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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

The effect of a physical conditioning program on patients with mitral valve prolapse snydrome /

Alexander, Lori Ann January 1980 (has links)
No description available.
22

Outcome after mitral valve surgery for mitral valve regurgitation

Heikkinen, J. (Jouni) 08 January 2008 (has links)
Abstract The repair of degenerative mitral valve regurgitation has been shown to be an effective procedure with durable results. The techniques for mitral valve repair are not completely risk-free for late failure, and the identification of factors associated with this increased risk is of clinical relevance as it permits an appropriate selection of patients for whom mitral valve surgery should be offered and by which technique. The European system for cardiac operative risk evaluation score (EuroSCORE) has been used and demonstrated worldwide to be a valid tool for the prediction of immediate postoperative outcome after coronary artery bypass surgery. There are only a few studies which examine its value in heart valve surgery. Mitral valve repair has been shown to be associated with significant improvement in terms of functional capacity, but the late quality of life in these patients has not been adequately assessed, and there is no data on the quality of life of long-term survivors. The study population consisted of two groups of patients operated on at our institution. The first group included 164 patients who underwent isolated or combined mitral valve repair for mitral valve regurgitation during the period 1993 to 2000, while the second group consisted of 207 patients who underwent mitral valve repair (164 patients) or replacement (43 patients) for isolated mitral valve regurgitation during the same time-period. The first study aimed to identify preoperative variables which may have impact on the 30-day postoperative outcome. In the second study, the long-term outcome after mitral valve repair was evaluated in order to identify the risk factors associated with late failures. The third study analyzed quality of life after valve repair and compared it to that of an age- and gender-adjusted Finnish general population. In the fourth study, the validity of EuroSCORE was tested in predicting the immediate and late outcome of patients who had undergone mitral valve repair or replacement for isolated valve regurgitation. Patient age, a history of prior cardiac surgery and NYHA functional class were independent predictors of poor outcome. A residual regurgitation grade of more than one immediately after primary repair and chronic pulmonary disease were independent predictors of mitral valve reoperation. After valve repair, quality of life was similar to the age- and sex-adjusted general Finnish population. Both additive and logistic EuroSCOREs were predictors of the immediate and late outcomes of patients after surgery for mitral valve regurgitation.
23

Closed mitral valvotomy in pregnancy

Vosloo, S M 31 March 2017 (has links)
Heart disease remains the most important non-obstetric cause of maternal mortality and morbidity during pregnancy, despite its low incidence of less than 1%. This is due to the decline in the number of deaths from haemorrhage, infection and toxemia. In addition, a striking change in the pattern of proportional distribution of organic heart disease in pregnant women is being noted, with a decrease in chronic rheumatic lesions and an increase in congenital cardiac disease. In the Third World rheumatic mitral valve disease remains a most important condition during pregnancy. It is currently rarely seen in Europe and the United States. Mitral stenosis is the most commonly encountered rheumatic heart lesion that complicates pregnancy. The normal circulatory changes during pregnancy aggravate this lesion as the reduced, fixed valve area obstructs blood flow from the left atrium to the left ventricle, causing pulmonary congestion and oedema. Careful and regular follow up of these patients is essential, and surgery is indicated if optimal medical management fails. Cardiac surgery duting pregnancy represents a risk to both the foetus and the mother. For most procedures extracorporeal circulation and heparinization are necessary and adds to the · adverse effects of the operation. Closed mitral valvotomy, however, is an excellent low risk operative procedure in patients with tight mitral stenosis without causing undue harm to the foetus. Cuttler described the first attempted surgery of the mitral valve in 1923 and since then the procedure has been improved to benefit many patients with tight mitral stenosis. The first reports of closed mitral valvotomy during pregnancy were in 1952. Al though a more precise valvotomy can be obtained with an open procedure, the closed operation avoids the risks of extracorporeal circulation, particularly detrimental to the foetus. This report is a review of the Groote Schuur Hospital experience of patients with mitral stenosis requiring closed mitral valvotomy during pregnancy since 1965. The aims of the study are to analyse the outcome of the pregnancy, the effects of valvotomy during pregnancy on both the mother and the foetus, and the outcome regarding restenosis of the mitral valve.
24

Mitral Valve Prolapse: Relationship of Echocardiography Characteristics to Natural History

Mechleb, Bassam, Kasasbeh, Ehab S., Iskandar, Said B., Schoondyke, Jeffrey W., Garcia, Israel D. 01 May 2006 (has links)
No description available.
25

Design, Prototyping and Testing of a Tool for Intracardiac Delivery and Anchoring of a Prosthetic MitraI Valve

Marshall, Eli 25 April 2012 (has links)
The mitral valve in the heart sometimes struggles with diseases and complications, and needs to be replaced. This problem becomes more frequent with the ageing of the population in developed countries. The most common practice consists of suturing a prosthetic valve into place. However, newer methods are being devised and tested to make the surgery faster and less invasive. In particular, various types of new sutureless heart valve systems exist on the market. However, there is still a need for a tool designed for the intracardiac delivery and anchoring of a prosthetic mitral valve, as addressed here. A number of criteria and specifications were set by researchers at the Robarts Research Institute (London, ON) who came up with the design task. To address their request, ten conceptual designs of a sutureless, virtual-reality guided, self-anchoring, intracardiac system were developed to hold a prosthetic mitral valve, deliver it safely, and quickly affix it in position. The winning concept adequately met the design criteria. Two prototypes were manufactured. The attachment of a prosthetic valve to a simulated mitral valve annulus was tested with the first prototype to verify feasibility and measure leakage. The second prototype was pressure tested in a dynamic surgical phantom reproducing the circulatory conditions during surgery. While the preliminary feasibility of the concept was established, recommendations were made to develop a less bulky design.
26

Control mechanism for the papillary muscles of the mitral valve : an In Vitro study

Gieseking, Elizabeth Robinson 08 1900 (has links)
No description available.
27

Stentless mitral valve fixation : impact on hemodynamic performance

Jensen, Morten Ølgaard Jegstrup 05 1900 (has links)
No description available.
28

Design, Prototyping and Testing of a Tool for Intracardiac Delivery and Anchoring of a Prosthetic MitraI Valve

Marshall, Eli 25 April 2012 (has links)
The mitral valve in the heart sometimes struggles with diseases and complications, and needs to be replaced. This problem becomes more frequent with the ageing of the population in developed countries. The most common practice consists of suturing a prosthetic valve into place. However, newer methods are being devised and tested to make the surgery faster and less invasive. In particular, various types of new sutureless heart valve systems exist on the market. However, there is still a need for a tool designed for the intracardiac delivery and anchoring of a prosthetic mitral valve, as addressed here. A number of criteria and specifications were set by researchers at the Robarts Research Institute (London, ON) who came up with the design task. To address their request, ten conceptual designs of a sutureless, virtual-reality guided, self-anchoring, intracardiac system were developed to hold a prosthetic mitral valve, deliver it safely, and quickly affix it in position. The winning concept adequately met the design criteria. Two prototypes were manufactured. The attachment of a prosthetic valve to a simulated mitral valve annulus was tested with the first prototype to verify feasibility and measure leakage. The second prototype was pressure tested in a dynamic surgical phantom reproducing the circulatory conditions during surgery. While the preliminary feasibility of the concept was established, recommendations were made to develop a less bulky design.
29

Developmental pathways and gene function in canine myxomatous mitral valve disease

Lu, Chih Chien January 2015 (has links)
Canine myxomatous mitral valve disease (MMVD) is the most common cardiac disease in dogs affecting all breeds, and it shares many similarities with the equivalent human disease. From the only transcriptomic report for canine MMVD published in 2006, serotonin signalling was identified as a contributing factor and has been widely studied since. Two transcriptomic profiling studies in human MMVD have also identified oxidative stress response and bone morphogenic protein signalling contributing to disease pathology. All studies at the transcriptional level have identified a variety of biological functions in MMVD suggesting dynamic extracellular matrix (ECM) remodelling processes are on-going. Moreover, cellular changes found in MMVD are somewhat reminiscent of the events seen in early heart valve, suggesting possible re-activation of signalling pathways of which those driving development and endothelial-to-mesenchymal transition (EndoMT) are particularly interesting. EndoMT, in which endothelial cells change their identity to mesenchymal phenotype and migrate into the cardiac jelly underneath the endothelium, is a crucial mechanism in valvulogenesis. Whether or not gene regulation of EndoMT and valve development also plays a role in MMVD is unknown. In this study, the MMVD cellular changes in the Cavalier King Charles Spaniel (CKCS), a breed with the highest prevalence, earliest onset, and rapid progression of the disease, was investigated. Secondly, transcriptional profiling was conducted using the latest canine microarray chips, a single affected breed (CKCSs), stringent sample quality control and statistical thresholds, with quantitative polymerase chain reaction (Q-PCR) for data validation. After transcriptional mapping, multi-platform in silico analysis was conducted to identify relationship between differentially expressed genes and their relevant biological functions. Next, a comparison study using immunohistochemistry was performed on different severities of myxomatous valves to localize the proteins of interest. Finally, to model the transcriptional factors and their downstream targets, mitral valve endothelial cell (MVEC) clones were derived from the canine normal mitral valves for future in vitro studies. Cellular changes of MMVD between CKCS and non-CKCS populations showed no difference in their distribution, number and phenotypic markers. Global genomic expression analysis identified similar (inflammation, up-regulation of serotonin receptor and bone morphogenic protein) and novel biological functions (epithelial-to-mesenchymal transition) compared to the previous study in 2006. Key transcriptional factors and genes associated with EndoMT including SNAI1, TAGLN, ACTA2, ACTG2, HAS2, and CTNNB1 were found up-regulated, and NID1, LAMA2, CDH5 were down-regulated in the MMVD group. In myxomatous mitral valves, increased expression of HAS2 in myofibroblasts, SNAI1 expression in endothelial cells, and co-expression of CDH5 and α-smooth muscle actin (α-SMA) also suggested the presence of EndoMT compared to normal valves. Nevertheless, there is also evidence of EndoMT in normal valves (α-SMA positive endothelial cells) which might suggest contribution to life-long valve re-modelling. In addition, there was a decreased expression of microRNAs associated with modulation of extracellular matrix transcripts, including miR-23, miR-29, and miR-218, indicating epigenetic regulation in MMVD. Based on the cellular changes, MMVD in CKCS appears to be representative of MMVD in all breeds and the early-onset of MMVD in that breed does not lead to different end-stage pathology. Novel biological functions such as EndoMT, were identified by transcriptional profiling, and by using powerful bioinformatic tools providing insight into understanding gene regulation in MMVD. Furthermore, a relationship between developmental biology processes and MMVD pathogenesis was established, with a likely important role for epigenetics in disease pathogenesis.
30

Design, Prototyping and Testing of a Tool for Intracardiac Delivery and Anchoring of a Prosthetic MitraI Valve

Marshall, Eli January 2012 (has links)
The mitral valve in the heart sometimes struggles with diseases and complications, and needs to be replaced. This problem becomes more frequent with the ageing of the population in developed countries. The most common practice consists of suturing a prosthetic valve into place. However, newer methods are being devised and tested to make the surgery faster and less invasive. In particular, various types of new sutureless heart valve systems exist on the market. However, there is still a need for a tool designed for the intracardiac delivery and anchoring of a prosthetic mitral valve, as addressed here. A number of criteria and specifications were set by researchers at the Robarts Research Institute (London, ON) who came up with the design task. To address their request, ten conceptual designs of a sutureless, virtual-reality guided, self-anchoring, intracardiac system were developed to hold a prosthetic mitral valve, deliver it safely, and quickly affix it in position. The winning concept adequately met the design criteria. Two prototypes were manufactured. The attachment of a prosthetic valve to a simulated mitral valve annulus was tested with the first prototype to verify feasibility and measure leakage. The second prototype was pressure tested in a dynamic surgical phantom reproducing the circulatory conditions during surgery. While the preliminary feasibility of the concept was established, recommendations were made to develop a less bulky design.

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