Deep Learning-Based Heart Sound Analysis for Left Ventricular Diastolic Dysfunction Diagnosis.

The aggravation of left ventricular diastolic dysfunction (LVDD) could lead to ventricular remodeling, wall stiffness, reduced compliance, and progression to heart failure with a preserved ejection fraction. A non-invasive method based on convolutional neural networks (CNN) and heart sounds (HS) is presented for the early diagnosis of LVDD in this paper. A deep convolutional generative adversarial networks (DCGAN) model-based data augmentation (DA) method was proposed to expand a HS database of LVDD for model training. Firstly, the preprocessing of HS signals was performed using the improved wavelet denoising method. Secondly, the logistic regression based hidden semi-Markov model was utilized to segment HS signals, which were subsequently converted into spectrograms for DA using the short-time Fourier transform (STFT). Finally, the proposed method was compared with VGG-16, VGG-19, ResNet-18, ResNet-50, DenseNet-121, and AlexNet in terms of performance for LVDD diagnosis. The result shows that the proposed method has a reasonable performance with an accuracy of 0.987, a sensitivity of 0.986, and a specificity of 0.988, which proves the effectiveness of HS analysis for the early diagnosis of LVDD and demonstrates that the DCGAN-based DA method could effectively augment HS data.

[Changes of some biochemical markers and cardiac function in New Zealand rabbits with chronic heart failure].

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 (n=15) and control group (n=5), injected with ADR and saline solution via 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 (P<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.

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±1.7 years; 62 males and 22 females) and 45 non-athletes (age 24.1±2.0 years; 33 males and 12 females) were enrolled. All subjects were healthy except one with a cardiac murmur without known cause. Immediately after exercise, S3 occurred in 21 athletes (25.0%) and 10 non-athletes (22.2%) during PCGET. There were very significant differences between pre-exercise and post-exercise in the frequency of S3 (P<0.01), and no significant difference between athletes and nonathletes (P>0.05). The prevalence of S3/S2≥1 was significantly (P<0.05) higher for the athlete group (47.1%) as compared to the non-athlete group (10%). Those results indicated that the emergence of S3 was an indicator of heart burden, and S3 after exercise in the athlete group was physiological. Our study showed that the amplitude of S3 had a very sensitive response to cardiac function reduction and S3/S2≥1 could eventually be used to assess cardiac fatigue states.

Change of cardiac reserve during abnormal pregnancy and its evaluation / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the change of cardiac reserve during abnormal pregnancy and explore its evaluation methods.</p><p><b>METHODS</b>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. 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.</p><p><b>RESULTS</b>Compared 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.</p><p><b>CONCLUSIONS</b>Cardiac 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.</p>

[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 +/- 8.7 and 2.04 +/- 0.33 respectively; general department students' heart rate and D/S ratio was 71 +/- 8.0 and 1.82 +/- 0.27 respectively. In the whole exercise, the physical education department students S1/S2 ratio was 7.34 +/- 4.04; general department students S1/S2 ratio was 5.22 +/- 2.38. CONCLUSION: Students from physical education department have higher level of cardiac reserve than that of students from general department. The method can evaluate cardiac reserve for athletes and general persons, and provide a new quantity evaluation index for selecting athletes and evaluating cardiac function of general persons.

[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). 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 higher than the group of gestational hypertension 2.2 +/- 1.1 and normal group 3 2.2 +/- 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 3 1.4 +/- 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 women (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 cases (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 preeclampsia is decreased with the severity of preeclampsia and the parturient and neonatal results get worse. The digital technique of heart sound signal processing is a safe, harmless, simple and effective tool to measure cardiac reserve function of preeclampsia, and is worthy of widely used clinically.

[Influence of dust catchers on PM10 emission characteristics of power plants].

Influence of dust catchers on PM10 emission characteristics was determined experimentally at the inlet and outlet of dust catchers at five different power plants. Electrical low pressure impactor (ELPI) with a sampling system, which consisted of an isokinetic sampler probe, pre-cut cyclone, two-stage dilution system and sample line to the instruments, were used to measure in situ. Size distribution is measured on the range from 0.03 microm to 10 microm in aerodynamic diameter. The results show that the testing system can be used widely for sampling of particulate matters from stationary sources. Before and after all the dust catchers, the particle number size distributions display the bimodal distribution which contained the submicron mode and the coarse mode with a peak around 0.07-0.12 microm and 0.76-1.23 microm, respectively. The minimum collection efficiency of the ESP and the bag-house both appear in the particle size range of 0.1-1 microm. In this size range, bag-house collection efficiency is higher than that of ESP. The ESP collection efficiencies of PM1 and PM2.5 based on the number concentration are also lower than that of PM10. The mass concentration of PM10 is mainly dominated by the particles which are larger than 1 microm, while the number concentration is dominated by the particles which are smaller than 0.1 microm. Mass and number size distributions measured after ESP can be seen that mass and number concentration of PM10 will increase obviously by rapping the last electric field. Furthermore, the ESP collection efficiencies based on the number concentration and mass concentration were both decreased by ESP rapping with different degree; and the maximum drop degree was appeared in PM1.

[Investigation on the nitrogen functionality of volatile through FTIR spectroscopy equipped with a long path distance gas cell].

Nitrogen functionalities of volatile of three different rank coals, namely TONGCHUAN lean coal, SHENMO bituminite and YIBIN anthracite, were studied by using Fourier transform infrared spectroscopy (FTIR) equipped with 16 m long path distance gas cell. The detection problem of low content of nitrogen in volatile was successfully solved because of the application of the long path distance gas cell. In the long path distance gas cell, the infrared penetrates the sample more times than in a normal gas cell. Results from the analysis of spectra obtained by FTIR show that there are four functionalities of nitrogen in volatile, including pyrrole-type nitrogen, pyrindine-type nitrogen, pyridine-N-oxide nitrogen, and nitrile nitrogen. Comparison of research results of nitrogen group between coal and volatile suggests that the difference in fate of nitrogen between volatile and coal results from the macromolecular nitrogen group of coal decomposition under the effect of temperature.