Bibliographies thématiques / Cardiac kinematics

Littérature scientifique sur le sujet « Cardiac kinematics »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Cardiac kinematics"

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Cutrì, Elena, Paola Bagnoli, Emanuela Marcelli, Federico Biondi, Laura Cercenelli, Maria Laura Costantino, Gianni Plicchi et Roberto Fumero. « A Mechanical Simulator of Cardiac Wall Kinematics ». ASAIO Journal 56, no 3 (mai 2010) : 164–71. http://dx.doi.org/10.1097/mat.0b013e3181d7db0c.

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Tsamis, Alkiviadis, Allen Cheng, Tom C. Nguyen, Frank Langer, D. Craig Miller et Ellen Kuhl. « Kinematics of cardiac growth : In vivo characterization of growth tensors and strains ». Journal of the Mechanical Behavior of Biomedical Materials 8 (avril 2012) : 165–77. http://dx.doi.org/10.1016/j.jmbbm.2011.12.006.

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Damen, Frederick W., David T. Newton, Guang Lin et Craig J. Goergen. « Machine Learning Driven Contouring of High-Frequency Four-Dimensional Cardiac Ultrasound Data ». Applied Sciences 11, no 4 (13 février 2021) : 1690. http://dx.doi.org/10.3390/app11041690.

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Automatic boundary detection of 4D ultrasound (4DUS) cardiac data is a promising yet challenging application at the intersection of machine learning and medicine. Using recently developed murine 4DUS cardiac imaging data, we demonstrate here a set of three machine learning models that predict left ventricular wall kinematics along both the endo- and epi-cardial boundaries. Each model is fundamentally built on three key features: (1) the projection of raw US data to a lower dimensional subspace, (2) a smoothing spline basis across time, and (3) a strategic parameterization of the left ventricular boundaries. Model 1 is constructed such that boundary predictions are based on individual short-axis images, regardless of their relative position in the ventricle. Model 2 simultaneously incorporates parallel short-axis image data into their predictions. Model 3 builds on the multi-slice approach of model 2, but assists predictions with a single ground-truth position at end-diastole. To assess the performance of each model, Monte Carlo cross validation was used to assess the performance of each model on unseen data. For predicting the radial distance of the endocardium, models 1, 2, and 3 yielded average R2 values of 0.41, 0.49, and 0.71, respectively. Monte Carlo simulations of the endocardial wall showed significantly closer predictions when using model 2 versus model 1 at a rate of 48.67%, and using model 3 versus model 2 at a rate of 83.50%. These finding suggest that a machine learning approach where multi-slice data are simultaneously used as input and predictions are aided by a single user input yields the most robust performance. Subsequently, we explore the how metrics of cardiac kinematics compare between ground-truth contours and predicted boundaries. We observed negligible deviations from ground-truth when using predicted boundaries alone, except in the case of early diastolic strain rate, providing confidence for the use of such machine learning models for rapid and reliable assessments of murine cardiac function. To our knowledge, this is the first application of machine learning to murine left ventricular 4DUS data. Future work will be needed to strengthen both model performance and applicability to different cardiac disease models.
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Fassina, Lorenzo, Giovanni Magenes, Roberto Gimmelli et Fabio Naro. « Modulation of the Cardiomyocyte Contraction inside a Hydrostatic Pressure Bioreactor:In VitroVerification of the Frank-Starling Law ». BioMed Research International 2015 (2015) : 1–7. http://dx.doi.org/10.1155/2015/542105.

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We have studied beating mouse cardiac syncytiain vitroin order to assess the inotropic, ergotropic, and chronotropic effects of both increasing and decreasing hydrostatic pressures. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of those pressure-loaded beating syncytia starting from the video registration of their contraction movement. By this analysis, we have verified the Frank-Starling law of the heart inin vitrobeating cardiac syncytia and we have obtained their geometrical-functional classification.
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Fassina, Lorenzo, Marisa Cornacchione, Manuela Pellegrini, Maria Evelina Mognaschi, Roberto Gimmelli, Andrea Maria Isidori, Andrea Lenzi, Giovanni Magenes et Fabio Naro. « Model of Murine Ventricular Cardiac Tissue for In Vitro Kinematic-Dynamic Studies of Electromagnetic and β-Adrenergic Stimulation ». Journal of Healthcare Engineering 2017 (2017) : 1–7. http://dx.doi.org/10.1155/2017/4204085.

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In a model of murine ventricular cardiac tissue in vitro, we have studied the inotropic effects of electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of beating cardiac syncytia starting from the video registration of their contraction movement. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic effect of isoproterenol and to elicit an antihypertrophic response.
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Rozzi, Giacomo, Francesco P. Lo Muzio, Camilla Sandrini, Stefano Rossi, Lorenzo Fassina, Giuseppe Faggian, Michele Miragoli et Giovanni Battista Luciani. « Real-time video kinematic evaluation of the in situ beating right ventricle after pulmonary valve replacement in patients with tetralogy of Fallot : a pilot study ». Interactive CardioVascular and Thoracic Surgery 29, no 4 (9 juin 2019) : 625–31. http://dx.doi.org/10.1093/icvts/ivz120.

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Abstract OBJECTIVES The timing for pulmonary valve replacement (PVR) after tetralogy of Fallot repair is controversial, due to limitations in estimating right ventricular dysfunction and recovery. Intraoperative imaging could add prognostic information, but transoesophageal echocardiography is unsuitable for exploring right heart function. Right ventricular function after PVR was investigated in real time using a novel video-based contactless kinematic evaluation technology (Vi.Ki.E.), which calculates cardiac fatigue and energy consumption. METHODS Six consecutive patients undergoing PVR at 13.8 ± 2.6 years (range 6.9–19.8) after the repair of tetralogy of Fallot were enrolled. Mean right ventricular end-diastolic and end-systolic volume at magnetic resonance imaging were 115.6 ± 16.2 ml/m2 and 61.5 ± 14.6 ml/m2, respectively. Vi.Ki.E. uses a fast-resolution camera placed 45 cm above the open chest, recording cardiac kinematics before and after PVR. An algorithm defines cardiac parameters, such as energy, fatigue, maximum contraction velocity and tissue displacement. RESULTS There were no perioperative complications, with patients discharged in satisfactory clinical conditions after 7 ± 2 days (range 5–9). Vi.Ki.E. parameters describing right ventricular dysfunction decreased significantly after surgery: energy consumption by 45% [271 125 ± 9422 (mm/s)2 vs 149 202 ± 11 980 (mm/s)2, P = 0.0001], cardiac fatigue by 12% (292 671 ± 29 369 mm/s2 vs 258 755 ± 42 750 mm/s2, P = 0.01), contraction velocity by 54% (3412 ± 749 mm/s vs 1579 ± 400 mm/s, P = 0.0007) and displacement by 23% (27 ± 4 mm vs 21 ± 4 mm, P = 0.01). Patients undergoing PVR at lower end-diastolic volumes, had greater functional recovery of Vi.Ki.E. parameters. CONCLUSIONS Intraoperative Vi.Ki.E shows immediate recovery of right ventricular mechanics after PVR with less cardiac fatigue and energy consumption, providing novel insights that may have a prognostic relevance for functional recovery.
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Dabiri, John O., et Morteza Gharib. « The role of optimal vortex formation in biological fluid transport ». Proceedings of the Royal Society B : Biological Sciences 272, no 1572 (21 juin 2005) : 1557–60. http://dx.doi.org/10.1098/rspb.2005.3109.

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Animal phyla that require macro-scale fluid transport for functioning have repeatedly and often independently converged on the use of jet flows. During flow initiation these jets form fluid vortex rings, which facilitate mass transfer by stationary pumps (e.g. cardiac chambers) and momentum transfer by mobile systems (e.g. jet-propelled swimmers). Previous research has shown that vortex rings generated in the laboratory can be optimized for efficiency or thrust, based on the jet length-to-diameter ratio ( L / D ), with peak performance occurring at 3.5< L / D <4.5. Attempts to determine if biological jets achieve this optimization have been inconclusive, due to the inability to properly account for the diversity of jet kinematics found across animal phyla. We combine laboratory experiments, in situ observations and a framework that reduces the kinematics to a single parameter in order to quantitatively show that individual animal kinematics can be tuned in correlation with optimal vortex ring formation. This new approach identifies simple rules for effective fluid transport, facilitates comparative biological studies of jet flows across animal phyla irrespective of their specific functions and can be extended to unify theories of optimal jet-based and flapping-based vortex ring formation.
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Douglas, A. S., E. K. Rodriguez, W. O'Dell et W. C. Hunter. « Unique strain history during ejection in canine left ventricle ». American Journal of Physiology-Heart and Circulatory Physiology 260, no 5 (1 mai 1991) : H1596—H1611. http://dx.doi.org/10.1152/ajpheart.1991.260.5.h1596.

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Understanding the relationship between structure and function in the heart requires a knowledge of the connection between the local behavior of the myocardium (e.g., shortening) and the pumping action of the left ventricle. We asked the question, how do changes in preload and afterload affect the relationship between local myocardial deformation and ventricular volume? To study this, a set of small radiopaque beads was implanted in approximately 1 cm3 of the isolated canine heart left ventricular free wall. Using biplane cineradiography, we tracked the motion of these markers through various cardiac cycles (controlling pre- and afterload) using the relative motion of six markers to quantify the local three dimensional Lagrangian strain. Two different reference states (used to define the strains) were considered. First, we used the configuration of the heart at end diastole for that particular cardiac cycle to define the individual strains (which gave the local “shortening fraction”) and the ejection fraction. Second, we used a single reference state for all cardiac cycles i.e., the end-diastolic state at maximum volume, to define absolute strains (which gave local fractional length) and the volume fraction. The individual strain versus ejection fraction trajectories were dependent on preload and afterload. For any one heart, however, each component of absolute strain was more tightly correlated to volume fraction. Around each linear regression, the individual measurements of absolute strain scattered with standard errors that averaged less than 7% of their range. Thus the canine hearts examined had a preferred kinematic (shape) history during ejection, different from the kinematics of filling and independent or pre-or afterload and of stroke volume.
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Kindberg, K., M. Karlsson, N. B. Ingels et J. C. Criscione. « Nonhomogeneous Strain From Sparse Marker Arrays for Analysis of Transmural Myocardial Mechanics ». Journal of Biomechanical Engineering 129, no 4 (24 novembre 2006) : 603–10. http://dx.doi.org/10.1115/1.2746385.

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Background: Knowledge of normal cardiac kinematics is important when attempting to understand the mechanisms that impair the contractile function of the heart during disease. The complex kinematics of the heart can be studied by inserting radiopaque markers in the cardiac wall and study the pumping heart with biplane cineradiography. In order to study the local strain, the bead array was developed where small radiopaque beads are inserted along three columns transmurally in the left ventricle. Method: This paper suggests a straightforward method for strain computation, based on polynomial least-squares fitting and tailored for combined marker and bead array analyses. Results: This polynomial method gives small errors for a realistic bead array on an analytical test case. The method delivers an explicit expression of the Lagrangian strain tensor as a polynomial function of the coordinates of material points in the reference configuration. The method suggested in this paper is validated with analytical strains on a deforming cylinder resembling the heart, compared to a previously suggested finite element method, and applied to in vivo ovine data. The errors in the estimated strain components are shown to remain unchanged on an analytical test case when evaluating the effects of one missing bead. In conclusion, the proposed strain computation method is accurate and robust, with errors smaller or comparable to the current gold standard when applied on an analytical test case.
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Loschak, Paul M., Alperen Degirmenci, Cory M. Tschabrunn, Elad Anter et Robert D. Howe. « Automatically steering cardiac catheters in vivo with respiratory motion compensation ». International Journal of Robotics Research 39, no 5 (19 février 2020) : 586–97. http://dx.doi.org/10.1177/0278364920903785.

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A robotic system for automatically navigating ultrasound (US) imaging catheters can provide real-time intra-cardiac imaging for diagnosis and treatment while reducing the need for clinicians to perform manual catheter steering. Clinical deployment of such a system requires accurate navigation despite the presence of disturbances including cyclical physiological motions (e.g., respiration). In this work, we report results from in vivo trials of automatic target tracking using our system, which is the first to navigate cardiac catheters with respiratory motion compensation. The effects of respiratory disturbances on the US catheter are modeled and then applied to four-degree-of-freedom steering kinematics with predictive filtering. This enables the system to accurately steer the US catheter and aim the US imager at a target despite respiratory motion disturbance. In vivo animal respiratory motion compensation results demonstrate automatic US catheter steering to image a target ablation catheter with 1.05 mm and 1.33° mean absolute error. Robotic US catheter steering with motion compensation can improve cardiac catheterization techniques while reducing clinician effort and X-ray exposure.
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Thèses sur le sujet "Cardiac kinematics"

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Kindberg, Katarina. « Invasive and Non-Invasive Quantification of Cardiac Kinematics ». Doctoral thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-60202.

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The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. Myocardial motion can be measured by means of several different types of data acquisition. The earliest myocardial motion tracking technique was invasive, based on implanting radiopaque markers into the myocardium around the left ventricle, and recording the marker positions during the cardiac cycle by biplane cineradiography. Until recently, this was the only method with high enough spatial resolution of three-dimensional (3D) myocardial displacements to resolve transmural behaviors. However, the recent development of magnetic resonance imaging techniques, such as displacement encoding with stimulated echoes (DENSE), make detailed non-invasive 3D transmural kinematic analyses of human myocardium possible in the clinic and for research purposes. Diastolic left ventricular filling is a highly dynamic process with early and late transmitral inflows and it is determined by a complex sequence of many interrelated events and parameters. Extensive research has been performed to describe myocardial kinematics during the systolic phase of the cardiac cycle, but not by far the same amount of research has been accomplished during diastole. Measures of global and regional left ventricular kinematics during diastole are important when attempting to understand left ventricular filling characteristics in health and disease. This thesis presents methods for invasive and non-invasive quantification of cardiac kinematics, with focus on diastole. The project started by quantification of changes in global left ventricular kinematics during diastolic filling. The helical myocardial fiber architecture of the left ventricle produces both long- and short-axis motion as well as torsional deformation. The longitudinal excursion of the mitral annular plane is an important component of left ventricular filling and ejection. This was studied by analyzing the contribution of mitral annular dynamics to left ventricular filling volume in the ovine heart. In order to quantify strains for a specific body undergoing deformation, displacements for a set of internal points at a deformed configuration relative to a reference configuration are needed. A new method for strain quantification from measured myocardial displacements is presented in this thesis. The method is accurate and robust and delivers analytical expressions of the strain components. The developed strain quantification method is simple in nature which aids to bridge a possible gap in understanding between different disciplines and is well suited for sparse arrays of displacement data. Analyses of myocardial kinematics at the level of myocardial fibers require knowledge of cardiac tissue architecture. Temporal changes in myofiber directions during the cardiac cycle have been analyzed in the ovine heart by combining histological measurements of transmural myocardial architecture and local transmural strains. Rapid early diastolic filling is an essential component of the left ventricular function. Such filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. Failure of this process can lead to exercise intolerance and ultimately to heart failure. A thorough analysis of the relation between global left ventricular kinematics and local myocardial strain at the level of myocardial fibers during early diastole in the ovine heart was performed by applying the method for strain quantification and the technique for computing temporal changes in myocardial architecture on measures of myocardial displacements and tissue architecture in the ovine heart. As data acquisition technologies develop, quantification methods for cardiac kinematics need to be adapted and validated on the new types of data. Recent improvements of DENSE magnetic resonance imaging enable non-invasive transmural strain analyses in the human heart. The strain quantification method was first tailored to displacement data from a surgically implanted bead array but has been extended to applications on non-invasive DENSE data measured in two and three dimensions. Validation against an analytical standard reveals accurate results and in vivo strains agree with values for normal human hearts from other studies. The method has in this thesis been used with displacement data from invasive marker technology and non-invasive DENSE magnetic resonance imaging, but can equally well be applied on any type of displacement data provided that the spatial resolution is high enough to resolve local strain variations.
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Prakosa, Adityo. « Analysis and simulation of multimodal cardiac images to study the heart function ». Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00837857.

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This thesis focuses on the analysis of the cardiac electrical and kinematic function for heart failure patients. An expected outcome is a set of computational tools that may help a clinician in understanding, diagnosing and treating patients suffering from cardiac motion asynchrony, a specific aspect of heart failure. Understanding the inverse electro-kinematic coupling relationship is the main task of this study. With this knowledge, the widely available cardiac image sequences acquired non-invasively at clinics could be used to estimate the cardiac electrophysiology (EP) without having to perform the invasive cardiac EP mapping procedures. To this end, we use real clinical cardiac sequence and a cardiac electromechanical model to create controlled synthetic sequence so as to produce a training set in an attempt to learn the cardiac electro-kinematic relationship. Creating patient-specific database of synthetic sequences allows us to study this relationship using a machine learning approach. A first contribution of this work is a non-linear registration method applied and evaluated on cardiac sequences to estimate the cardiac motion. Second, a new approach in the generation of the synthetic but virtually realistic cardiac sequence which combines a biophysical model and clinical images is developed. Finally, we present the cardiac electrophysiological activation time estimation from medical images using a patient-specific database of synthetic image sequences.
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Rozzi, Giacomo. « VIDEO KINEMATIC EVALUATION OF THE HEART (VI.KI.E.) : AN IDEA, A PROJECT, A REALITY ». Doctoral thesis, 2020. http://hdl.handle.net/11562/1017185.

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Introduction: The technological development of the last 20 years pledges the intensity of efforts for implementing novel imaging contactless modalities that accelerate the translation from the research bench to the patient bedside, especially in the cardiac field. In this work, a novel intraoperative cardiac imaging approach, named Video Kinematic Evaluation (Vi.Ki.E.), is presented and explained in detail. This technology is able to monitor, contactless, the cardiac mechanics and deformation in-situ during heart surgery. Cardiac kinematics have been deeply evaluated ranging from the experimental animal approach to the human myocardial pathologies in both left and right ventricles. Methods: Vi.Ki.E. can be defined “as simple as innovative”. It only consists of a high-speed camera placed upon an exposed beating heart in-situ to record cardiac cycles. Afterwards a tracker software is used on the recorded video to follow the epicardial tissue movements. This tracker provides information about trajectories of the epicardium and, thanks to a custom-made algorithm, the technology supplies heart mechanical information such as: Force of contraction or cardiac fatigue, Energy expenditure, Contraction velocity, displacement of the marker and epicardial torsion. This approach has been tested on 21 rats (9 ischemia/reperfusion and/or for validation, 12 for the gender difference study) and on 37 patients who underwent different surgery between 2015 and 2019. In detail 10 patients underwent Coronary Artery Bypass Grafting, 12 underwent Valve Replacement after Tetralogy of Fallot correction surgery, 6 implanted a Left Ventricular Assist Device (1 is moved in the case study section), 6 patients with Hypoplastic Heart Syndrome underwent GLENN or FONTAN surgery, 2 patients underwent Heart Transplantation and finally 1 patient underwent double valve replacement (this patient is moved into case study section). Results: The patients’ results demonstrated that the Vi.Ki.E. technology was able to discriminate, with statistic potency, the kinematic differences before and after the surgery in real-time, suggesting possible clinical implications in the treatment of the patients before the chest closure and/or in the intensive care unit. As it concerns the experimental animals, the results are the basics of the validation technology. Some of them were used as accepted model in comparison with the Vi.Ki.E. results on patients. Conclusions: In conclusion, this study has shown that Vi.Ki.E. is a safe and contactless technology with promising possible clinical application. The ease in the evaluation and the algorithm-based approach makes Video Kinematic Evaluation a widespread technique from cellular level to human cases covering the entire experimental field with in-vivo evaluation and possibly Langendorff/Working Heart approaches.
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Muzio, Francesco Paolo Lo. « Video Kinematic Evaluation : new insights on the cardiac mechanical function ». Doctoral thesis, 2022. http://hdl.handle.net/11562/1069146.

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The cardiac mechanical function plays a critical role in governing and regulating its performance under both normal and pathological conditions. The left ventricle has historically received more attention in both congenital and acquired heart diseases and was considered as the mainstay of normal hemodynamics. However, over the past few decades, there has been increasing recognition of the pivotal role of the right ventricle in determining functional performance status and prognosis in multiple conditions. Nonetheless, the ventricles should not be considered separately as they share the septum, are encircled with common myocardial fibers and are surrounded by the pericardium. Thus, changes in the filling of one ventricle may alter the mechanical function of its counterpart. This ventricular interdependence remains even after the removal of the pericardium because of constrictive pericarditis or during open chest surgery. Interestingly, during open chest surgery, only the right ventricle mechanical activity is visually checked by the surgeon and cardiologist due to the absence of an intraoperative imaging technique able to evaluate its complex function. Noteworthy, most of the imaging techniques available to clinicians are established for the assessment of the left ventricle, with the ejection fraction being the most used parameter. However, this value is a measure of global systolic function which comes short in identifying regional myocardial impairment and the mechanical contraction. Therefore, new approaches are needed to deeply investigate the mechanics of both ventricles and correctly assess the cardiac mechanical performance. In this thesis, I studied the mechanical function of the left ventricle through different modalities of cardiac magnetic resonance and employed an innovative imaging technique for the assessment of the right ventricle mechanical function during open chest surgery.
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Michaud, Benjamin. « Complexe d'épaule dans un contexte d'analyse tridimentionnel - Modélisation et mise en garde ». Thèse, 2012. http://hdl.handle.net/1866/8880.

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L'épaule est un complexe articulaire formé par le thorax, la clavicule, la scapula et l'humérus. Alors que les orientation et position de ces derniers la rendent difficile à étudier, la compréhension approfondie de l'interrelation de ces segments demeure cliniquement importante. Ainsi, un nouveau modèle du membre supérieur est développé et présenté. La cinématique articulaire de 15 sujets sains est collectée et reconstruite à l'aide du modèle. Celle-ci s'avère être généralement moins variable et plus facilement interprétable que le modèle de référence. Parallèlement, l'utilisation de simplifications, issues de la 2D, sur le calcul d'amplitude de mouvement en 3D est critiquée. Cependant, des cas d'exception où ces simplifications s'appliquent sont dégagés et prouvés. Ainsi, ils sont une éventuelle avenue d'amélioration supplémentaire des modèles sans compromission de leur validé.
The shoulder is an articulated complex composed of the thorax, clavicle, scapula and humerus. While the relative orientation and position of the segments makes an in-depth study of the shoulder difficult, understanding the interaction between the segments remains clinically important. Thus, a new model of the upper limb is proposed. Joint kinematics of 15 subjects were collected and reconstructed using the model, and were found to be less variable and easier to interpret when compared to the reference model. Meanwhile, simplifications involving the use of 2D analysis to calculate range of motion in 3D are criticized. Exceptions where these simplifications apply, were however, shown. Thus, such simplifications can be applied to models in certain situations without compromising the models validity.
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Ільків, Василь Миколайович, et Vasyl Ilkiv. « Обґрунтування параметрів приводу грейферного навантажувача ». Master's thesis, 2020. http://elartu.tntu.edu.ua/handle/lib/33462.

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В дипломній роботі запропоновано конструктивні рішення з удосконалення конструкції приводу грейферного навантажувача, що забезпечує зменшення затрат на його ремонт та технічне обслуговування.
In the work is a proposed constructive solution for the improvement of the drive grab loader that reduces the cost of its repair and maintenance.
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Chapitres de livres sur le sujet "Cardiac kinematics"

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Wong, Ken C. L., Heye Zhang, Huafeng Liu et Pengcheng Shi. « Physiome Model Based State-Space Framework for Cardiac Kinematics Recovery ». Dans Medical Image Computing and Computer-Assisted Intervention – MICCAI 2006, 720–27. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11866565_88.

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Shi, Pengcheng, et Huafeng Liu. « Stochastic Finite Element Framework for Cardiac Kinematics Function and Material Property Analysis ». Dans Medical Image Computing and Computer-Assisted Intervention — MICCAI 2002, 634–41. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45786-0_78.

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Perotti, Luigi E., Patrick Magrath, Ilya A. Verzhbinsky, Eric Aliotta, Kévin Moulin et Daniel B. Ennis. « Microstructurally Anchored Cardiac Kinematics by Combining In Vivo DENSE MRI and cDTI ». Dans Functional Imaging and Modelling of the Heart, 381–91. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59448-4_36.

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Keler, M. « Geometry of Homokinematic Spatial Cardan Shafts by Dual Methods ». Dans Advances in Robot Kinematics, 43–52. Dordrecht : Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4120-8_5.

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Jahn, Philipp, Jakob Hentschel et Annika Raatz. « Design and Analysis of a Compliant Parallel Robot with Cardan Joints for a Cryogenic Working Environment ». Dans Advances in Robot Kinematics 2022, 220–27. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08140-8_24.

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Prakosa, Adityo, Maxime Sermesant, Hervé Delingette, Eric Saloux, Pascal Allain, Pascal Cathier, Patrick Etyngier, Nicolas Villain et Nicholas Ayache. « Synthetic Echocardiographic Image Sequences for Cardiac Inverse Electro-Kinematic Learning ». Dans Lecture Notes in Computer Science, 500–507. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23623-5_63.

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Griffa, Petro, Alessandro Filippeschi et Carlo Alberto Avizzano. « Kinematic Optimization for the Design of a UR5 Robot End-Effector for Cardiac Tele-Ultrasonography ». Dans Mechanisms and Machine Science, 423–30. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-55807-9_48.

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Kovács, Sándor J. « The heart as a pump : governing principles ». Dans ESC CardioMed, sous la direction de Guido Grassi, 111–15. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0021.

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The pumping attributes of the heart remain active topics of investigation and mastery of how the heart functions as a pump is part of the fund of knowledge of physiologists and cardiologists. The advent of high-resolution, real-time imaging (computed tomography, magnetic resonance imaging cardiac catheterization, two- and three-dimensional echocardiography) has continued to advance our understanding of how the four-chambered heart (left heart, right heart) works as it fills and as it empties. The insights that have evolved emanate from a conceptual framework based on motion (kinematics) of selected phases and portions of the four-chambered heart and the contents of the pericardial sac. Concepts include pressure pumping, volume pumping, constant-volume pumping, the relationship between atrial and ventricular function and atrial and ventricular indexes, the role of the heart as a suction pump, laws that govern isovolumic relaxation, and the relationship of intraventricular fluid mechanics to diastolic function and wall motion. Accordingly, by asking such questions as ‘What is the ejection fraction of the pericardial sack, and why does it have the numerical value it has?’ or ‘Why does the left atrium fill in two phases—one in systole and one in diastole?’ or ‘How is atrial conduit volume related to diastolic wall motion?’ one can gain new insights into pumping function. This chapter presents a simple, useful, yet powerful conceptual framework that can be used descriptively or mathematically to addresses these and other clinically important themes.
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Kovács, Sándor J. « The heart as a pump : governing principles ». Dans ESC CardioMed, sous la direction de Guido Grassi, 111–15. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0021_update_001.

Texte intégral
Résumé :
The pumping attributes of the heart remain active topics of investigation and mastery of how the heart functions as a pump is part of the fund of knowledge of physiologists and cardiologists. The advent of high-resolution, real-time imaging (computed tomography, magnetic resonance imaging cardiac catheterization, two- and three-dimensional echocardiography) has continued to advance our understanding of how the four-chambered heart (left heart, right heart) works as it fills and as it empties. The insights that have evolved emanate from a conceptual framework based on motion (kinematics) of selected phases and portions of the four-chambered heart and the contents of the pericardial sac. Concepts include pressure pumping, volume pumping, constant-volume pumping, the relationship between atrial and ventricular function and atrial and ventricular indexes, the role of the heart as a suction pump, laws that govern isovolumic relaxation, and the relationship of intraventricular fluid mechanics to diastolic function and wall motion. Accordingly, by asking such questions as ‘What is the ejection fraction of the pericardial sack, and why does it have the numerical value it has?’ or ‘Why does the left atrium fill in two phases—one in systole and one in diastole?’ or ‘How is atrial conduit volume related to diastolic wall motion?’ one can gain new insights into pumping function. This chapter presents a simple, useful, yet powerful conceptual framework that can be used descriptively or mathematically to addresses these and other clinically important themes.
Styles APA, Harvard, Vancouver, ISO, etc.
10

Kovács, Sándor J. « The heart as a pump : governing principles ». Dans ESC CardioMed, sous la direction de Guido Grassi, 111–15. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0021_update_002.

Texte intégral
Résumé :
The pumping attributes of the heart remain active topics of investigation and mastery of how the heart functions as a pump is part of the fund of knowledge of physiologists and cardiologists. The advent of high-resolution, real-time imaging (computed tomography, magnetic resonance imaging cardiac catheterization, two- and three-dimensional echocardiography) has continued to advance our understanding of how the four-chambered heart (left heart, right heart) works as it fills and as it empties. The insights that have evolved emanate from a conceptual framework based on motion (kinematics) of selected phases and portions of the four-chambered heart and the contents of the pericardial sac. Concepts include pressure pumping, volume pumping, constant-volume pumping, the relationship between atrial and ventricular function and atrial and ventricular indexes, the role of the heart as a suction pump, laws that govern isovolumic relaxation, and the relationship of intraventricular fluid mechanics to diastolic function and wall motion. Accordingly, by asking such questions as ‘What is the ejection fraction of the pericardial sack, and why does it have the numerical value it has?’ or ‘Why does the left atrium fill in two phases—one in systole and one in diastole?’ or ‘How is atrial conduit volume related to diastolic wall motion?’ one can gain new insights into pumping function. This chapter presents a simple, useful, yet powerful conceptual framework that can be used descriptively or mathematically to addresses these and other clinically important themes.
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Actes de conférences sur le sujet "Cardiac kinematics"

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Ganji, Yusof, et Farrokh Janabi-Sharifi. « Catheter kinematics and control to enhance cardiac ablation ». Dans Optics East 2006, sous la direction de Yukitoshi Otani et Farrokh Janabi-Sharifi. SPIE, 2006. http://dx.doi.org/10.1117/12.686434.

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LIU, HUAFENG, et PENGCHENG SHI. « BIOMECHANICALLY CONSTRAINED MULTIFRAME ESTIMATION OF NONRIGID CARDIAC KINEMATICS FROM MEDICAL IMAGE SEQUENCE ». Dans Proceedings of the International Conference on Inverse Problems. WORLD SCIENTIFIC, 2003. http://dx.doi.org/10.1142/9789812704924_0035.

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Shan Tong, A. Sinusas et Pengcheng Shi. « Continuous-Discrete Filtering for Cardiac Kinematics Estimation under Spatio-Temporal Biomechanical Constrains ». Dans 18th International Conference on Pattern Recognition (ICPR'06). IEEE, 2006. http://dx.doi.org/10.1109/icpr.2006.413.

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Marcelli, E., S. Spolzino, L. Cercenelli, A. Cappello, P. Bagnoli, M. L. Costantino, N. Malagutti, R. Fumero et G. Plicchi. « Assessment of cardiac apex kinematics using a real-time 3D magnetic tracking system ». Dans 2008 35th Annual Computers in Cardiology Conference. IEEE, 2008. http://dx.doi.org/10.1109/cic.2008.4749062.

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Tong, Shan, Albert Sinusas et Pengcheng Shi. « Sampled-Data ηα Filtering for Robust Kinematics Estimation : Applications to Biomechanics-Based Cardiac Image Analysis ». Dans 2006 International Conference on Image Processing. IEEE, 2006. http://dx.doi.org/10.1109/icip.2006.312955.

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Moreno, Michael, Saurabh Biswas, Lewis D. Harrison, Guillaume Pernelle, Matthew W. Miller, Theresa W. Fossum, David A. Nelson et John C. Criscione. « Assessment of Minimally Invasive Device That Provides Simultaneous Adjustable Cardiac Support and Active Synchronous Assist in an Acute Heart Failure Model ». Dans ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53089.

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Congestive heart failure (CHF) is a debilitating disease that is generally initiated by some index cardiac event and ultimately characterized by left ventricular (LV) remodeling which dramatically alters the mechanical environment about the heart. It is well established that mechanical stimuli (e.g., stress or strain) are important epigenetic factors in cardiovascular development, adaptation, and disease.1–3 Interestingly, abnormal cardiac kinematics is often considered a symptom of heart failure when in actuality it is likely a primary contributing factor to the relentless progression of the disease.4 Cellular responses to pathologic mechanical factors lead to further pathologic remodeling and a positive feedback loop emerges such that eventually a threshold is reached wherein the neurohormal compensatory mechanisms activated to maintain homeostasis following the initial cardiac event are no longer sufficient to deter further progression of the disease. Consequently, treatment strategies that fail to remedy the aberrant mechanical environment become increasingly ineffective as the disease progresses.
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Schinstock, Emma, Xiaoyin Ling, Renato Conedera, Aaron Tucker et David Ramirez. « Constant Force Application on a Beating Swine Heart : Robotic Assistance for Mapping and Ablation Procedures ». Dans 2019 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/dmd2019-3253.

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Robot assisted surgery has been widely accepted by the medical community. Surgeons utilize robots in many different procedures worldwide. However, cardiothoracic surgeons do not regularly use robotic tools to aid them in performing even simple, catheter based procedures such as cardiac ablation or mapping. Some cardiac Monophasic Action Potentials (MAPs) and ablation catheters require a specific window of force to either effectively characterize or scar cardiac tissue. This is challenging to maintain through the cardiac cycle, so the application of a constant force is not a trivial task for surgeons. Robotic assistance to control the force applied to a catheter through ablation and mapping procedures is needed to improve the outcome for patients. The purpose of this work is to develop a single degree of freedom robot that controls the force applied to a beating swine heart. Rather than trying to predict the motion and timing of the heartbeat, or tracking its movement this robot senses and reacts to the force produced by the myocardium. Through the cardiac cycle, the robot applies a constant force to the surface of a beating heart. The kinematics of the cardiac tissue were characterized by utilizing piezoelectric transducers. Hardware to control the catheter motion was designed to fit most commercially available devices. The controller was designed by first building a mathematical model using measured data, and then a control law was implemented considering the heartbeat as disturbances to the system. Finally, testing was completed with dry runs, and in situ and ex-vivo testing in the Visible Heart® Laboratory.
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Borazjani, Iman, Liang Ge, Fotis Sotiropoulos, Lakshmi Prasad Dasi et Ajit Yogonathan. « Fluid-Structure Interaction in Bi-Leaflet Mechanical Heart Valves ». Dans ASME 2007 2nd Frontiers in Biomedical Devices Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/biomed2007-38074.

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In this work we focus on the fluid-structure interaction (FSI) problem of a St. Jude Regent 23mm bi-leaflet mechanical heart valve (BMHV) implanted in modeled straight aorta geometry with a simplified sinus. A FSI solver based on a recently developed curvilinear grid/immersed boundary method fluid flow solver is developed. The current numerical simulation focuses on the acceleration phase within the cardiac cycle when the leaflets are opening following the incoming flow. The simulated results are compared with experimental data with regard to the leaflet kinematics as well as valve induced wake vortical structures and excellent agreement between the simulation and measurements is reported.
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Fassina, Lorenzo, Antonio Di Grazia, Fabio Naro, Salvatore Aguanno, Marisa Cornacchione, Maria Gabriella Cusella De Angelis, Francesca Sardi et Giovanni Magenes. « Effects of the hydrostatic pressure in in vitro beating cardiac syncytia in terms of kinematics (kinetic energy and beat frequency) and syncytia geometrical-functional classification ». Dans 2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2013. http://dx.doi.org/10.1109/embc.2013.6609635.

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Nelson, Carl A., et Judith M. Burnfield. « Improved Elliptical Trainer Biomechanics Using a Modified Cardan Gear ». Dans ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70439.

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Although many different kinematic structures have been employed in the design of elliptical machines for exercise and fitness, these devices in general do not produce pedal paths that promote lower extremity kinematics similar to overground gait. This is unfortunate given the growing interest in using these devices as a gait rehabilitation tool. In this paper, we present a novel design strategy for elliptical machines intended to create a movement profile that more closely simulates the lower extremity kinematics of gait. This involves replacement of the typical crank link with a modified Cardan gear system. Simulations of typical rear-drive (crank-rocker) and front-drive (crank-slider) elliptical designs validate the improvement in lower limb hip and knee kinematics using this approach, suggesting that assistive elliptical rehabilitation systems can be more optimally designed to promote normal lower extremity gait kinematics compared to currently available devices.
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