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Mitral valve prolapse in Chinese陳維智, Chen, Wai-chee, Walter. January 1982 (has links)
published_or_final_version / Medicine / Master / Doctor of Medicine
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Annular flattening in mitral valve prolapse / CUHK electronic theses & dissertations collectionJanuary 2015 (has links)
Mitral valve (MV) prolapse (MVP) is the most common cause of surgical mitral regurgitation (MR) in developed countries. The normal mitral annulus is saddle in shape, connecting the left atrium (LA) and left ventricle (LV) into a functional entity, and is susceptible to distortion by LA and LV remodeling. Annular nonplanarity is important for alleviating mechanical stress on mitral leaflets and chordae tendinae. Recently, loss of annular saddle shape has been demonstrated as a novel mechanism in the pathogenesis of degenerative MR. Hitherto, the prevalence and features of annular flattening have not been well assessed in MVP patients, as well as potential factors related to annular flattening. / Current guidelines recommend MV repair as the preferred treatment for clinically significant MR. Annuloplasty are routinely used to restore the annular structure and function. Recent long-term studies showed that anterior leaflet or bileaflet prolpase was associated with suboptimal outcomes. However, the relation between mitral leaflets and annular geometry in MVP is not completely understood. / The application of two-dimensional (2D) echocardiography (ECHO) has been limited since mitral annulus has a nonplanar configuration. Three-dimensional (3D) ECHO was shown to be superior to 2D in defining the anatomy of MVP. In this thesis, MVP was identified as systolic displacement (≥2 mm) of any segment of mitral leaflets into the LA passing the mitral annular plane, as indicated in a long axis view (parasternal or apical three-chamber). Finally, 117 MVP patients consecutively referred to our echo laboratory for transesophageal echocardiography (TEE) were retrospectively studied. Twenty-nine patients referred for TEE for suboptimal transthoracic images, exclusion of endocarditis, or evaluation of cardiac source of embolic event and found to have no underlying structural cardiac disease or arrhythmia were included as the normal reference. Standard 2D transthoracic ECHO and 2D/3D TEE were performed in all the subjects. Custom software was used for quantification of 3D MV morphology and key geometric parameters, including mitral annulus, leaflets and chordae, were automatically measured. / The main findings were as follows: / 1. Annular saddle shape flattening (annular height to commisural width ratio <15%) was a common abnormality in MVP patients. More than 50% MVP patients had annular flattening. / 2. Atrial fibrillation (AF) and mitral annular disjunction (MAD) were found to be independent factors associated with annular flattening. MAD was associated with more severe myxomatous MV changes with excessive traction on papillary muscle. The potential roles of MAD in the development of myxomatous MV disease may be through excessive mobility of the mitral apparatus or disturbing 3D annular configuration with reduced annular height and loss of the saddle shape. / 3. Annular flattening was associated with advanced myxomatous MV changes and a higher prevalence of complex prolapse (anterior leaflet and/or bileaflet prolapse). Complex prolapse was associated with more severe annular flattening and dilation, leaflets elongation, increased billow volume and impaired mitral-aortic coupling. / In summary, this thesis provided new data of the 3D MV geometry in MVP patients with new insights into the mechanisms of disease progression and strategies to improve surgical outcomes. Using new techniques in 3D TEE, the thesis demonstrated that annular flattening is a common abnormality, associated with AF, MAD, and more advanced, complex lesions, with implication in the complexity and timing of MV repair. The results suggested that annuloplasty with saddle-shaped rings may be important to restore the structure and function of MV and to improve the durability of repair, particularly important for complex lesions. These data also implied that maintenance of sinus rhythm may help to prevent annular flattening and progression of MVP-related MR. Finally, MAD may be an echocardiographic marker of annular flattening and may require specific surgical correction. / 在發達國家,需要外科治療二尖瓣反流(MR)最常見的原因是二尖瓣脫垂(MVP)。正常二尖瓣瓣環是一個非平面的馬鞍型結構,連接左心房和左心室使之成為一個功能性整體,其結構和功能易受到心房和心室重構的影響。馬鞍型瓣環有助於降低瓣葉和腱索的機械性壓力。最新研究表明瓣環馬鞍型結構缺失是MVP患者出現退行性MR的發病機制。但沒有研究評估瓣環扁平在MVP患者中的患病率,相關特征性改變及引起瓣環扁平的因素。 / 目前,指南推薦二尖瓣修复術作為伴有嚴重MR的脫垂病人的首選治療方法。二尖瓣修复術中常規使用瓣環成形術有助於恢復瓣環的結構和功能。臨床研究顯示脱垂累及前葉或雙葉的手术预后不理想。目前尚不清楚瓣葉和瓣環幾何結構之間存在的相互關係。 / 由於瓣環的非平面結構,三維超聲評估二尖瓣脫垂的價值優於二維超聲。在本研究中,二尖瓣脫垂被定義為長軸水平(胸骨旁長軸或者心尖三腔切面)二尖瓣瓣葉的任何部分發生收縮期向左房面移位,并超過瓣環水平2毫米以上。最後,我們回顧性地研究了117名被轉診到我們心臟超聲實驗室進行經食道超聲檢查的MVP病人。本研究同時入組了29名无其他潛在結構性心臟病或心律不齊的正常對照。他們由於欠佳的經胸超聲圖質量,或者為了排除心內膜炎,或者為了評價血栓是否來自心臟接受了经食道超聲檢查。所有研究對象均接受了標準的二維經胸超聲及二維/三維經食道超聲檢查。研究採用專業軟件對受試者二尖瓣的三維形態進行定量分析。該軟件可自動測量二尖瓣的重要幾何學參數,包括瓣環,瓣葉和鍵索。 / 研究的主要發現包括: / 1.瓣環扁平(瓣環高度與連合線長度之比不超過15%)是一種常見的解剖學異常,超過50%MVP的患者罹患該種畸形。 / 2. 房顫和二尖瓣瓣環分離是引起瓣環扁平的獨立影響因素。瓣環分離與較嚴重的黏液樣改變以及過多的乳頭肌牽拉相關,其在黏液樣二尖瓣疾病中的作用可能是通過引起二尖瓣裝置的過度移動,或通過降低瓣環的高度導致馬鞍形結構缺失從而破壞二尖瓣裝置正常三維幾何學結構。 / 3. 瓣環扁平與嚴重的黏液樣改變有關,同時合併高比例的複雜脫垂(前葉和/或雙葉脫垂)。複雜脫垂與嚴重瓣環扁平和擴大,瓣葉冗長及隆起容積增加相關,同時破壞了二尖瓣-主動脈瓣耦合。 / 總之,本文對MVP疾病進展的機制提出了新的見解,并為手術治療提供有效的策略。本文採用三維經食道超聲領域中最新的成像和圖像分析技術并發現在MVP患者中瓣環扁平是一種常見解剖學發現,其發病與房顫,瓣環分離及嚴重和複雜病變有明確的相關性。這些發現有助於病變複雜程度分級和確定手術時間。採用馬鞍形瓣環成形術既可以修復二尖瓣的結構和功能又能提高修复的持久性。其重要性在複雜MVP患者中尤為明顯。盡早復律可預防瓣環馬鞍形結構缺失和防止反流的加重。最後瓣環分離可作為检测瓣環扁平的超聲學指標,可能需要特殊的外科矯正。 / Jin, Chunna. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 152-165). / Abstracts also in Chinese. / Title from PDF title page (viewed on 12, September, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
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Multimodal treatment of women with mitral valve prolapse syndromeNevin, Doris Eileen Jacobs January 1997 (has links)
Mitral valve prolapse is the most commonly occurring cardiac condition. It is a benign condition which affects as many as 10% of the population. Some patients have symptomatic mitral valve prolapse. This condition is referred to as mitral valve prolapse syndrome. Symptoms include: chest pain, tachycardia, palpitations, fatigue, dizziness, shortness of breath, headaches, low exercise tolerance, feelings of anxiety, panic attacks, and mood swings. These symptoms adversely effect the patient's quality of life.The purpose of this study was to investigate the response of patients with mitral valve prolapse syndrome to treatment that includes the accepted treatment for panic disorder, and to determine the roles of self-efficacy and of level of spousal support in enhancing the ability of identified patients to cope with mitral valve prolapse syndrome.Thirty-one subjects initially agreed to participate in this study. Of these subjects, fifteen left the study. The leading causes of dropout were lack of spousal support and multiple role stress. The remaining sixteen subjects completed the study. Subjects were randomly divided into three treatment conditions, individual multimodal therapy, couples multimodal therapy, and a waiting list/control group. Treatment consisted of attending a five session psychoeducational program and completing prescribed exercises at home between sessions. The first two sessions examined self-care lifestyle changes that patients could make to alleviate symptoms. The remaining three sessions focused on the over reactiveness of the autonomic nervous system for these patients and the efficacy of learned relaxation procedures. Dependent measures included a Symptom Checklist, Anxiety Sensitivity, Strength and Magnitude of Self-Efficacy and Strength and Magnitude of Interactive Efficacy.Data was analyzed in a two-step process. First, it was analyzed using a multiple single case design format. This was followed by a quantitative analysis of grouped data. In general, the multiple single case design complemented the quantitative analysis. Individual findings in the multiple single case design indicated issues for future research.Participation in treatment was found to aid in decreasing global physical symptoms, decreasing anxiety sensitivity symptoms, and increasing the subject's confidence in her ability to manage her symptoms. The increased level of self-confidence was related significantly to decreasing global physical symptoms. There was a weak, non-statistically significant correlation between increased confidence of self-efficacy and decreased anxiety sensitivity symptoms. Participation in couples multimodal treatment or any treatment was not significantly linked to increased interactive efficacy. Increased interactive efficacy was correlated with increased self-efficacy and decreased global physical symptoms. / Department of Counseling Psychology and Guidance Services
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The effects of aerobic exercise training on symptomatic females with mitral valve prolapse syndrome /Scordo, Kristine A. Bludau January 1990 (has links)
No description available.
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Desenvolvimento de técnica de medição e obtenção de dados experimentais envolvidos no ciclo de trabalho dos compressores herméticos alternativos / Development of techniques to measure and extract experimental data of hermetic compressor work cycleReal, Marcelo Alexandre 20 December 2005 (has links)
Essa dissertação desenvolve e faz uso de uma técnica de medição com objetivo de obter dados experimentais envolvidos no ciclo de trabalho dos compressores herméticos alternativos, largamente utilizados nos sistemas de refrigeração. O trabalho mostra o comportamento das válvulas de admissão e descarga durante o funcionamento do compressor, as pressões no cilindro, na sucção, na descarga e também a variação de rotação do eixo durante um ciclo de compressão completo. Todas as características mensuradas estão referenciadas à posição angular do eixo do compressor, o que permitiu monitorar todos os eventos em função do seu deslocamento angular. Para o desenvolvimento desse trabalho foi necessário planejar um sistema de medição robusto, não vulnerável aos fatores ambientais, presentes dentro da carcaça do compressor. A limitação do espaço físico foi um fator de grande importância na escolha dos sensores, assim como a velocidade de resposta dos instrumentos, pois um ciclo de compressão tem período menor que 0,020 segundos. A coleta dos dados e a análise dos sinais foram realizadas com o auxilio de hardware apropriado e software especialmente desenvolvido. / In this dissertation it is developed and applied measurement methods to obtain experimental data of a hermetic compressor work cycle, widely used in the refrigeration systems. This work shows the suction and discharge valve behaviors, the pressure in the cylinder, as well as in the discharge and suction chambers, and also crankshaft rotation variation during a complete compression cycle. All the measurements are reference to crankshaft angular position of compressor which allows to verify the events as a function of the crankshaft angular displacement. For the development of this work it was necessary to plan a reliability measure system, not affected by environmental factors inside the housing of compressor. The inner space limitation was an important feature for choosing the sensors as well as their time response, since the period compression cycle is less than 0.020 seconds. The data acquisition and signal analysis were done with appropriate hardware and it was developed a specific software.
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Desenvolvimento de técnica de medição e obtenção de dados experimentais envolvidos no ciclo de trabalho dos compressores herméticos alternativos / Development of techniques to measure and extract experimental data of hermetic compressor work cycleMarcelo Alexandre Real 20 December 2005 (has links)
Essa dissertação desenvolve e faz uso de uma técnica de medição com objetivo de obter dados experimentais envolvidos no ciclo de trabalho dos compressores herméticos alternativos, largamente utilizados nos sistemas de refrigeração. O trabalho mostra o comportamento das válvulas de admissão e descarga durante o funcionamento do compressor, as pressões no cilindro, na sucção, na descarga e também a variação de rotação do eixo durante um ciclo de compressão completo. Todas as características mensuradas estão referenciadas à posição angular do eixo do compressor, o que permitiu monitorar todos os eventos em função do seu deslocamento angular. Para o desenvolvimento desse trabalho foi necessário planejar um sistema de medição robusto, não vulnerável aos fatores ambientais, presentes dentro da carcaça do compressor. A limitação do espaço físico foi um fator de grande importância na escolha dos sensores, assim como a velocidade de resposta dos instrumentos, pois um ciclo de compressão tem período menor que 0,020 segundos. A coleta dos dados e a análise dos sinais foram realizadas com o auxilio de hardware apropriado e software especialmente desenvolvido. / In this dissertation it is developed and applied measurement methods to obtain experimental data of a hermetic compressor work cycle, widely used in the refrigeration systems. This work shows the suction and discharge valve behaviors, the pressure in the cylinder, as well as in the discharge and suction chambers, and also crankshaft rotation variation during a complete compression cycle. All the measurements are reference to crankshaft angular position of compressor which allows to verify the events as a function of the crankshaft angular displacement. For the development of this work it was necessary to plan a reliability measure system, not affected by environmental factors inside the housing of compressor. The inner space limitation was an important feature for choosing the sensors as well as their time response, since the period compression cycle is less than 0.020 seconds. The data acquisition and signal analysis were done with appropriate hardware and it was developed a specific software.
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