Research on classification of Korotkoff sounds phases based on deep learning / 中国胸心血管外科临床杂志

@#Objective     To recognize the different phases of Korotkoff sounds through deep learning technology, so as to improve the accuracy of blood pressure measurement in different populations. Methods     A classification model of the Korotkoff sounds phases was designed, which fused attention mechanism (Attention), residual network (ResNet) and bidirectional long short-term memory (BiLSTM). First, a single Korotkoff sound signal was extracted from the whole Korotkoff sounds signals beat by beat, and each Korotkoff sound signal was converted into a Mel spectrogram. Then, the local feature extraction of Mel spectrogram was processed by using the Attention mechanism and ResNet network, and BiLSTM network was used to deal with the temporal relations between features, and full-connection layer network was applied in reducing the dimension of features. Finally, the classification was completed by SoftMax function. The dataset used in this study was collected from 44 volunteers (24 females, 20 males with an average age of 36 years), and the model performance was verified using 10-fold cross-validation. Results     The classification accuracy of the established model for the 5 types of Korotkoff sounds phases was 93.4%, which was higher than that of other models. Conclusion     This study proves that the deep learning method can accurately classify Korotkoff sounds phases, which lays a strong technical foundation for the subsequent design of automatic blood pressure measurement methods based on the classification of the Korotkoff sounds phases.

Primary study on recognition of vascular stiffness based on wavelet scattering neural network / 生物医学工程学杂志

Cardiovascular disease is the leading cause of death worldwide, accounting for 48.0% of all deaths in Europe and 34.3% in the United States. Studies have shown that arterial stiffness takes precedence over vascular structural changes and is therefore considered to be an independent predictor of many cardiovascular diseases. At the same time, the characteristics of Korotkoff signal is related to vascular compliance. The purpose of this study is to explore the feasibility of detecting vascular stiffness based on the characteristics of Korotkoff signal. First, the Korotkoff signals of normal and stiff vessels were collected and preprocessed. Then the scattering features of Korotkoff signal were extracted by wavelet scattering network. Next, the long short-term memory (LSTM) network was established as a classification model to classify the normal and stiff vessels according to the scattering features. Finally, the performance of the classification model was evaluated by some parameters, such as accuracy, sensitivity, and specificity. In this study, 97 cases of Korotkoff signal were collected, including 47 cases from normal vessels and 50 cases from stiff vessels, which were divided into training set and test set according to the ratio of 8 : 2. The accuracy, sensitivity and specificity of the final classification model was 86.4%, 92.3% and 77.8%, respectively. At present, non-invasive screening method for vascular stiffness is very limited. The results of this study show that the characteristics of Korotkoff signal are affected by vascular compliance, and it is feasible to use the characteristics of Korotkoff signal to detect vascular stiffness. This study might be providing a new idea for non-invasive detection of vascular stiffness.

Correlation analysis of child and adolescent Korotkoff phase Ⅳ and Ⅴ sound with subclinical cardiovascular diseases in adulthood / 中华实用儿科临床杂志

Objective To examine the value of child and adolescent Korotkoff phase Ⅳ(K4)and Korotkoff phaseⅤ(K5)diastolic blood pressures for predicting subclinical cardiovascular disease(CVD)in adulthood.Methods The data was obtained from the Beijing Children Blood Pressure Study.A total of 3 198(1 700 males,53.2%)healthy children aged 6-18 years from 6 districts in Beijing in 1987 were selected.The physical examination process included measuring height,weight,and blood pressure.From a follow-up survey in 2010-2012,1 252 subjects were analyzed by the same measurements (height,weight and blood pressure)and also by using subclinical markers for vascular damage,including carotid intima-media thickness (cIMT)and carotid-femoral pulse wave velocity (cfPWV).Childhood hypertension at baseline and adulthood hypertension were diagnosed according to the China Guideline for Hypertension Prevention and Control issued in 2010.High cfPWV and high cIMT were defined in adults as having higher than age and gender-specific 75th percentile of cfPWV and cIMT.Pearson correlation coefficients were calculated to describe the association of K4 and K5 in childhood with systolic blood pressure(SBP),diastolic blood pressure(DBP),cfPWV, and cIMT in adulthood.Logistic regression was used to analyze the values of K4 and K5 to predict subclinical CVD in adulthood.Results The baseline mean value of K4 DBP was (66.4 ± 9.1)mmHg (1 mmHg＝0.133 kPa)and K5 DBP was (54.1 ± 11.1)mmHg.The prevalence rates of high-normal blood pressure were 9.4% with DBP measured by using K4,and 6.9% with DBP measured by using K5,respectively. The prevalence rates of hypertension were 11. 3% with DBP measured by using K4,and 8.4%with DBP measured by using K5.After adjustment for age and follow-up age,Pearson correlation analyses showed K4 DBP and K5 DBP in childhood were all significantly associated with adult SBP,DBP,cIMT,cfPWV in males and in females (all P＜0.05).K4 in childhood was better correlated with SBP,DBP,cIMT and cfPWV in adulthood than K5.With multi-factor logistic regression analysis,K4 was better than K5 in predicting CVD in adulthood after controlling gender and age.Further K4 was more effective in predicting cfPWV than cIMT.Conclusions There was a significant difference between K4 and K5 in Chinese children and adolescents. K4 in childhood was better correlated with CVD in adults than K5,and K4 is superior to K5 when using auscultator technique to measure DBP.

El corazón y sus ruidos cardíacos normales y agregados. Una somera revisión del tema / The heart, normal sounds and murmurs

Resumen Los ruidos cardíacos son la expresión sonora del cierre de las válvulas cardíacas, su funcionamiento fisiológico siempre es unidireccional, lo cual permite la correcta circulación de la sangre a través del circuito cardiovascular. La auscultación del área precordial permite la identificación de estos ruidos y sus matices en los 5 focos de auscultación. Existen ruidos que no son producidos por el cierre de las válvulas, por mencionar algunos podemos encontrar los llamados soplos y los ruidos de Korotkoff, ambos producidos por la interrupción del flujo natural de la sangre (flujo laminar) al convertirse en flujo turbulento cada vez que se encuentra una disminución del radio de los conductos por donde ésta circula.

Abstract The heart sounds are an audible expression of the heart valves closing. Their physiological function is always unidirectional, allowing the proper blood flow through the cardiovascular circuit. Listening - by auscultation- to the specific chest areas allows the identification of these sounds and nuances in the five auscultation areas. There are sounds that are not produced by the closing of the valves; to mention a few, we can find the so-called puffs and Korotkoff sounds, both produced by interrupting the natural flow of blood flow (laminar flow) that becomes a turbulent flow whenever there is a reduction of the radius of the conduits through which this the blood circulates.

Development of Acquisition of Korotkoff's Sound Signal Device / 医疗卫生装备

Objective To design a device sampling Korotkoff's sound signal and acquiring blood pressure based on Korotkoff theory.Methods The author sampled Korotkoff's sound signal via microphone,and then according the cuff pressure corresponding to signal appearance and disappearance,the author acquired SBP and DBP.At last,the author validated the creditability by contrasting with the results of auscultatory method.Results The difference of SBP and DBP is near nonexistence,the blood pressure data using this device is creditable.Conclusion The blood pressure can be measured using this device,and it can be used to further study the auto-measurement of blood pressure base on Korotkoff's sound theory.

Evaluation of Correlation between Automatic Ocillometric Sphygmomanometer and Standard Korotkoff Auscultatory Sphygmomanometer

BACKGROUND: Early diagnosis and treatment of hypertension is imperative to prevent the complications associated with this condition. The development of accurate and convenient methods of blood pressure measurement, therefore, is indispensible. At present, the JNC V has acknowledged the use of automatic sphygmomanometer that can be used without the help of someone else. We compared automatic oscillometric sphygmomanometers manufactured by Sein Electronics, korea(SE-7000 and SE-5000) with the standard Korotkoff auscultatory mercuy sphygmomanometer meter. The correlation between these two methods were calculated to determine whether these products could actually be used in clinical practice. This study was undertaken to ensure the clinical evaluation of these two products and standardization of an antomatic sphygmomanometer in korea before it is actually used. METHODS: The study included eighty-three patients, ranging in age from 14 to 81 years, who were admitted to Hanyang University Hospital in October, 1995. The blood pressure measured by the automatic oscillometric sphygmomanometer(SE-7000) in the right arm and was compared with that measured by the standard mercury sphygmomanometer(baumanometer) in the left arm. Also the blood pressure measured by the automatic oscillometric sphygmomanometer(SE-5000) at the wrist was compared by the baumanometer in the same side arm. The correlation between these methods were determined by the paired Student`s t-test and by the simple liner regression method. RESULTS: The p value of systolic blood pressure between two methods(SE-7000 and baumanometer) in the both arms was 0.896 and correlation coefficient was 0.8286. The p value of diastolic blood pressure between this two methods was 0.352 and correleation coefficient was 0.7455. The p value of systolic blood pressure between two methods(SE-5000 and baumanomter) by the arm and the wrist was 0.00018 and correlation coefficient was 0.8588, the p value of diastolic blood pressure between this two methods was 0.000048 and correlation coefficient was 0.5944. CONCLUSION: The blood pressure measured by the SE-5000 at the wrist was statistically different from that measured with the baumanometer in the arm. Further studies are necessary to use this product in clinical practice. However, the systolic and diastolic blood pressures measured with the SE-7000 in the arm were relatively similar to those measured by the baumanometer enabling this products to be effectively used in clinical practice.

Acupunctural Treatment for Hypertension / 全日本鍼灸学会雑誌

We have twice previously reported the results of our preliminary investigation regarding patients with hypertension. Recently, the focus of our interest has been on the blood pressure levels at the time of the third sound of korotkoff. We reported our findings regarding this topic in an oral presentation titled “Evaluation of acupunctural treatment in hypertensive patients” at the 9th Annual Central Japan Block Meeting of the Japanese Society of Acupuncture and Moxibustion Therapy.<br>Since then, we have accumulated further clinical experience regarding hypertensive patients. In this study, we investigated the third sound of korotkoff in patients diagnosed as borderline hypertension according to the WHO criteria for hypertension. The blood pressure during the third sound of korotkoff ranged from 100mmHg to 110mmHg in our patients. This difference in blood pressure noted during the decreasing phase of the blood pressure cycle may serve as a useful prognostic indicator in hypertensive patients.