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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Estimativa do número de cardiomiócitos do ventrículo esquerdo em suínos (Sus scrofa) / Estimation of the cardyomyocites number in the left ventrcle in swine (Sus scrofa)

Carlos Alberto Palmeira Sarmento 26 June 2009 (has links)
Os estudos relacionados ao coração têm sido realizados ao longo dos anos de forma bastante comum, tendo em vista a grande importância que este órgão tem na medicina. Problemas relacionados ao mesmo são uma das principais causas de mortes e internações no Brasil e no mundo, por causa disso, avanços no que diz respeito a inovações tecnológicas e novas metodologias de estudo tem sido propostas cada vez com mais freqüência, e, o suíno tem se mostrado um modelo bastante útil, pois apresenta diversas similaridades em relação ao ser humano.O uso da estereologia se encaixa nesta nova busca, pois através de suas ferramentas nos proporciona excelentes resultados a níveis de mensuração, e quantificação de estruturas microscópicas. O objetivo desse estudo foi obter valores referentes à quantificação de cardiomiócitos do ventrículo esquerdo em suínos normais. Utilizaram-se 3 suínos fêmeas pesando em torno de 25kg, os quais após serem eutanasiados tiveram o coração retirado e suas câmaras separadas. Em seguida lâminas referentes a esse material foram preparadas e fotografadas, para serem analizadas utilizando-se o disector e o nucleator como ferramentas estereologicas. Os resultados nos mostram que a média de peso do ventrículo esquerdo dos animais foi de 660 mg, o volume médio dos cardiomiócitos foi de 16.32 µm³, a média do numero de cardiomiócitos foi de 3,91x108, enquanto que a média do volume de cardiomiócitos que ocupam o ventrículo esquerdo foi de 3,32x106. / Investigations involving the heart have been largely carried out all over the years due to its importance in medicine. Heart diseases are the one of the major causes of deaths and hospitalizations in Brazil and worldwide. In this context, technological innovations and progresses in methodological investigation have been frequently proposed; Swine has been shown as a useful model due to similarities to human. The application of stereological tools for investigations in the morphology of the heart has been intensely applied based on the reliability on the results for measuring and quantification. This study aimed to evaluate morphological and quantitative aspects of cardiomyocytes in the left ventricle in healthy swine. Three female swine, averaging 25 kg were euthanasiated and have the hearth chambers separated. Left ventricles were fixed and slides obtained. Images were acquired and analyzed by dissector and nucleator. The results showed us that the average weight of the left ventricle of the animals was 660 mg, the mean volume of cardiomyocytes was 16:32 µm3, the average number of cardiomyocytes was 3.91 x108, while the average volume of cardiomyocytes that occupy the left ventricle was 3.32 x106.
72

Estudo da anatomia endoscópica ventricular em cadáveres humanos brasileiros não fixados para realização de terceiro ventriculostomia / Study of ventricular endoscopic anatomy on Brazilian human cadavers non-fixed for the performance of the third ventriculostomy

Alicia Del Carmen Becerra Romero 27 August 2010 (has links)
INTRODUÇÃO: O objetivo desta pesquisa foi medir, através da endoscopia, o plexo corióideo no forame interventricular e estruturas no assoalho do terceiro ventrículo, bem como a distância entre as artérias comunicantes posteriores e comparar essas variáveis. MÉTODOS: Estudo observacional, prospectivo realizado em 37 cérebros de cadáveres humanos adultos, de ambos os sexos, no Serviço de Verificação de Óbitos da Universidade de São Paulo, em abril de 2008, utilizando neuroendoscópio rígido. As imagens endoscópicas foram gravadas, corrigidas para distorção e mensuradas. A medida macroscópica entre as artérias comunicantes posteriores foi realizada após o estudo endoscópico. RESULTADOS: As medidas do plexo corióideo no forame interventricular, a distância látero-lateral dos corpos mamilares, a distância do recesso do infundíbulo até os corpos mamilares e do triângulo de segurança no túber cinéreo foram 1,71 mm (±0,77 mm), 2,23 mm (±0,74 mm), 3,22 mm (±0,82 mm), 3,69 mm2 (±2,09 mm2), respectivamente. O aspecto do assoalho do terceiro ventrículo e a distância interna dos corpos mamilares foi 84% opaco e 89% ausente, respectivamente. A distância média entre as artérias comunicantes posteriores foi de 12,5 mm (±2,3 mm). Associações entre translucidez do assoalho do terceiro ventrículo com as seguintes variáveis: distância láterolateral e distância interna dos corpos mamilares, assim como idade, foram identificadas. CONCLUSÕES: Até esta pesquisa, não existiam medidas sobre o plexo corióideo no forame interventricular e distância entre as artérias comunicantes posteriores na região dos corpos mamilares. As variáveis restantes, quando comparadas com a literatura, foram em maior número e em cérebros normais / INTRODUCTION: the objective of this research was to measure, through endoscopy, the interventricular foramen choroid plexus and the third ventricle floor structures, as well the distance between the communicating posterior arteries and compare these variables. METHODS: an observational, prospective study was conducted in 37 brains of adult human cadavers, of both sexes at the Death Check Unit of the University of São Paulo, in April 2008 by means of the rigid neuroendoscope. The endoscopic images were recorded, corrected for distortion and measured. The macroscopic measure between the communicating posterior arteries was performed after the endoscopic study. RESULTS: The measures of the interventricular foramen choroid plexus, the latero-lateral distance of mammillary bodies, the distance from the infundibular recess to the mammillary bodies, safety triangle in the tuber cinereum were 1.71 mm (±0.77 mm), 2.23 mm (±0.74 mm), 3.22 mm (±0.82 mm), 3.69 mm2 (±2.09 mm2), respectively. The aspect of the third ventricle floor and the internal distance of the mammillary bodies was 84% opaque and 89% absent, respectively. The mean distance between the communicating posterior arteries was 12.5 mm (±2.3 mm). Associations between the translucent floor of the third ventricle with the following variables: latero-lateral distance and internal distance of the mammillary bodies, as well as age were identified. CONCLUSIONS: Up this research, there was no account on the measures of the interventricular foramen choroid plexus and the distance between communicating posterior arteries at the level of the mammillary bodies. The remaining variables were in greater number and in normal brains, as compared with the literature
73

Estudo morfoquantitativo do miocárdio do ventrículo esquerdo de ratas ooforectomizadas submetidas a exercício aeróbico / Morphoquantitative Study of Myocardium of Left Ventricle of Ooforectomized Rats Submitted to Aerobic Exercise

Amanda Messias Vazzoler 21 July 2008 (has links)
Diversos estudos indicam que a deficiência de estrógeno aumenta a incidência de doenças cardiovasculares em mulheres na pós-menopausa. Os efeitos decorrentes da deprivação de estrógeno no miocárdio ainda não estão totalmente esclarecidos. Estudos têm evidenciado efeitos benéficos da atividade física no sistema cardiovascular, em qualquer condição, em especial na menopausa. Utilizando ratos Wistar, como modelo experimental, os objetivos deste trabalho são: a) verificar se a ooforectomia e a atividade física produzem alterações no miocárdio do ventrículo esquerdo, b) verificar se a realização do exercício físico aeróbico tem efeito sobre essas alterações. Para a realização deste estudo foram utilizadas 15 ratas com 6 meses de idade, da linhagem Wistar, distribuídas em 3 grupos de 5 ratas cada: GC- Ratas com 6 meses de idade sem ooforectomia e sem atividade física; GS- Ratas com 6 meses de idade com ooforectomia bilateral sem atividade física; GA- Ratas com 6 meses de idade com ooforectomia bilateral que realizaram atividade física (corrida em esteira) durante 3 meses. Os animais dos 3 grupos foram eutanasiados com 9 meses de idade. A avaliação foi realizada através de microscopia de luz e estereologia. Os cortes histológicos foram corados por: Hematoxilina-Eosina e Picrosírius. Na parede do ventrículo esquerdo foram estimadas as densidades de volume dos cardiomiócitos, do tecido conjuntivo e a densidade de comprimento e densidade de volume dos vasos intramiocárdicos. Foi estimado o número total de núcleos de cardiomiócitos e sua densidade numérica foi estimada através do método disector. Os dados quantitativos dos três grupos foram estatisticamente comparados através do ANOVA e teste de Tukey. Os resultados mostraram que houve um aumento de peso nos animais do GS e GA em relação ao GC. Quanto ao treinamento, os animais do GA tiveram melhor rendimento nos TEMs. Quanto ao volume do VE, observamos uma diminuição, embora não significante, nos animais do GS e GA em relação ao GC. A densidade de volume dos vasos intramiocárdicos foi maior no GC que no GA. As diferenças não foram estatisticamente significantes em relação à ooforectomia e ao exercício físico para os parâmetros: densidade de volume dos cardiomiócitos e do tecido conjuntivo, densidade de comprimento dos vasos intramiocárdicos, densidade numérica dos núcleos dos cardiomiócitos, número total de núcleos de cardiomiócitos e densidade numérica do colágeno. Esses dados nos levam a concluir que a ooforectomia acarreta alterações no volume do ventrículo esquerdo e a atividade física diminui a densidade de volume dos vasos intramiocárdicos. Quanto aos outros itens, nem a ooforectomia, nem a atividade física, isoladamente ou associada, parecem influenciar de maneira significativa nestes dados. / Severals studies indicate that the estrogen deficiency increase the incidence of the cardiovascular diseases in women in the post-menopausal period. The effects of the estrogen deprivation in the myocardium still remain unclear. Studies have proved beneficial effects of the physical activity in the cardiovascular system, especially in the menopause. Using Wistar rats, as an experimental model, the aims of this work are: a-) to check if the ooforectomy and the physical activity produce alterations in the left ventricle of the myocardium; b-) to check if the aerobic exercise realization affects these alterations. To achieve these goals it was used 15 Wistar rats of 6 months of age, distributed in 3 groups of five rats each: Control group- Rats with six months of age without ooforectomy and physical activity; GS- Rats with six months of age with ofoorectomy bilateral and without physical activity and, GA- Rats with six months of age with ooforectomy bilateral and physical activity during 3 months. Al rats were euthanasied with 9 months of age. The results were obtained by using light microscopy were and stereology. The histological section was stained with Hematoxylin and Eosin, and Picrosirius stain. On the wall of the left ventricle were estimated the density of volume of the cardiomiocyt, of the connective tissue and the density of length and the density of volume of the intramyocardial vessels. It was estimated the total number of nuclei of cardiomiocyt and its numerical density was estimated a cross the disector method. The data of the three groups were statistically compared for the ANOVA and Tukey´s test. The results showed that there was an increase in the weight in the animals of GS and of GA. In relation to training, the animals of GA obtained the best income in the TEMs. In relation to the volume of the left ventricle, it was observed a decrease, although not significant, in the animals of GS and GA. The density of volume of the intramyocardial vessels was higher in the GC than GA. In relation to the ooforectomy and the physical exercise for the items: density of volume of the cardiomiocyt and of the connective tissue, density of length of the intramyocardial vessels, numerical density of nuclei of cardiomiocyt, total number of nuclei of cardiomiocyt and numerical density of collagen, the differences werent significant. We can conclude that the ooforectomy result in changes in the volume of the left ventricle and that the physical activity decrease the density of volume of the intramyocardial. In relation to the other items, neither the ooforectomy, neither the physical activity, alone or together, seem doesn\'t affect these data.
74

On the assessment of right ventricular function using cardiac magnetic resonance imaging and echocardiography

Jorstig, Stina January 2016 (has links)
Transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging are two commonly used imaging modalities for evaluating the size and function of the heart. There are advantages and disadvantages associated with both modalities when examining the right ventricle (RV). The RV is positioned partly behind the sternum and lung, sometimes causing shadows in the TTE images. This along with the complex shape of the RV makes volume calculations challenging by 2D TTE. CMR is considered to be the reference method for volume calculations of the ventricles. The valve separating the RV from the right atrium is however often oblique compared to the valve separating the left ventricle from the left atrium. This complicates RV volume calculations using conventional CMR short-axis stack images. The aim of this thesis was to find ways to improve the RV stroke volume and ejection fraction calculations using TTE and CMR. A method, transferring the position of the tricuspid plane from RV long-axis images to short-axis images, was developed to improve the separation of the right atrium from the RV when calculating RV stroke volumes by CMR. The method provided calculations of RV stroke volumes with good agreement to reference volumes. Further, the movements contributing to the RV stroke volume was studied aiming to find new ways of calculating RV stroke volumes and ejection fraction by TTE. A model for RV stroke volume and ejection fraction calculations was evaluated showing underestimation of stroke volumes by TTE compared to CMR, which probably depend on differences in distance measurements using the two modalities. The model provided, however, promising results for ejection fraction calculations which was validated in a study of 37 participants that covered a wide range of EF.
75

Simulation of Myocardium Motion and Blood Flow in the Heart with Fluid-Structure Interaction

Doyle, Matthew Gerard January 2011 (has links)
The heart is a complex organ and much is still unknown about its mechanical function. In order to use simulations to study heart mechanics, fluid and solid components and their interaction should be incorporated into any numerical model. Many previous studies have focused on myocardium motion or blood flow separately, while neglecting their interaction. Previous fluid-structure interaction (FSI) simulations of heart mechanics have made simplifying assumptions about their solid models, which prevented them from accurately predicting the stress-stain behaviour of the myocardium. In this work, a numerical model of the canine left ventricle (LV) is presented, which serves to address the limitations of previous studies. A canine LV myocardium material model was developed for use in conjunction with a commercial finite element code. The material model was modified from its original form to make it suitable for use in simulations. Further, numerical constraints were imposed when calculating the material parameter values, to ensure that the model would be strictly convex. An initial geometry and non-zero stress state are required to start cardiac cycle simulations. These were generated by the static inflation of a passive LV model to an end-diastolic pressure. Comparisons with previous measurements verified that the calculated geometry was representative of end diastole. Stresses calculated at the specified end diastolic pressure showed complex spatial variations, illustrating the superiority of the present approach over a specification of an arbitrary stress distribution to an end-diastolic geometry. In the third part of this study, FSI simulations of the mechanics of the LV were performed over the cardiac cycle. Calculated LV cavity pressures agreed well with previous measurements during most of the cardiac cycle, but deviated from them during rapid filling, which resulted in non-physiological backflow. This study is the first one to present a detailed analysis of the temporal and spatial variations of the properties of both the solid and the fluid components of the canine LV. The observed development of non-uniform pressure distributions in the LV cavity confirms the advantage of performing FSI simulations rather than imposing a uniform fluid pressure on the inner surface of the myocardium during solid-only simulations.
76

The Effects of a Novel Endothelin Receptor Antagonist, Macitentan, on Right Ventricular Substrate Utilization and Function in a Sugen5416/Hypoxia Rat Model of Severe Pulmonary Artery Hypertension

Drozd, Katarzyna January 2014 (has links)
Background-Pulmonary artery hypertension (PAH) is characterized by progressive vascular changes causing increased pulmonary resistance and eventual right heart failure (HF). It has been suggested that altered myocardial substrate utilization may be associated with right HF, however these changes have not yet been well characterized. The aim of this study was to evaluate in vivo right ventricular (RV) function and RV glucose and fatty acid metabolism in an experimental model of PAH using non-invasive positron emission tomography (PET) imaging and to investigate the effect of a novel endothelin receptor antagonist, Macitentan, on the development of PAH and RV energetics. Methods and Results-Severe PAH was induced in a total of 11 male Sprague-Dawley rats using a single injection of Sugen5416 followed by chronic hypoxia. The rats were then randomized to treatment or no treatment with Macitentan (30 mg/kg daily) Five and eight weeks post injection, substrate utilization was serially assessed with 2-[18F]fluoro-2-deoxyglucose (FDG) and 4-[18F]fluoro-6-thia-heptadecanoate (FTHA) PET scans for glucose and fatty acid metabolism respectively, and reported as a standardized uptake value (SUV). This data was correlated with in vivo functional measurements with echocardiography and multi gated acquisition scans. The Sugen-hypoxia (SuHx) model resulted in an increase in RV FDG uptake over 8 weeks (SUV control: 1.56 ± 0.38, week 5 SuHx: 4.06 ± 1.90, week 8 SuHx: 4.00 ± 1.60, p<0.005 between control and week 5 SuHx). RV FTHA data showed a trend towards increased uptake with onset of PAH at week 5 SuHx (SUV control: 1.50 ± 0.40, week 5 SuHx: 3.06 ± 1.10, p>0.05). Macitentan significantly decreased RV FDG uptake (SUV week 8 SuHx: 4.00 ± 1.60, week 8 SuHx +ERA: 2.54 ± 0.90, p<0.05). This was associated with improved RV ejection fraction (PAH week 8 untreated: 53.15 ± 9.9% vs PAH week 8 treated: 73.22 ± 4.8%, p<0.01) and improved pulmonary artery pressures measured by pulmonary artery acceleration time (PAH week 8 untreated: 17.32 ± 2.30 ms vs. PAH week 8 treated: 24.38 ± 3.90 ms, p<0.001). There was a strong correlation between increased pulmonary artery pressures and increased RV FDG uptake (r=0.87, p=0.001) as well as a significant inverse relationship between improved RV ejection fraction and decreased RV FDG uptake (r=-0.72, p=0.01). Conclusion-PAH is associated with metabolic changes in the RV, characterized by increased glucose uptake and a trend towards increased RV fatty acid uptake with onset of PAH. Macitentan attenuated RV FDG uptake and significantly increased RV function as well as hemodynamics compared to untreated group.
77

L'évaluation du ventricule droit dans l'hypertension pulmonaire / Right ventricle evaluation in pulmonary hypertension

Boulate, David 20 December 2017 (has links)
L’insuffisance cardiaque droite est la première cause de mortalité des patients atteints d’hypertension pulmonaire (HP). Au début de la maladie, le ventricule droit (VD) opère un remodelage permettant une adaptation à l’augmentation des résistances vasculaires pulmonaires. Au cours de cette adaptation, les caractéristiques morphologiques, fonctionnelles et myocardiques se modifient. L’analyse de ces modifications peut s’appliquer en clinique au niveau du dépistage, de l’évaluation pronostique et du suivi des patients atteints d’HP. Néanmoins, la physiopathologie du passage d’un état compensé à un état décompensé reste à élucider de même que l’identification de nouvelles cibles thérapeutiques ou l’élaboration de méthodes non-invasives d’évaluation du VD restent à développer. L’objectif de cette thèse était d’évaluer un moyen de dépistage de l’HP en échographie cardiaque et d’étudier la physiopathologie de la défaillance ventriculaire droite sur un cœur droit remodelé. Un large rappel des notions d’anatomie, d’embryologie et de physiologie nécessaires à la compréhension des paramètres d’évaluation du VD a été réalisé, puis des études originales publiées et en cours ont été présentées.Une première étude s’est intéressée au dépistage échocardiographique d’une HP chez des patients avec une pathologie pulmonaire avancée. Nous avons montré que la dilatation de l’oreillette droite, du VD et certains paramètres fonctionnels étaient liés à une HP. Lorsque la fuite tricuspidienne était quantifiable (chez 52% des patients), l’évaluation d’autres paramètres du VD n‘améliorait pas le dépistage d’une HP. La présence de paramètres du VD anormaux chez les patients dont la fuite tricuspidienne n’était pas quantifiable n’améliorait pas le dépistage ; 20% des patients sans HP présentaient une dilatation du VD. Une validation extrinsèque chez l’animal avec une obstruction vasculaire pulmonaire modérée et progressive confirmait que la dilatation du VD était un des paramètres les plus précoces quantifiable lors du développement d’une HP. Le développement d’indices non-invasifs du VD plus spécifique d’une l’HP est nécessaire.Une seconde étude, nous avons caractérisé les modifications du VD au cours d’une insuffisance cardiaque droite aigue survenant dans le cadre d’une HP dans une nouveau modèle animal. Le VD était évalué avec des paramètres de courbes pression-volume, d’échocardiographie, de cathétérisme cardiaque droit et par des biomarqueurs circulants. L’analyse anatomopathologique et protéique du VD, environ 3 heures après la restauration hémodynamique, retrouvait des lésions d’ischémie sous-endocardiques et sous-épicardiques et des stigmates d’activation d’autophagie. Nous avons retrouvé des lésions sous-endocardiques du VD similaires chez 5 patients avec une HP ayant bénéficié d’une transplantation cardiopulmonaire dans un contexte de défaillance hémodynamique. Des données préliminaires suggèrent que ces lésions sont associées aux défaillances rénales et hépatiques et à une altération de la survie après transplantation cardiopulmonaire.En conclusion, certains signes de remodelage du VD peuvent être présents chez des patients avec des pathologies pulmonaires avancés en l’absence d’HP, ce qui limite leur intérêt pour le diagnostic non-invasif d’une HP. A l’autre extrémité du spectre de sévérité d’une HP, nous avons modélisé pour la première fois une insuffisance cardiaque droite aigue dans un modèle animal d’HP. Nous avons démontré pour la première fois que des lésions ischémiques pouvaient se développer dans le VD en quelques heures malgré l’induction d’une restauration hémodynamique avec de la dobutamine. Ces données apportent un rationnel fort pour l’évaluation des lésions tissulaires du VD à l’aide de biomarqueurs circulant en pratique clinique dont les applications restent à établir. / Right heart failure is the leading cause of mortality in patients with pulmonary hypertension (PH). At early stage of PH the right ventricle (RV) remodels to adapt to the increased pulmonary vascular resistances. This adaptation is characterized by morphological, functional and myocardial changes. The evaluation of these changes may be applied for screening, prognosis evaluation and follow-up of patients with PH. However, the pathophysiology of the transition from adaptive to maladaptive phenotypes remains unclear; and identification of RV therapeutic targets and noninvasive methods for its evaluation remains to developed. The aim of this thesis was to evaluate non-invasive screening of PH with echocardiography and to study the pathophysiology of acute right heart failure in the setting of chronic PH by performing precise phenotyping of a new large animal model. A wide review of anatomic, embryologic and physiologic concepts was performed to help for the understanding of parameters of RV evaluation; then published and ongoing original studies were presented.In a first study, we investigated PH screening with echocardiography in patients with advanced lung disease. In this study, we showed that enlargement of the RV and of the right atrium, as well as function parameters of the RV were associated with PH. When the tricuspid regurgitation was available (52% of cases), RV morphology and function parameters did not improve PH diagnosis. Abnormal RV morphology and function without available tricuspid regurgitation provided moderate detection value; whereas 20% of patients without PH presented enlargement of the RV. In a large animal model with progressive increase in pulmonary artery mechanical obstruction, enlargement of the RV was the earliest RV parameter associated with PH development. This study highlights the need for more specific RV indices of PH.In a second study we investigated right ventricular changes in a new large animal model of acute right heart failure occurring on chronic PH; a situation associated with around 40% mid term mortality or transplantation. We characterized right ventricular changes during acute volume and pressure overload and after hemodynamic restauration in a large animal model of chronic thromboembolic PH. The RV was evaluated with parameters derived from pressure-volume loops, echocardiography, right heart catheterism and with circulating biomarkers. Pathological and proteins content analyzes of the RV around 3 hours after hemodynamic restauration showed acute subendocardial and subepicardial focal ischemic lesions as well as signs of autophagy activation. We found similar ischemic lesions in RV of 5 patients who underwent a heart-lung transplantation for PH in the setting of hemodynamic compromise. Preliminary data suggest that these lesions are associated with end-organ injury and poor overall survival after heart-lung transplantation in patients with PH.In conclusion, abnormal echocardiographic right heart metrics may be observed in patients with advanced lung disease without PH limiting their use for PH screening in this population. This highlight the need for more specific right heart metrics associated with PH. At the other extreme of the spectrum of PH severity, we described for the first time a large animal model of acute right heart failure in chronic PH. We reproduced and described the main morphological and functional features observed in acute right heart failure on PH and we showed for the first time that acute right ventricular ischemic lesions may develop within few hours despite hemodynamic restauration with dobutamine. These data provide a strong rational to develop specific biomarkers to evaluate tissue lesions of the right ventricle and determine their clinical implications.
78

Du cœur droit normal au pathologique : analyse de la forme et de la fonction dans différentes conditions de charge à l'aide de l’imagerie médicale et de la modélisation / From normal right ventricle to pathology : shape and function analysis with different loading conditions using imaging and modelling

Moceri, Pamela 25 January 2018 (has links)
L’objectif de cette thèse est d'étudier le ventricule droit (VD) dans différentes conditions de charge en utilisant imagerie et modélisation. Le premier axe de ce travail est une étude prospective qui analyse la déformation VD chez des patients sains et avec hypertension pulmonaire (HTP) en utilisant l’échocardiographie trans-thoracique 3D. Les maillages VD ont été obtenus par tracking myocardique et post-traités afin d’extraire le strain de surface. Les correspondances spatiotemporelles ont été vérifiées avant de réaliser les statistiques des maillages. La forme et déformation globale VD sont associées à la sévérité de l'HTP et donnent des informations pronostiques. Le deuxième axe de ce travail présente le rôle d'une évaluation longitudinale par rapport à celui d’une évaluation instantanée, en utilisant la même méthodologie. Nous avons démontré la valeur ajoutée pronostique des modifications dans le temps de déformation VD et l'importance du septum. Dans le troisième axe, les aspects complémentaires de la forme (définie par la courbure) et déformation VD ont été évalués dans des populations de surcharge en volume VD. Alors que forme et déformation sont altérés chez les patients avec tétralogie de Fallot, seule la forme a permis de différencier les patients avec CIA des témoins. Enfin, dans le dernier axe, nous avons étudié la valeur ajoutée de la personnalisation d'un modèle circulatoire 0D pour caractériser la pathologie et prédire la réponse au traitement dans l’hypertension artérielle pulmonaire. Le modèle a été personnalisé pour 11 patients avant et après traitement spécifique de l’HTP. Les paramètres du modèle reflètent bien les changements attendus avec la thérapie. / The aim of this thesis is to study the right ventricle (RV) in different loading conditions using imaging and modelling. The first axis of this work was a prospective study in which we studied RV deformation in healthy controls and pulmonary hypertension (PH) patients (pressure overload) using 3D transthoracic RV echocardiographic sequences. Output RV meshes; obtained after myocardial tracking; were post-processed to extract area strain and spatiotemporal correspondences were checked before computing statistics on these meshes. RV shape and strain patterns were gradually deteriorated with the severity of PH and provided independent prognostic information. The second axis of this work focused on the role of a longitudinal evaluation in comparison with a single assessment at baseline, using the same methodology. We demonstrated the additional prognostic value of changes in RV area strain and the importance of septal segments. In the third axis, we assessed the complementary aspects of RV deformation and shape (using curvature index) in RV volume overload patients. While shape and strain are both altered in tetralogy of Fallot patients, only RV shape allows to differentiate atrial septal defects from normal controls. Finally, in the last axis, we focused on the added value of the personalisation of a 0D circulation model to characterize the pathology and predict the response to therapy in pulmonary arterial hypertension. The model was personalised to 11 PH patient data before and after advanced specific PH therapy. The model parameters reflected accurately the expected changes with therapy.
79

Takotsubo Cardiomyopathy Mimicking Stent Thrombosis After Percutaneous Coronary Intervention

Khattak, Furqan, Khalid, Muhammad, Murtaza, Ghulam, Paul, Timir K. 30 April 2018 (has links)
Takotsubo cardiomyopathy, also known as “broken heart syndrome,” is a transient left ventricular dysfunction associated with stress (usually emotional) induced myocardial injury and stunning. It often presents as myocardial infarction on surface electrocardiogram (EKG). Diagnosis is made by coronary angiography, which rules out coronary artery disease and shows pathognomonic apical ballooning. In this article, we present a case of a 72-year-old woman who initially presented with an ST segment elevation myocardial infarction on EKG. Coronary angiography showed severe left anterior descending artery and diagonal lesions requiring percutaneous coronary intervention. Post–percutaneous coronary intervention, EKG changes resolved. The next day, the patient developed recurrent chest pain and her EKG showed diffuse T-wave inversion in precordial leads with reemerging ST segment elevations concerning for stent thrombosis. The patient underwent repeat emergent coronary angiography, which showed patent stents and findings consistent with takotsubo cardiomyopathy.
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Spatio-temporal dynamics in the anchoring of cilia

Kapoor, Shoba 20 September 2019 (has links)
No description available.

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