Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-04-17T19:32:53Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese final biblioteca.pdf: 1851580 bytes, checksum: 809baa65e670eaa5609551c9d708e7f8 (MD5) / Made available in DSpace on 2017-04-17T19:32:53Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) tese final biblioteca.pdf: 1851580 bytes, checksum: 809baa65e670eaa5609551c9d708e7f8 (MD5) Previous issue date: 2015-11-11 / Introdução: A obesidade é associada com alterações da estrutura e da função do ventrículo esquerdo (VE). A cirurgia bariátrica tem efeitos favoráveis sobre o remodelamento cardíaco, mas seus efeitos sobre as funções diastólica e sistólica do VE ainda não foram claramente definidas. Objetivo: Avaliar as mudanças na estrutura e nas funções diastólica e sistólica do VE em pacientes submetidos à cirurgia bariátrica. Método: Estudo prospectivo, observacional onde foram avaliados 23 pacientes com índice de massa corpórea superior a 40 submetidos à cirurgia bariátrica. As avaliações clínica e ecocardiográfica foram realizadas no período pré-operatório e 3-7 meses após a cirurgia. Resultados: Após um seguimento médio de 4,7 meses, o peso corporal dos pacientes foi significativamente reduzido de 126,3 ± 25 para 97,7 ± 19 kg (p < 0,001) e o índice de massa corporal de 46,7 ± 5,3 para 36,2 ± 4,7 kg/m2 (p< 0,001). A pressão arterial sistólica foi reduzida de 138,6 ± 14,9 para 118,8 ± 8,9 mmHg (p < 0,001) e a pressão arterial diastólica de 85,8 ± 10,4 para 79,7 ± 6,5 mmHg (p 0,002). A avaliação ecocardiográfica mostrou redução na espessura do septo interventricular e da parede posterior do VE (10,3 ± 1,4 para 8,9 ± 1,2 mm e 9,3 ± 1,3 para 8,4 ± 1,1 mm, respectivamente; p < 0,001). Após a cirurgia, houve redução da massa do VE (valor absoluto: 168,7 ± 35,2 para 149,8 ± 40,7 g, p 0,008; valor indexado pela altura: 45,1 ± 11,3 para 39,7 ± 10,3 g/m2,7, p 0,006) e da espessura relativa do VE de 0,39 ± 0,06 pra 0,34 ± 0,04 (p<0,001). A prevalência de geometria normal do VE aumentou de 60,9% antes da cirurgia para 91,3% no seguimento. As medidas obtidas através de Doppler tecidual detectaram melhorias na função diastólica do VE (velocidade de E’ no anel mitral lateral de 0,16 ± 0,03 m/s no período pré-operatório x 0,17 ± 0,03 m/s no seguimento; p 0,026). Não houve diferença significante na função sistólica de VE mensurada através da fração de ejeção e da fração de encurtamento. Conclusão: Cirurgia bariátrica promove melhorias na estrutura e na função diastólica do VE. Não houve modificações nos parâmetros de função sistólica do VE. / Obesity is associated with changes in left ventricular (LV) structure and function. Bariatric surgery can favorably improve cardiac remodeling. The effects of the procedure in LV diastolic and systolic function have not been clearly defined. The aim of this study was to evaluate the changes in left ventricular structure, systolic and diastolic function in obese patients who have undergone bariatric surgery. We evaluated twenty-three patients (16 women, 7 men; 32,9 ± 8,9 years) with body mass index above 40 submitted to bariatric surgery. Clinical and echocardiographic evaluation were performed preoperatively and 3-7 months after the surgery. After a mean follow-up of 4,7 months, body weight was significantly reduced from 126,3 ± 25 to 97,7 ± 19 kg (p < 0,001) and body mass index from 46,7 ± 5,3 to 36,2 ± 4,7 kg/m2 (p< 0,001). Systolic blood pressure was reduced from 138,6 ± 14,9 to 118,8 ± 8,9 mmHg (p < 0,001) and diastolic blood pressure from 85,8 ± 10,4 to 79,7 ± 6,5 mmHg (p 0,002). Echocardiography showed decrease of the interventricular septum and left ventricular (LV) posterior wall thickness (10,3 ± 1,4 to 8,9 ± 1,2 mm and 9,3 ± 1,3 to 8,4 ± 1,1 mm, respectively; p < 0,001). After surgery, there was a reduction in left ventricular mass (LVM) (absolute value: 168,7 ± 35,2 to 149,8 ± 40,7 g, p 0,008; value indexed by height: 45,1 ± 11,3 to 39,7 ± 10,3, p 0,006) and in LV relative wall thickness (RWT) from 0,39 ± 0,06 to 0,34 ± 0,04 (p<0,001). The prevalence of normal left ventricular geometry improved from 60,9% before surgery to 91,3% at follow-up. Tissue Doppler imaging detected improvement in the LV diastolic function (mitral E’ lateral 0,16 ± 0,03 m/s preoperative vs. 0,17 ± 0,03 m/s at follow-up; p 0,026). There was no significant difference in LV systolic function measured by ejection fraction and fractional shortening. Bariatric surgery promotes improvement in left ventricular structure and diastolic function. There were no changes in left ventricular systolic parameters.

<p>QC 20170306</p>

Wang Mei. / "July 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 208-233). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Bibliography: leaves 306-353. / xiii, 353 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Utilizing a paired transcoronary sampling technique, serial determination of myocardial drug content was determined following intravenous bolus injection in patients undergoing diagnostic cardiac catheterization for the investigation of chest pain. There was significant modulation of haemodynamic effects of all three drugs according to changes in systolic interval. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, Queen Elizabeth Hospital, Cardiology Unit

L'état de choc septique est une des principales causes de mortalité hospitalière. Il est caractérisé par une vasoplègie, une tachycardie et s'y associe une défaillance myocardique chez de nombreux patients. Physiologiquement, la tachycardie est non seulement à l'origine d'une augmentation du débit par la multiplication des cycles cardiaques mais elle a de plus des effets propres qui augmentent la contractilité et la relaxation ventriculaire. Ces phénomènes sont appelés relation force-fréquence (FFR) et accélération de la relaxation par la fréquence (FDAR). La défaillance myocardique septique est caractérisée par une altération de la contractilité myocardique mais également par des modifications de la relaxation ventriculaire. Dans un premier temps notre travail a consisté à mettre en évidence la défaillance contractile cardiaque dans un modèle de choc septique par injection d'endotoxine. Il met également en avant l'implication de l'activation des caspases (protéases participant à la voie de l'apoptose) comme étant un des mécanismes de cette défaillance. Ensuite nous avons mis en avant le rôle de médiateurs circulants dans l'apparition de cette dysfonction. L'identité de ces médiateurs est probablement cytokinique. TNF-α et IL-1β ont déjà montré leur capacité à induire cette dysfonction mais dans notre modèle ils n'ont pas été nécessaires à son apparition, d'autres cytokines pourraient être impliquées. Enfin nous avons mis en évidence que cette dysfonction myocardique septique était associée à une altération de FFR et de FDAR et que cette particularité pourrait être liée à une augmentation de l'activité de phosphatases cardiomyocytaires. L'apport de ces connaissances supplémentaires sur les mécanismes impliqués dans le choc septique ne permet pas de modification directe du traitement à proposer aux patients septiques, mais il ouvre de nouvelles voies d'investigation qui pourraient permettre une amélioration des stratégies thérapeutiques du choc septique.

Heart failure is the clinical syndrome accompanying the inability of the heart to maintain a cardiac output required to meet the metabolic requirements and accommodate venous return, and is one of the leading causes of mortality in United States. Accurate imaging of the heart and its failure is important for successful patient management and treatment. Multiple cardiac imaging modalities provide complementary information about the heart – LV function and wall motion, anatomy, myocardial viability and ischemia. In many instances, it is necessary for a patient to undergo multiple imaging sessions to obtain diagnostic clinical information with confidence. It would be beneficial to the individual and the health care system if a single imaging modality could yield reliable clinical information about the heart, leading to a reduced cost, anxiety and an increased diagnostic confidence. This thesis proposes methods that would make cardiac MRI perform an improved assessment of LV function, wall motion, and viability, such that cardiac MRI is taken one step closer to being a single stop solution for imaging of heart. Conventional cardiac MR imaging is performed at a temporal resolution of around 40 ms per cardiac phase. While the global left ventricular (LV) function can be reliably established at this temporal resolution, functional metrics characterizing transient function like peak filling and ejection rates are not accurately assessed. A high temporal resolution is necessary to characterize such transient LV function and wall motion mechanics. This thesis proposes methods to acquire cine-images of the heart at a higher temporal resolution (~ 6 ms) and algorithms to acquire the LV volume across all cardiac phases that would yield functional metrics characterizing LV function and wall motion mechanics. The validation of these algorithms was performed on human subjects. Cardiac MR imaging is the current gold standard of myocardial viability imaging, in which scarred regions of the heart following myocardial infarction are visualized. However viability imaging faces image quality challenges in patients with severe arrhythmias and in cases where a higher spatial resolution, and hence a longer acquisition time, is desired. This thesis also proposes an arrhythmia insensitive inversion recovery (AIIR) algorithm that would significantly reduce artifacts that degrade image quality, thereby extending viability imaging to higher spatial resolution and in patients with severe arrhythmia. Simulations, experimental validation on phantoms and clinical verification on patients are performed. Results from high temporal resolution imaging reveal that obtaining cine cardiac MR images at a temporal resolution of 6 ms per cardiac phase is feasible. Appropriate validated algorithms yield LV time-volume curve from which LV functional metrics are reliably extracted. A dependence on temporal resolution is revealed, and a temporal resolution cut-off of 12 ms is proposed to reliably capture the temporal dynamics of the LV. Also, results from cardiac viability imaging show that the AIIR algorithm performs significantly better than conventional imaging methods in both phantoms and human subjects, as shown by the blinded expert scores, leading to a better image quality. In conclusion, this thesis proposes and implements methods that help cardiac MRI yield 1) a better function and wall motion assessment of the heart through high temporal resolution imaging and 2) a better assessment of myocardial viability through the AIIR algorithm.

This study investigates use of echocardiography to assess the related issues about whether the heart function of a subject examined is normal or not. Two-dimensional echocardiography can make the heart inspection, and provide very detailed informations for each part of the cardiovascular structures with a high degree of accuracy. Many studies indicated that the systolic and diastolic function with left ventricle of heart disease in patients was poorer than those of normal patients. Therefore it is of interest to study the systolic and diastolic function for examining whether there are heart problems. In this work, the data is the gray-scale values of left ventricular static ultrasound images. The gray-scale differences between systolic and diastolic period, are used to assess whether the patient suffers from the heart diseases or not. Here, we use factor analysis to simplify and select the crucial factors, namely the function in different area of the left ventricle. Finally, linear and quadratic discriminant analyses are used to distinguish the normal and the abnormal subjects.

Non-invasive physical examination helps to make disease diagnosis with minimum injury to the body. Cardiology ultrasound is a non-invasive examination which can be used as a auxiliary tool for diagnose cardiac structure abnormalities. With more understanding of heart diseases, it has been recognized that heart failures are closely related to left ventricular systolic and diastolic function. Following Chen (2011) and Kao (2011), we study association of heart diseases with the change of gray-scale values in the cardiology ultrasound images of left ventricular systolic and diastolic. Since data obtained from ultrasound image is of matrix type with high dimensions, following the method proposed by Chen (2011) and Kao (2011), factor scores obtained from factor analysis are used as a basis for classification. We take the factor scores of normal subjects to establish the bench mark and calculate the Mahalanobis distance of each abnormal subject with the model established by the data from normal group. Later based on this distance to the normal group, cardiac function of the subject is distinguished as normal or not. In order to improve the accuracy of the classification, influential points which may cause inaccurate covariance matrix estimate on the subjects in normal group are identified. Based on concepts from optimal designs theory, some criteria are established for screening out the influential points.

published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Medical Sciences