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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.
21

Mechanical and histological disturbances in advanced heart failure and cardiac transplantation

Cameli, Matteo January 2016 (has links)
The general purpose of this thesis is to establish capability and accuracy of speckle tracking echocardiography (STE) in assessing left atrial (LA), left ventricular (LV) and right ventricular (RV) function and their correlation with myocardial fibrosis, filling pressure and clinical outcomes in advanced heart failure (HF) patients before and after heart transplantation (HT). I demonstrated that HT recipients had impaired LV twist dynamics in the form of reduced rotation twist angle and untwist rate but time to peak twist was not different from the age matched controls and other cardiac surgical patients. With a longitudinal study conducted on patients with refractory HF, the best prognostic power has been shown by RV strain analysis. Among the indexes of LV function, the LV ejection fraction (LVEF) demonstrated the lowest diagnostic accuracy; instead LV global circumferential strain (GCS) showed a better sensitivity and specificity than LV global longitudinal strain (GLS). When analyzing the relationship between different severity of myocardial fibrosis and LV cavity function, the strongest function parameter that correlated with severity of myocardial fibrosis was GLS. In contrast, none of diastolic LV function or even measures of exercise capacity correlated with myocardial fibrosis. In patients with end-stage HF, global peak atrial longitudinal strain (PALS), an index of atrial reservoir function was dependent by pulmonary capillary wedge pressure (PCWP) and LV fibrosis, but not influenced by LV systolic function. Results from this study confirm previous evidence of correlation between impaired global PALS and increased PCWP.
22

The Relationship Between Maximal Aerobic Capacity and Left Ventricular Function with Respect to Age

Page, Kimberly Ann 12 1900 (has links)
In this study, the relationship between maximal aerobic capacity (VO₂max) and left ventricular function was examined in two distinct age groups. A young group (20 - 30 years of age) and an elderly group (over 60 years of age) were compared. Left ventricular function was examined over wide variations in preload accomplished by 5º head-down tilt (TILT) for ninety minutes and lower body negative pressure (LBNP) to -40 mm Hg. with two-dimensional echocardiography. A greater response to an increase in preload (TILT) was related to high VO₂max levels in the young subjects but not in the elderly groups of subjects, suggesting that lower VO₂max levels of the elderly population affected the mechanism of response to the increased levels of preload. Additionally, in the elderly, greater reductions in ventricular volume reflected increased peripheral pooling due to decreased venous tone and/or increased venous compliance during LBNP and were related to increased VO₂max. In the young, VO₂max does not appear to affect the response to reduced preload.
23

Evolução da hipertrofia miocárdica associada à gestação em mulheres hipertensas após seis meses do parto

Vasconcelos, Milena Miranda January 2019 (has links)
Orientador: Silméia Garcia Zanati Silméia Garcia Bazan / Resumo: Fundamento: A hipertensão arterial sistêmica (HAS) é um dos principais fatores de risco para o desenvolvimento de doença cardiovascular. Quando a mulher hipertensa engravida, ocorre uma nova condição hemodinâmica, com adição da situação de sobrecarga crônica de pressão à situação de sobrecarga crônica de volume. Essa nova condição hemodinâmica pode propiciar maior hipertrofia miocárdica (HVE), sendo que sua evolução após o parto ainda é pouco estudada na literatura. Suspeita-se que as mulheres hipertensas que apresentaram HVE durante gestação mantenham essa alteração cardíaca após o parto. Objetivos: Avaliar a hipertrofia miocárdica em mulheres hipertensas no terceiro trimestre da gestação e após seis meses do parto e estabelecer quais variáveis clínicas estão associadas com risco aumentado de hipertrofia miocárdica. Métodos: Estudo prospectivo longitudinal incluindo 41 mulheres gestantes com idade gestacional acima de 35 semanas e com diagnóstico prévio de HAS, acompanhadas no Ambulatório de Pré-Natal de Hipertensão Arterial do Serviço de Obstetrícia do Hospital das Clínicas da Faculdade de Medicina de Botucatu - UNESP. Foram submetidas às avaliações clínica e ecocardiográfica em dois momentos, período gestacional e período de seis meses após o parto. A HVE foi definida para índice de massa do ventrículo esquerdo indexada pela altura (IMVE) ≥ 45g/m2,7. Análise estatística: regressão logística multivariada com as exposições mais fortemente associadas com a manutenção da HVE n... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Background: Systemic arterial hypertension (SAH) is one of the principal risk factors for developing cardiovascular disease. When a hypertensive woman becomes pregnant, a new hemodynamic condition is installed, with addition from chronic pressure overload to chronic volume overload. This new hemodynamic condition can provides greater myocardial hypertrophy (LVH), whose postpartum evolution has been little studied in the literature. It is suspected that hypertensive women who presented LVH during pregnancy maintain this cardiac alteration after delivery. Objectives: To evaluate myocardial hypertrophy in hypertensive women in the third trimester of pregnancy and six months after delivery and to establish which clinical variables are associated with elevated risk of myocardial hypertrophy. Methods: Prospective longitudinal study including 41 pregnant women beyond 35 gestational weeks and with previous SAH diagnosis, monitored at the Hypertension Clinic of the Obstetrics Unit of the Botucatu School of Medicine - UNESP. They were submitted to clinical and echocardiographic evaluation at two moments, the gestational period and six months postpartum. LVH was defined for the left ventricular mass index as (LVMI) ≥ 45g/m2.7. Statistical analysis: multivariate logistic regression with the exposures most strongly associated with maintenance of hypertrophy in univariate analysis. Significance level: p<0.05. Results: The mean age was 29±6.2 years; mean gestacional age was 36.7±1.18 weeks;... (Complete abstract click electronic access below) / Mestre
24

Non-invasive assessment of left ventricular diastolic function: the impact of systole on diastole. / CUHK electronic theses & dissertations collection

January 2002 (has links)
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.
25

Surgical treatment in chronic aortic regurgitation : Timing, results, prognosis and left ventricular function

Tamás, Éva January 2008 (has links)
Chronic aortic regurgitation (AR) of varying degree affects 13% of men and 8.5% of women. In persons with severe AR, the expected length of life and its quality are influenced. Some individuals remain asymptomatic for a long period, due to effective compensatory mechanisms, but dysfunction of the left ventricle (LV) usually begins before symptoms appear and can be irreversible by then. This thesis addresses questions of LV function and optimal time for operation of patients suffering from chronic AR. Moreover, detailed echocardiographic studies of the anatomy of the normal aortic valve have been performed to obtain a better understanding of the in vivo anatomic relations within the aortic root. Patients with chronic AR, without concomitant cardiac disease, were studied both retrospectively (n=88) and prospectively (n=29) and the aortic valves of persons (n=32) free from cardiac disease were investigated. For the retrospectively studied patients, survival was 82% at 10 years which is an improvement compared with previously published results. The majority of the patients, however, had LV dysfunction preoperatively. By studying patients prospectively by echocardiography, radionuclide ventriculography (MUGA) and cardiopulmonary exercise testing (CPET) our aim was to evaluate the predictive value of measurements of LV function at rest and during exercise for postoperative outcome. LV diameters were markedly elevated prior to and diminished significantly after surgery. Patients with an abnormal exercise ejection fraction (EF) response by MUGA preoperatively, presented the same reaction postoperatively. This could not be predicted by LV function determination at rest, or by NYHA functional class. In spite of median NYHA class II, these patients had a low work capacity on CPET, which was neither improved 6 months postoperatively nor correlated to echocardiographic LV dimensions. Thus, both MUGA and CPET may be useful complements for timing of surgery in patients with chronic AR. Assuming that patients would benefit from preservation of their native valves the normal aortic valve was studied to gain detailed information about the echocardiographic anatomy and relations within the normal aortic root. This extended examination of the aortic root may facilitate a better planning of aortic valve‐preserving interventions in the future.
26

Insights into the effect of myocardial revascularisation on electrical and mechanical cardiac function

Ramzy Guirguis, Ihab January 2012 (has links)
Background: Acute coronary syndrome is known for its effect on cardiac function and can lead to impaired segmental and even global myocardial function. Evidence exists that myocardial revascularisation whether pharmacological, interventional or surgical results in improvement of systolic and diastolic left ventricular (LV) function, particularly that of the long axis which represents the sub-endocardial function, known as the most sensitive layer to ischaemia. Objective: We sought to gain more insight into the early effect of pharmacological and interventional myocardial revascularisation on various aspects of cardiac function including endocrine, electrical, segmental, twist, right ventricular (RV) and left atrial (LA) function. In particular, we aimed to assess the response of ventricular electromechanical function to thrombolysis and its relationship with peptides levels. We also investigated the behaviour of RV function in the setting of LV inferior myocardial infarction (IMI) during the acute insult and early recovery. In addition, we aimed to assess in detail LA electrical and mechanical function in such patients. Finally, we studied the early effect of surgical revascularisation on the LV mechanics using the recent novel of speckle tracking echocardiography technology to assess rotation, twist and torsion and the strain deformation parameters as a tool of identifying global ventricular function. Methods: We used conventionally Doppler echocardiographic transthoracic techniques including M-mode, 2-Dimentional, myocardial tissue Doppler, and speckle tracking techniques. Commercially available SPSS as a software was used for statistical analysis. Results: 1-The elevated peptide levels at 7 days post-myocardial infarction correlated with the reduced mechanical activity of the adjacent non-infarcted segment thus making natriuretic peptides related to failure of compensatory hyperdynamic activity of the non-infarcted area rather than the injured myocardial segments. 2-RV segmental and global functions were impaired in acute IMI, and recovered in 87% of patients following thrombolysis. In the absence of clear evidence for RV infarction the disturbances in the remaining 13% may represent stunned myocardium with its known delayed recovery. 3-LA electromechanical function was impaired in acute inferior STEMI and improved after thrombolysis. The partial functional recovery suggests either reversible ischaemic pathology or a response to a non-compliant LV segment. The residual LA electromechanical and pump dysfunction suggest intrinsic pathology, likely to be ischaemic in origin. 4-LV function was maintained in a group of patients with multivessel coronary artery disease who underwent coronary artery bypass graft (CABG) surgery. Surgical myocardial revascularisation did not result in any early detectable change in the three functional components of the myocardium, including twist and torsion, as opposite to conventional percutaneous coronary intervention (PCI). Conclusion: The studied different materials in this thesis provide significant knowledge on various aspects of acute ischaemic cardiac pathology and early effect of revascularisation. The use of non-invasive imaging, particularly echocardiography with its different modalities, in studying such patients should offer immediate thorough bed-side assessment and assist in offering optimum management.
27

Transoesophageal and transthoracic recordings of mitral annulus motion /

Nilsson, Bo, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.
28

Cardiac memory studies in two human models /

Wecke, Liliane, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.
29

Effects of prostate cancer and exercise training on left ventricular function and cardiac and skeletal muscle mass

Baumfalk, Dryden Ray January 1900 (has links)
Master of Science / Department of Kinesiology / Brad J. Behnke / Prostate cancer is the most common type of non-skin cancer found in men and preliminary evidence suggests prostate cancer has atrophic effects on cardiac and left ventricle (LV) mass which are associated with reduced endurance exercise capacity in rats. Using a pre-clinical orthotopic model of prostate cancer, echocardiography was utilized to test the hypothesis that exercise training will mitigate prostate cancer induced-cardiac and skeletal muscle atrophy and improve LV function versus sedentary tumor-bearing counterparts. Methods: Dunning R-3327 AT-1 prostate cancer cells were injected orthotopically in male Copenhagen rats aged (n=39; ~5 mo. old). Animals were randomized into four groups, exercise-trained tumor-bearing (EXTB) or control (EXCON) and sedentary tumor-bearing (SEDTB), or control (SEDCON). Exercise training was performed via a rodent treadmill set at 15m/min with a 15° incline for 60 min/day for ~30 days. Animals underwent echocardiographic evaluation using the parasternal short axis view to examine ventricle dimensions pre-cancer or exercise (PRE) and 15 (Post 1) and 30 (Post 2) days post cancer cell injection and/or exercise training with tissues collected immediately after Post 2. Results: Cardiac and LV mass of SEDTB animals were significantly lower than all groups (p<0.05). Tumor mass was significantly negatively correlated with LV mass in EXTB (-0.75, p<0.02) and SEDTB animals (-0.72, p<0.02). EXCON group had significantly higher stroke volume Post 2 assessment compared to both sedentary groups (p<0.05), but not EXTB animals. Conclusion: The current investigation demonstrates prostate cancer independent of anti-cancer treatment significantly reduces cardiac mass, and LV mass as well as locomotor muscle masses. However, moderate intensity exercise training can mitigate cardiac and skeletal muscle atrophy with prostate cancer.
30

Avaliação da função ventricular pelo ecocardiograma no pós operatório imediato de pacientes submetidos a cirurgia cardíaca pediátrica

Oliveira Júnior, Francisco Sávio de 22 March 2013 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2015-01-16T17:12:32Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Francisco Sávio de Oliveira Júnior - 2013.pdf: 1465890 bytes, checksum: 171795d1e90b4a8d89f6483685414ca1 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2015-01-16T17:37:12Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Francisco Sávio de Oliveira Júnior - 2013.pdf: 1465890 bytes, checksum: 171795d1e90b4a8d89f6483685414ca1 (MD5) / Made available in DSpace on 2015-01-16T17:37:12Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Francisco Sávio de Oliveira Júnior - 2013.pdf: 1465890 bytes, checksum: 171795d1e90b4a8d89f6483685414ca1 (MD5) Previous issue date: 2013-03-22 / The ventricular dysfunction is one of the most common complications and one of the greatest challenges in conducting of the patient undergoing pediatric cardiac surgery. Understanding the factors that trigger the development of ventricular function and dysfunction postoperatively is critical to the proper management. The aim of this study was to evaluate ventricular systolic function by echocardiography over the first 48 hours of patients undergoing cardiac surgery for biventricular correction. We evaluated 34 patients with a mean age of 18.6 ± 15.6 months, undergoing cardiac surgery with cardiopulmonary bypass. Clinical analysis performed over the 48 hours, incluinding the measurement of NT-pro-BNP, troponin and serum lactate in the first 2 hours, were beyond the quantification of inotropic score and CPB time. Echocardiography was performed at 2 hours, 12 hours, 24 hours and 48 hours after admission to the ICU and the pediatric parameters analyzed were LV ejection fraction, the myocardial performance index of LV and RV tissue Doppler systolic velocity of the lateral wall LV and RV (S wave) and cardiac index. The sequential evaluation of left ventricular systolic function in the first 48 hours after surgery showed no variation, was observed only increase in ejection fraction of the left ventricle (P = 0.008), and variation is limited to the comparison between measures at 24 and 48 hours (P Bonferroni = 0.04). Analysis of right ventricular function did not vary over the 48 hours. Despite the failure to detect the change in the trend function has been observed that the MPI`s RV and LV remained changed along the 48hs.There was no correlation between the myocardial performance index of the right ventricle and the left ventricle with a time of extracorporeal circulation. There was no correlation between the measures of surgical stress and echocardiographic parameters measured two hours after surgery. The echocardiographic variables that assessed right and left ventricular function were within the normal range and showed no significant variation over the first 48 hours after cardiac surgery. / A disfunção ventricular é uma das complicações mais frequentes e um dos maiores desafios na condução do paciente submetido a cirurgia cardíaca pediátrica. Identificar os fatores desencadeantes da disfunção ventricular e a evolução da função ventricular no pós-operatório é fundamental para o manejo adequado. O objetivo desse estudo foi avaliar a função ventricular através do ecocardiograma dos pacientes submetidos a cirurgia cardíaca para correção biventricular ao longo das primeiras 48hs. Foram avaliados 34 pacientes, com a idade média de 18,6 ± 15,6 meses, submetidos à cirurgia cardíaca com circulação extra-corpórea. Realizada análise clínica ao longo das 48hs, dosagem do NT-pro-BNP, troponina e lactato séricos nas primeiras 2hs, além da quantificação do score inotrópico e do tempo de CEC. O ecocardiograma seriado foi realizado com 2hs, 12hs, 24hs e 48hs após a admissão na UTI-pediátrica e os parâmetros analisados foram a fração de ejeção de VE, o índice de performance miocárdica do VE e VD, a velocidade sistólica ao Doppler tecidual da parede lateral do VE e do VD (onda S) e o índice cardíaco. A avaliação sequencial da função sistólica do ventrículo esquerdo nas primeiras 48hs após a cirurgia não mostrou variação, observado apenas aumento da fração de ejeção do ventrículo esquerdo (P = 0,008), variação esta limitada à comparação entre as medidas de 24 horas e 48 horas (P de Bonferroni = 0,04). A análise da função ventricular direita não mostrou variação ao longo das 48hs. Apesar da não detecção da alteração da tendência da função, foi observado que o IPM do VD e VE permaneceu alterado ao longo das 48hs. Não houve correlação entre o índice de performance miocárdica do ventrículo direito e do ventrículo esquerdo com o tempo de circulação extra-corpórea. Não houve correlação entre as medidas de estresse cirúrgico e os parâmetros ecocardiográficos medidos duas horas após cirurgia. As variáveis ecocardiográficas que avaliaram a função ventricular direita e esquerda ficaram dentro do limite de normalidade e não apresentaram variação significativa ao longo das primeiras 48hs após cirurgia cardíaca.

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