaluating cardiac function detection of the athletes.

Methods: Heart sound signals were sampled randomly from 81 students in physical education department (experiment group) and 41 students in general departments (control group) after completing designed workload during step-climbing exercise, the contrast study on heart rate, D/S ratio as well as the S1/S2 ratio of students from physical education and general department has been conducted.

Results: In the resting state, the physical education department students' heart rate and D/S ratio was 66 +/- 8.

Multi-center, multi-topic heart sound databases and their applications.

This paper describes a large resource of multi-center and multi-topic heart sound databases, which were based on the measured data from more than 9,000 heart sound samples (saved in WAV file format). According to different research topics, these samples were respectively stored in different folders (corresponding to different research topics and distributed over various cooperative research centers), most of which as subfolds were stored in a pooled folder in the principal center. According to different research topics, the measured data from these samples were used to create different databases.

[A basis for application of cardiac contractility variability in the Evaluation and assessment of exercise and fitness].

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.

[Clinical analysis of cardiac reserve function and outcome of preeclampsia.].

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 Medical 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 (20 cases), normal group 2 (26 cases) and normal group 3 (23 cases).

[A study on the four modes for transmitting heart sound signal].

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.

[Development of heart sound signal detection system based on USB interface].

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.

[Heart sound recognition algorithm based on PNN for evaluating cardiac contractility change trend].

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.

[Exercise ECG signal de-noising using unbiased risk estimate and wavelet transform].

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.

[Heart sound recognition algorithm based on mathematical morphology].

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.

[Study on medical diagnosis decision support system for heart diseases based on hybrid genetic algorithm].

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.

The internet-based knowledge acquisition and management method to construct large-scale distributed medical expert systems.

The Internet offers an unprecedented opportunity to construct powerful large-scale medical expert systems (MES). In these systems, a cost-effective medical knowledge acquisition (KA) and management scheme is highly desirable to handle the large quantities of, often conflicting, medical information collected from medical experts in different medical fields and from different geographical regions. In this paper, we demonstrate that a medical KA/management system can be built upon a three-tier distributed client/server architecture.

[A noninvasive method for measuring and evaluating cardiac reserve of athletes].

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.

A relative value method for measuring and evaluating cardiac reserve.

Background: Although a very close relationship between the amplitude of the first heart sound (S1) and the cardiac contractility have been proven by previous studies, the absolute value of S1 can not be applied for evaluating cardiac contractility. However, we were able to devise some indicators with relative values for evaluating cardiac function.

Methods: Tests were carried out on a varied group of volunteers.