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Articles de revues sur le sujet "Cardiovascular system – ultrasonography"
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LAZARIDIS, LJ, et EA KIOSSIS. « Applications of ultrasonography in ruminants (I) : A Review. » Journal of the Hellenic Veterinary Medical Society 61, no 4 (22 mars 2018) : 339. http://dx.doi.org/10.12681/jhvms.14907.
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In the middle of 1960s ultrasonography entered the veterinary clinical practice of large animals, almost one decade after the introduction in medicine. First ultrasonography was used to approach problems of the ovine genital system. Overtime, new applications were developed and the use of ultrasonography in large animal medicine was intensified. In the everyday veterinary clinical practice B-mode ultrasonographic devices are mainly used, with simple or convex linear array probes, with a frequency of 3.0 MHz to 7.5 MHz, while sector probes are also used. The adequate knowledge of the anatomy of the region, the appropriate restraint of the animal and a previous good clinical examination are the main prerequisites to conduct an ultrasonographic examination. In ruminants ultrasonographic examination can be applied in mainy systems. In respiratory system ultrasonography is used to evaluate the general condition of the thoracic cavity, with main diagnosticai applications in pulmonary emphysema, bronchopneumonia and aspiration pneumonia. In cardiovascular system ultrasonography contributes efficiently to the examination of the heart and the vessels. Doppler devices offer the opportunity of better estimation of some blood parameters. In the last two decades the use of ultrasonography has been propagated widely to approach problems associated to the digestive system of the ruminants and to evaluate the general condition of their peritoneal cavity. Ultrasonography is a very useful diagnostic tool to evaluate traumatic reticuloperitonitis and distension of the cecum. In cattle ultrasonographic examination of some organs, such as liver, spleen and pancreas, offers an opportunity to estimate changes in their size, contour and their position in the abdomen comparatively to their adjacent organs. Changes in the normal echotexture image are in most cases a sign of pathological conditions. Ultrasonography is useful in calves for the estimation of the condition of their umbilicus. At their first week of life, contributes to confront better some conditions such as omphalophlebitis, omphaloarteritis and omphalolourachitis. In the ruminants' urinarysystem ultrasonography is used to approach cases of urolithiasis along to the deferent section, cases with rupture of the urinary tract or cases with the presence of a mass. Application of ultrasonography in the bovine's musculoskeletal system, which has been researched thoroughly at the last two decades, offers an opportunity to image in a better way the joints which are covered by huge muscles. The anatomical and tissue function can be estimated in real time and the general condition of the animal can be evaluated. New advantages of ultrasonography are being researched, with main purpose the use of this technology as much as possible. Ultrasonography is a very effective imaging means in the service of the clinical veterinarian, which offers him the opportunity to examine in real time the area he desires in ruminants, but it doesn't replace the clinical examination.
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Dincer, Emre, Hamza Özer, Sevilay Topçuoğlu et Güner Karatekin. « Ultrasonography Causes Agitation and Pain Leading to Hemodynamic Disturbance in Neonates : A Prospective Observational Study ». Children 10, no 2 (10 février 2023) : 347. http://dx.doi.org/10.3390/children10020347.
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Background: Ultrasonography is widely used in neonatological practice and studies investigating the hemodynamic effects of various treatment protocols or clinical situations. On the other hand, pain causes changes in the cardiovascular system; so, in the case of ultrasonography leading to pain in neonates, it may cause hemodynamic alterations. In this prospective study, we evaluate whether ultrasonographic application causes pain and changes in the hemodynamic system. Methods: Newborns undergoing ultrasonographic examination were enrolled in the study. Vital signs, cerebral and mesenteric tissue oxygenation (StO2) levels, and middle cerebral artery (MCA) Doppler measurements were recorded, and NPASS scores were calculated before and after ultrasonography. Results: We enrolled 39 patients in the study. After ultrasonography, Neonatal Pain, Agitation, and Sedation Scale (NPASS) scores were significantly higher (p < 0.01), and all vital signs (heart rate, respiratory rate, SpO2, diastolic and systolic blood pressure; p = 0.03; p < 0.01, p < 0.01, p < 0.01, p = 0.02, p = 0.03, respectively) were altered. Cerebral (p = 0.008) and mesenteric (p = 0.039) StO2 levels were significantly lower in the whole study group, MCA end-diastolic velocity decreased (p = 0.02), and the resistive index (p = 0.03) increased in patients whose NPASS score was >7 after ultrasonography. Conclusions: This study is the first to show that ultrasonography may cause pain in newborn patients, and alters vital signs and hemodynamic parameters. Therefore, precautions should be taken to protect newborn babies from pain during ultrasound applications, as they are already exposed to many noxious stimuli. Furthermore, pain scores should be considered in studies using ultrasonography and evaluating hemodynamic parameters to increase the reliability of the studies.
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Demková, Katarína, Tibor Varga et Ján Tokarčík. « Association of non-alcoholic fatty liver disease with cardiac structural impairment ». Gastroenterologie a hepatologie 76, no 4 (31 août 2022) : 341–46. http://dx.doi.org/10.48095/ccgh2022341.
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Summary: Non-alcoholic fatty liver disease encompasses a spectrum of pathologic entities ranging from liver steatosis through non-alcoholic steatohepatitis and fibrosis to cirrhosis of the liver. Patients with non-alcoholic fatty liver disease have a higher incidence of coronary artery disease, cardiovascular events due to atherosclerosis, both ischemic and haemorrhagic strokes, thromboembolic events, conduction system disorders, left ventricular dysfunction, and also cardiovascular mortality. Non-alcoholic fatty liver disease is also associated with structural abnormalities of the myocardium and valves. Non-alcoholic steatohepatitis develops in about 8–20% of obese patients with simple hepatic steatosis. The disease tends to progress and may be poorly controlled therapeutically. Non-alcoholic steatohepatitis increases the risk of mortality from cardiovascular disease by 2.1-fold and the risk of mortality from any cause by 2.3-fold. The inflammatory process in the liver may represent a major determinant of systemic complications in people with non-alcoholic fatty liver disease, so its assessment could be useful for cardiovascular risk assessment. Due to the documented association between the severity of hepatic steatosis assessed by ultrasonography and coronary or carotid atherosclerosis, ultrasonographic examination of the liver may be helpful in identifying people at high cardiovascular risk. The present case report confirms the importance of echocardiographic screening for structural and functional cardiac abnormalities in patients with chronic non-alcoholic steatohepatitis in order to initiate early treatment and improve their prognosis. Key words: non-alcoholic fatty liver disease – ultrasonography – echocardiography – screening
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BENEDETTO, FRANCESCO ANTONIO, FRANCESCA MALLAMACI, GIOVANNI TRIPEPI et CARMINE ZOCCALI. « Prognostic Value of Ultrasonographic Measurement of Carotid Intima Media Thickness in Dialysis Patients ». Journal of the American Society of Nephrology 12, no 11 (novembre 2001) : 2458–64. http://dx.doi.org/10.1681/asn.v12112458.
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Abstract. High-resolution carotid ultrasonography is considered a fundamental technique for the investigation of the vascular system. However, it is still very unclear whether ultrasonographic studies of carotid arteries are useful for the prediction of cardiovascular events in patients with end-stage renal disease. The prediction power of carotid ultrasonography for all-cause and cardiovascular mortality was tested in a cohort of 138 patients receiving chronic dialysis treatment (91 receiving hemodialysis treatment and 47 receiving continuous ambulatory peritoneal dialysis treatment; follow-up, 29.8 ± 15.0 mo), and the relationship between this parameter and alterations in left ventricular mass (LVM) and geometry was examined. On univariate analysis, intima media thickness (IMT) was directly related to LVM as well as to the absolute and relative thicknesses of LV walls but independent of LV end-diastolic volume. Data analysis based on LV geometry patterns revealed that patients with concentric hypertrophy were those with the highest IMT. The internal diameter of the common carotid artery (DCCA) was also related to concentric hypertrophy, but the strength of this relationship was of borderline significance (P= 0.06). During the follow-up period, 63 patients died: 32 (51%) of them of cardiovascular causes. IMT was significantly higher (P= 0.006) in patients who died of cardiovascular causes (1.10 ± 0.21 mm) than in patients who survived (0.99 ± 0.24 mm), In a Cox regression model, this parameter turned out to be an independent predictor of cardiovascular death, and it retained an independent effect in a model that included LVM. Treatment modality failed to independently predict this outcome. The risk of cardiovascular death was progressively higher from the first IMT tertile onward. DCCA failed to predict cardiovascular outcomes. IMT in dialysis patients is associated with LV concentric hypertrophy and is an independent predictor of cardiovascular death. IMT may be usefully applied for risk stratification in the dialysis population.
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He, Wei, Songnong Li, Hanguang Xiao, Chuanxiang Yu et Haitao Lin. « AN EMBEDDED MICROPROCESSOR UNIT-BASED PORTABLE NONINVASIVE ARTERIOSCLEROSIS DETECTING SYSTEM AND ITS EXPERIMENTAL STUDY ». Biomedical Engineering : Applications, Basis and Communications 25, no 06 (décembre 2013) : 1350051. http://dx.doi.org/10.4015/s1016237213500518.
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Pulse wave velocity (PWV) and arterial stiffness index (ASI) are considered as the independent predictors of cardiovascular morbidity and mortality — the effective methods to assess arterial stiffness. A portable noninvasive arterial elasticity detecting system (PNAEDS) was developed based on embedded microprocessor unit. This system can simultaneously measure PWV, ASI and other arteriosclerosis critical risk factors. Algorithm of main critical risk factors and design of the system were described in detail. To verify the performance of the PNAEDS, laboratory prospective validation and clinical trial were launched. Reliability of the system and superiority of improved PWV algorithm were validated in laboratory prospective validation. Subsequently, the authors implemented a comparative clinical trial (60 subjects) between measured values obtained by the PNAEDS and carotid intima-media thickness (IMT) value that Doppler ultrasonography measured. Clinical testing results revealed that the measurement with the PNAEDS was consistent with the measurement with the Doppler ultrasonography. In summary, the system may be used to reliably determine the arteriosclerosis critical risk factors and to the early diagnosis and prevention of cardiovascular disease.
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Kokhanenko, Nikolay Yurevich, Yuriy Nikolaevich Shiryajev, Andrey Lvovich Lugovoy, Sergey Alexandrovich Danilov et Lekso Zurabovich Gurtskaya. « Features of pathogenesis, clinical course and diagnosis of acute cholecystitis of patients with decompensated cardiovascular diseases ». Pediatrician (St. Petersburg) 6, no 4 (15 décembre 2015) : 62–68. http://dx.doi.org/10.17816/ped6462-68.
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The work presents the features of pathogenesis, clinical course and diagnosis of acute cholecystitis of patients with decompensated cardiovascular diseases have been submitted in this report. The main diseases of cardiovascular system that affects the prognosis of acute cholecystitis have been set off. The sufficient detailed is written about the criteria for patients at risk. Listed severe somatic diseases, which are frequent in older patients being treated in surgical hospitals. The pathogenetic link between inflammatory disease of the gallbladder and cardiovascular system has been explained. The problem of mutual deterioration between acute cholecystitis and different manifestations of coronary artery disease has been reviewed. The noting widespread introduction of new non-invasive methods (ultrasonography, computer tomography and magnetic resonance tomography) and invasive (endovideosurgery) diagnostics. Detailed characteristics of such instrumental techniques as ultrasonography, magnetic resonance cholangiopancreatography, magnetic tomography, endoscopic retrograde cholangiopancreatography, diagnostic laparoscopy has been given. The role of specific biochemical markers of necrosis has been showed: creatinephosphokinase, its heart fraction, troponin test. Possible changes on the electrocardiogram of patients with acute cholecystitis and reasons for their appearance have been described. Detailed recommendations for the identification of acute myocardial infarction of patients with acute cholecystitis using markers of myocardial damage have been given.
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Bastrikov, O. Yu, E. A. Grigoricheva, V. V. Belov et V. V. Milegov. « Association of arterial stiffness and cardiovascular system remodeling in patients with hypertension ». Kazan medical journal 95, no 4 (15 août 2014) : 485–90. http://dx.doi.org/10.17816/kmj1827.
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Aim. To study the indices of arterial wall local stiffness and it association with structural and functional parameters of cardiovascular system remodeling in hypertensive patients. Methods. Cross-sectional population study included 213 industrial workers, among them 106 patients with stage I-II hypertension and 107 healthy individuals. The stage of arterial hypertension and additional cardiovascular risk category was performed in accordance with national guidelines. All patients underwent echocardiography, carotid arteries ultrasonography, including arterial stiffness evaluation. Results. In patients with hypertension, significant association of arterial wall stiffness indices and «intima-media» complex thickness (total impact of 91%) and echocardiographic parameters describing the left heart chambers volume were revealed. The fact of identifying the relatively high rate of altered arterial wall stiffness parameters, as well as its association with «intima-media» complex thickness in healthy individuals with normal blood pressure (total impact of 81%) may suggest that vascular wall rigidity change may premise vascular remodeling. Conclusion. Arterial wall stiffness indices may be a marker of effective control of risk factors in individuals with normal blood pressure and effect of drug therapy in patients with hypertension.
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Kovaitė, Milda, Žaneta Petrulionienė, Ligita Ryliškytė, Jolita Badarienė, Alma Čypienė, Vilma Dženkevičiūtė et Aleksandras Laucevičius. « Relationship of arterial wall parameters to cardiovascular risk factors and cardiovascular risk assessed by SCORE system ». Medicina 43, no 7 (17 juin 2007) : 529. http://dx.doi.org/10.3390/medicina43070067.
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Objective. To investigate the relationship of arterial wall parameters (flow-mediated dilatation of the brachial artery, augmentation index, pulse wave velocity, stiffness index, carotid intima-media thickness) to conventional cardiovascular risk factors and cardiovascular risk assessed by SCORE system. Material and methods. A total of 209 subjects aged 40–65 years without clinically overt cardiovascular disease were examined. Parameters of arterial stiffness were obtained by two methods: augmentation index and carotid-radial pulse wave velocity by applanation tonometry and stiffness index by the means of finger photoplethysmography. Flow-mediated dilatation of the brachial artery, reflecting endothelial function, and carotid intima-media thickness was determined using a high-resolution B-mode ultrasonography. Results. Age and the presence of diabetes strongly influenced all parameters of the arterial wall (diabetes was not independent predictor when evaluating augmentation index). Mean arterial pressure and gender were independent predictors for arterial stiffness parameters – carotid-radial pulse wave velocity and augmentation index. Flow-mediated dilatation was strongly dependent on the diameter of the brachial artery, age, and body mass index. Using logistic regression, it was found that pulse wave velocity (P=0.014), intima-media thickness (P=0.004), and flow-mediated dilatation (P=0.020) were important parameters dividing subjects to the groups of increased (³5%) and low (<5%) cardiovascular risk assessed by SCORE system. The cutoff values for intima-media thickness and pulse wave velocity were 0.078 cm and 8.95 m/s, respectively. Conclusions. Arterial wall parameters are closely associated with conventional risk factors; they are influenced by age and the presence of diabetes. Arterial stiffness parameters are also influenced by mean arterial pressure; high-density lipoprotein cholesterol has influence on carotid intima-media thickness. Cutoff values for carotid intima-media thickness and carotid-radial pulse wave velocity could help to discriminate patients with increased cardiovascular risk.
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Oltean-Péter, Balázs, István Kovács, Monica Chițu et Imre Benedek. « The Role of Carotid Ultrasonography in Patients with High Risk of Atherosclerosis ». Journal of Interdisciplinary Medicine 3, no 4 (1 décembre 2018) : 229–33. http://dx.doi.org/10.2478/jim-2018-0029.
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Abstract Atherosclerosis is a systemic disease that most often affects the carotid arteries. Being usually asymptomatic in its early stages, it is diagnosed only in advanced stages, when treatment is more difficult and prognosis is poor. Carotid ultrasound (US) is the most commonly used method for diagnosing carotid artery disease and represents a proper method for screening in patients with cardiovascular (CV) risk factors. This paper shows the methodology and necessity of carotid imaging methods in patients at high risk of developing atherosclerotic lesions. We also review the findings that underline the need of carotid screening in patients with ischemic heart disease or with ischemic arteriopathy, showing that the carotid arteries are like ‘mirrors’ of the arterial system, which need to be assessed in every patient with CV risk factors, regardless of the presence or absence of symptoms.
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Kweon, Ye-Na, Hae-Jin Ko, A.-Sol Kim, Hye-In Choi, Ji-Eun Song, Ji-Yeon Park, Sung-Min Kim, Hee-Eun Hong et Kyung-Jin Min. « Prediction of Cardiovascular Risk Using Nonalcoholic Fatty Liver Disease Scoring Systems ». Healthcare 9, no 7 (15 juillet 2021) : 899. http://dx.doi.org/10.3390/healthcare9070899.
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This study aimed to determine whether nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for CVD and to identify the most useful NAFLD diagnostic tool for predicting CVD. Data from a total of 23,376 Korean adults without established CVD were analyzed. Cardiovascular risk was calculated using the Framingham Risk Score (FRS) 2008. The presence of NAFLD was defined as moderate-to-severe fatty liver disease diagnosed by ultrasonography. Scores for fatty liver were calculated using four NAFLD scoring systems (Fatty Liver Index, FLI; Hepatic Steatosis Index, HSI; Simple NAFLD Score, SNS; Comprehensive NAFLD Score, CNS), and were compared and analyzed according to cardiovascular risk group. Using the FRS, 67.4% of participants were considered to be at low risk of CVD, 21.5% at intermediate risk, and 11.1% at high risk. As the risk of CVD increased, both the prevalence of NAFLD and the score from each NAFLD scoring system increased significantly (p < 0.001). In the unadjusted analysis, the CNS had the strongest association with high CVD risk; in the adjusted analysis, the FLI score was most strongly associated with high CVD risk. Fatty liver is an important independent risk factor for CVD. Therefore, the available NAFLD scoring systems could be utilized to predict CVD.
Thèses sur le sujet "Cardiovascular system – ultrasonography"
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Ninno, Milena Almeida Prado. « Dopplervelocimetria do fluxo normal da valva tricúspide fetal entre 11 e 13 semanas e 6 dias de gestação ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5139/tde-27052010-164819/.
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Objetivo: Determinar os valores dopplervelocimétricos normais do fluxo através da valva tricúspide em gestações únicas, entre 11 e 13 semanas e seis dias. Examinar a reprodutibilidade dos parâmetros avaliados e sua correlação com variáveis clínicas maternas e obstétricas. Métodos: Estudo prospectivo envolvendo 166 gestações únicas, com desfecho normal, examinadas entre 11 e 13 semanas e seis dias, no período de fevereiro de 2006 a agosto de 2008. Foram aferidas as velocidades máximas das ondas E e A, duração do ciclo cardíaco completo e sua fase diastólica e calculadas as relações onda E/onda A e diástole/ciclo. Os valores normais foram descritos pelas respectivas médias e desvio-padrão. Para análise da reprodutibilidade desses parâmetros foi calculado o coeficiente de correlação intra-classes em 12 casos examinados por dois examinadores. Regressão linear simples e multivariada foram empregadas para examinar a correlação dos parâmetros dopplervelocimétricos entre si e com a idade gestacional, a medida da translucência nucal e variáveis maternas. Resultados: Neste intervalo gestacional, os valores normais encontrados foram: onda E, 25 (± 4,6) cm/s; onda A, 42,9 (± 5,9) cm/s; relação E/A, 0,58 (± 0,07); ciclo cardíaco, 390 (± 21,1) ms; diástole, 147 (± 18) ms; relação diástole/ciclo, 0,38 (± 0,04). Entre as variáveis dopplervelocimétricas, foi observada correlação significativa entre o ciclo cardíaco e diástole (r=0,53; p<0,0001), diástole e onda A (r=-0,15; p=0,05), ondas E e A (r=0,77; p<0,0001), onda E e relação D/C (r=0,16; p=0,04), onda A e relação diástole/ciclo (r=-0,17; p=0,03). Todas as variáveis, exceto a velocidade da onda A, correlacionaram-se positivamente com a idade gestacional. Não foi observada correlação significativa das variáveis com a medida da translucência nucal, e, na comparação com as variáveis maternas, apenas a onda E e a idade materna apresentaram correlação significativa (r=-0,18, p=0,04). Os coeficientes de correlação intra-classes para a avaliação interobservador e intra-observador (examinadores um e dois) foram: onda E = 0,53 (0,53 e 0,64); onda A = 0,45 (0,46 e 0,49); ciclo cardíaco = 0,70 (0,79 e 0,84) e diástole = 0,63 (0,85 e 0,82). Conclusão: O presente estudo estabeleceu os valores normais dos parâmetros dopplervelocimétricos do fluxo através da valva tricúspide e demonstrou que tais parâmetros, com exceção da onda A, correlacionaram-se de forma positiva com a idade gestacional, e apresentaram reprodutibilidade boa/moderada.Objective: To establish the measurements of normal tricuspid valve flow velocities at 11 to 13 weeks and 6 days to determine E-wave, A-wave, E/A ratio, cardiac cycle length, diastole length, diastole/cardiac cycle ratio, and their relationship with gestational age, nuchal translucency thickness, the characteristics of the study population, and to assess the reproducibility of flow measurements. Methods: Between February, 2006, and August, 2008, a total of 166 women with a singleton normal pregnancy between 11 and 13 + 6 weeks of gestation consented to participate in the study. Analysis of the waveforms consisted of calculation of peak velocity (cm/s) of the E-wave and A-wave, E-wave/A-wave ratio, cardiac cycle length (ms), diastole length (ms) and diastole/cardiac cycle ratio. To evaluate the intraobserver and interobserver agreement, a subgroup of 12 patients, chosen randomly, was examined twice by each examiner. For descriptive analysis of the results were calculated average and standard deviation. Simple and multivariate linear regression was used to establish the correlation between dopplervelocimetry among parameters and with gestational age, nuchal translucency thickness and the characteristics of the study population. Results: The average (± standard deviation) for transtricuspid flow-velocities waveforms parameters were: E-wave 25 (± 4.6) cm/s; A-wave 42.9 (± 5.9) cm/s; E/A ratio 0.58 (± 0.07); cardiac cycle length 390 (± 21.1) ms; diastole length 147 (± 18) ms; diastole/cardiac cycle length 0,38 (± 0.04). A statistically significant linear increase relative to gestational age was established for all parameters, except A-wave. Nuchal translucency thickness was not correlated with any parameter. A statistically significant negative regression coefficient was established for E-wave to maternal age (r=-0,18, p=0,04). A statistically significant relationship was established between: cardiac cycle length and diastole length (r=0.53; p<0.0001); diastole length and A-wave velocity (r=-0.15; p=0.05); E-wave and A-wave velocities (r=0.77; p<0.0001); E-wave velocity and D/C ratio (r=0.16; p=0.04); A-wave velocity and D/C ratio (r=-0.17; p=0.03). The intraclass correlation coeficients of interobserver and intraobsever evaluations (examiners 1 and 2) were: Ewave = 0.53 (0.53 and 0.64); A-wave = 0.45 (0.46 and 0.49); cardiac cycle = 0.70 (0.79 and 0.84) and diastole= 0.63 (0.85 and 0.82). Conclusions: These data determine normal parameters for tricuspid valve dopplervelocimetry and shows that these parameters, except A-wave, have positive correlation with gestational age, and good/moderate reproducibility.
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Koegelenberg, Suretha. « Application of laser doppler vibrocardiography for human heart auscultation ». Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86649.
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Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: This thesis investigates the feasibility of the laser Doppler vibrometer (LDV) for use in the autonomous auscultation of the human heart. As a non-contact measurement device, the LDV could become a very versatile biomedical sensor. LDV, stethoscope, piezoelectric accelerometer (PA) and electrocardiogram (ECG) signals were simultaneously recorded from 20 volunteers at Tygerberg Hospital. Of the 20 volunteers, 17 were confirmed to have cardiovascular disease. 3 patients with normal heart sounds were recorded for control data. The recorded data was successfully denoised using soft threshold wavelet denoising and ensemble empirical mode decomposition. The LDV was compared to the PA in common biomedical applications and found to be equally accurate. The heart sound cycles for each participant were segmented using a combination of ECG data and a simplicity curve. Frequency domain features were extracted from each heart cycle and input into a k-nearest neighbours classifier. It was concluded that the LDV can form part of an autonomous, non-contact auscultation system.
AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die haalbaarheid daarvan om die laser Doppler vibrasiemeter (LDV) vir die outonome beluistering van die menslike hart te gebruik. As 'n kontaklose meettoestel kan die LDV werklik 'n veelsydige biomediese sensor word. Twintig vrywilligers by die Tygerberg Hospitaal se LDV-, stetoskoop-, piësoelektriese versnellingsmeter (PV)- en elektrokardiogram (EKG) seine is gelyktydig opgeneem. Uit die 20 vrywilligers was daar 17 bevestigde gevalle van kardiovaskulêre siektes. Die data van drie pasiënte met normale hartklanke is as kontroledata opgeneem. Geraas is suksesvol uit die opgeneemde data verwyder deur 'n kombinasie van sagtedrempelgolf en saamgestelde empiriese modus ontladingstegnieke. Die LDV was vergelyk met die PV vir algemene biomediese gebruike en daar was gevind dat dit vergelykbare akkuraatheid het. Die hartklanksiklusse van elke deelnemer is gesegmenteer deur EKG data en 'n eenvoudskromme te kombineer. Frekwensiegebiedskenmerke is uit elke hartsiklus onttrek en in 'n k-naastebuurpunt klassifiseerder ingevoer. Daar is tot die gevolgtrekking gekom dat die LDV deel van 'n outonome, kontaklose beluisteringstelsel kan uitmaak.
Livres sur le sujet "Cardiovascular system – ultrasonography"
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Abdul-Majeed, Salmasi, et Nicolaides Andrew N, dir. Cardiovascular applications of Doppler ultrasound. Edinburgh : Churchill Livingstone, 1989.
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1962-, Saijo Y., et Steen, A. F. W. van der 1964-, dir. Vascular ultrasound. Tokyo : Springer, 2003.
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Mayer, William V. Work of the heart. 2e éd. Chicago, Ill : Encyclopaedia Britannica Educational Corp., 1988.
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S, Abela George, Katzir Abraham, Society of Photo-optical Instrumentation Engineers. et Conference on Diagnostic and Therapeutic Cardiovascular Interventions (1992 : Los Angeles, Calif.), dir. Proceedings of diagnostic and therapeutic cardiovascular intervention II : 19-20 January 1992, Los Angeles, California. Bellingham, WA : SPIE (The Society of Photo-optical Instrumentation Engineers), 1992.
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S, Sideman, Beyar Rafael, Ṭekhniyon Makhon ṭekhnologi le-Yiśraʼel et International Henry Goldberg Workshop (1984 : Haifa, Israel), dir. Simulation and imaging of the cardiac system : State of the heart. Boston : M. Nijhoff Publishers, 1985.
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S, Abela George, Katzir Abraham et Society of Photo-optical Instrumentation Engineers., dir. Proceedings of diagnostic and therapeutic cardiovascular interventions IV : 22-23 January 1994, Los Angeles, California. Bellingham, Wash., USA : SPIE, 1994.
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M, Otto Catherine, dir. The practice of clinical echocardiography. Philadelphia : W.B. Saunders, 1997.
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M, Otto Catherine, dir. The practice of clinical echocardiography. 3e éd. Philadelphia, PA : Saunders/Elsevier, 2007.
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M, Otto Catherine, dir. The practice of clinical echocardiography. 3e éd. Philadelphia, PA : Saunders/Elsevier, 2007.
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M, Otto Catherine, dir. The practice of clinical echocardiography. 2e éd. Philadelphia : W.B. Saunders, 2002.
Trouver le texte intégralChapitres de livres sur le sujet "Cardiovascular system – ultrasonography"
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Tartaglia, Marco, et Bruce D. Gelb. « RAS Signaling Defects and Noonan Syndrome ». Dans Inborn Errors Of Development, 620–31. Oxford University PressNew York, NY, 2008. http://dx.doi.org/10.1093/oso/9780195306910.003.0063.
Texte intégralRésumé :
Abstract Moonan syndrome (OMIM 163950) is a pleomorphic disorder affecting the cardiovascular, craniofacial, skeletal, hematopoietic, lymphatic, and central nervous systems. It can result from mutations in the PTPN11 gene, which encodes the protein tyrosine phosphatase (PTP), Src homology 2 (SHP-2), or the KRAS gene, which encodes a RAS GTPase. The disorder is generally transmitted as an autosomal dominant trait, although many cases result from de novo mutations. Defects in the PTPN11 gene, which resides at chromosomal band 12q24.1, account for approximately 50% of cases. The more than 60 mutations that have been reported are mostly missense changes, with the vast majority affecting residues clustering at the interface between the N-terminal SH2 and PTP domains. Mutant SHP-2 proteins have a gain of function, usually through effects on the molecular switching mechanism important for activating/inactivating this enzyme. Missense PTPN11 mutations also recur in LEOPARD syndrome (MIM 151100), which is clinically related to Noonan syndrome. These mutations cause loss of catalytic activity of the phosphatase and are hypothesized to have dominant-negative effect on the wild-type protein. Defects in the KRAS gene account for approximately 2% of Noonan syndrome cases and engender gain of function in RAS signaling through reduced KRAS GTPase activity or increased GDP/GTP dissociation rate. Clinical manifestations of Noonan syndrome include a typical dysmorphic appearance, congenital heart defects [particularly pulmonic stenosis (PS)] or hypertrophic cardiomyopathy (HCM), webbing of the neck, short stature, cryptorchidism, eye abnormalities, and skeletal anomalies such as pectus deformities, cubitus valgus, and vertebral anomalies. A minority of affected individuals has bleeding diathesis, hearing loss, and mental retardation. Diagnosis is made by clinical examination. Prenatal diagnosis of Noonan syndrome may be suspected in the presence of ultrasonographic findings such as nuchal edema or cystic hygroma. Therapy in the neonatal period and infancy involves discovering and treating the cardiac disease and managing the feeding problems. Orchidopexy is indicated for undescended testes. Growth hormone (GH) therapy has been used to ameliorate the short stature. Preventive pediatric care is appropriate for the hematologic and developmental issues.
Actes de conférences sur le sujet "Cardiovascular system – ultrasonography"
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Rose, William C., David Johnson, Justin Spaeth, Jonathan Edwards et Antony Beris. « Computational and Experimental Investigation of Arterial Hemodynamics ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67860.
Texte intégralRésumé :
Dynamic arterial blood pressure and blood flow are key determinants of normal or pathological functioning of the cardiovascular system. The measurement of these variables at multiple locations in the body is clinically and physiologically valuable, but difficult to achieve except with invasive methods which carry significant risk to the patient. We have developed and here present a computational model of systemic arterial hemodynamics. The model predicts dynamic pressures and flows throughout the systemic arterial vascular bed. The inputs to the model are pressure or flow measured at a single site, and a description of the architectural and mechanical properties of the blood and blood vessels. We have also measured dynamic pressure and flow noninvasively in healthy women and men. We use these measurements to test and refine the model. The arterial model includes over 24 million blood vessels. The dimensions and branching patterns of 45 large arteries are derived from population averages. Approximately half of these vessels terminate in self-similar branching networks of arteries which extend to capillary-sized vessels. Womersley’s linearization of the Navier-Stokes equations is used to describe the relationship between pressure and flow in each vessel. The inviscid wave velocity in each vessel is estimated based on the combined effects of Young’s modulus, vessel thickness and diameter, and the rheological properties of blood. The blood is modeled as a non-Newtonian fluid whose hematocrit and viscosity vary with vessel size. Wave reflections are computed at all junctions between vessels. The nonlinear pressure drop occurring at the bifurcation of each vessel into daughter vessels is estimated and taken into account when computing the pressures and flows throughout the network. Dynamic pressure is measured noninvasively by applanation tonometry. Dynamic blood velocity is measured with Doppler ultrasonography, and vessel diameter is measured using ultrasound. Custom software uses the electrocardiogram to average data from multiple beats to create ensemble average waveforms for pressure, velocity, and diameter. Data has been collected from the radial and carotid arteries. The experimentally measured pressure from one site is used as input to the model. The model predictions are compared to the other experimental measurements. Blood vessel mechanical properties are estimated by adjusting the model parameters to get good agreement between measured and predicted quantities. This capability can be used to understand effects of pathological changes in vascular properties on local pressure and flow behavior throughout the vasculature.