No description available.

yes / To investigate cerebrospinal fluid (CSF) dynamics in the aqueduct of Sylvius (AoS) in chronic cerebrospinal venous insufficiency (CCSVI)-positive and -negative healthy individuals using cine phase contrast imaging. Materials and Methods Fifty-one healthy individuals (32 CCSVI-negative and 19 age-matched CCSVI-positive subjects) were examined using Doppler sonography (DS). Diagnosis of CCSVI was established if subjects fulfilled ≥2 venous hemodynamic criteria on DS. CSF flow and velocity measures were quantified using a semiautomated method and compared with clinical and routine 3T MRI outcomes. Results CCSVI was associated with increased CSF pulsatility in the AoS. Net positive CSF flow was 32% greater in the CCSVI-positive group compared with the CCSVI-negative group (P = 0.008). This was accompanied by a 28% increase in the mean aqueductal characteristic signal (ie, the AoS cross-sectional area over the cardiac cycle) in the CCSVI-positive group compared with the CCSVI-negative group (P = 0.021). Conclusion CSF dynamics are altered in CCSVI-positive healthy individuals, as demonstrated by increased pulsatility. This is accompanied by enlargement of the AoS, suggesting that structural changes may be occurring in the brain parenchyma of CCSVI-positive healthy individuals

INTRODUÇÃO: O conhecimento anatômico desempenha importante papel no desenvolvimento de técnicas diagnósticas e cirúrgicas. Com esse objetivo, na área cardiológica, se mostra fundamental para o entendimento do processo de remodelamento cardíaco que acompanha as cardiomiopatias dilatadas (CMD) tanto isquêmicas (CMDIsq) como idiopáticas (CMDId), de modo particular do ventrículo esquerdo (VE) e sua correlação com alterações do anel atrioventricular esquerdo, levando a graus variáveis de insuficiência cardíaca (IC). OBJETIVOS: Os objetivos desta pesquisa são: 1) Obter medidas do anel atrioventricular esquerdo (mitral) e do ventrículo esquerdo em corações normais, com CMDIsq ou CMDId, comparando-as entre si; 2) Analisar a proporcionalidade entre segmentos da câmara ventricular esquerda dos corações com CMDIsq ou CMDId em relação ao normal; 3) Determinar a esfericidade ou não da câmara ventricular esquerda nos corações com CMDIsq ou CMDId. MÉTODO: Foram analisados 43 corações humanos, divididos em três grupos: NORMAL (n=10), CMDIsq (n=15) e CMDId (n=18). De posse da medida da distância do sulco atrioventricular posterior até o ápice do VE, foram realizados cortes transversais baso-apicais seqüenciais e, após digitalização dos mesmos, por meio de método computadorizado, foram obtidas medidas perimetrais e espessura das paredes. Empregando-se o mesmo método, mensurou-se o perímetro do anel mitral. Foram criados índices de proporção porcentual entre os perímetros dos segmentos provenientes dos cortes do VE, comparando-os intergrupos. Nos dilatados os perímetros segmentares mensurados foram comparados com os perímetros esperados se considerássemos a câmara ventricular como uma esfera perfeita. Realizou-se a análise estatística dessas medidas e índices. RESULTADOS: O perímetro do anel mitral teve o seguinte resultado: somente o grupo CMDIsq teve média significativamente maior que o grupo NORMAL e houve baixo coeficiente de correlação com os perímetros ventriculares segmentares nos corações dilatados. Distância do sulco atrioventricular até o ápice do VE: CMDId = CMDIsq > NORMAL. Perímetros segmentares ventriculares basais (PerB), equatoriais (PerE) e apicais (PerA): grupo NORMAL-> PerE = PerB > PerA; grupos CMDId e CMDIsq- > PerE > PerB > PerA, sendo que o grupo CMDId teve essas 3 medidas maiores que o grupo CMDIsq e ambos tiveram essas 3 medidas maiores que o grupo NORMAL. Nos 3 grupos as medidas de espessura das paredes ventriculares foram iguais estatisticamente. O índice de proporção perimetral PerB/PerE foi igual nos 3 grupos, enquanto o índice PerA/PerE foi igual entre os corações dilatados, mas em ambos foi menor que no grupo NORMAL. Todos perímetros segmentares ventriculares dos corações dilatados foram menores do que os calculados segundo a fórmula da esfera. CONCLUSÕES: 1) O anel atrioventricular esquerdo dilata-se na CMDIsq, sendo essa alteração independente da dilatação dos três segmentos do VE; 2) Os corações com CMDId e CMDIsq desenvolvem uma similar dilatação longitudinal do VE; 3) Ocorre uma dilatação trans versal do VE nessas afecções, sendo essa maior nos corações com CMDId; 4) A espessura das paredes ventriculares esquerdas dos corações com CMDIsq ou CMDId não se altera quando comparada aos corações normais; 5) A dilatação transversal da câmara ventricular esquerda nos corações com CMD não se dá de forma proporcional ao longo do seu eixo longitudinal, sendo mais acentuada nas regiões basal e equatorial; 6) A câmara ventricular esquerda nos corações com CMD de origem isquêmica ou idiopática não apresenta formato esférico. / BACKGROUND: Anatomic knowledge is the cornerstone for the development of surgical and diagnostic image techniques and for understanding pathological entities. Understanding cardiac anatomy is essential for understanding cardiac remodeling in both ischemic and idiopathic dilated cardiomyopathies. Dysfunction in the physiological relationship between the morphology of left ventricle and its mitral ring plays an important role in the cardiac insufficiency etiopathogenesis. OBJECTIVES: 1) To compare morphology of left ventricle and its mitral ring among normal, ischemic and idiopathic dilated cardiomyophatic anatomic specimens; 2) To compare intra specimen ventricular segmental perimeters relationships between normal and dilated specimens; 3) To verify the presence of the spheroid shape of left ventricular chamber in dilated specimens. METHODS: It was analyzed 43 specimens of human hearts, classified in three groups: normal (n=10), dilated due to ischemic (n=15) or idiopathic cardiomyopathies (n=18). Several lengths were measured: the length from the posterior atrioventricular sulcus to the ventricular apex in the intact specimen; followed by three sequential transversal ventricular slicing in the basal, equatorial and apical level. Digital pictures were taken from these slices, in order to be analyzed in a computer assisted fashion. Internal perimeter and ventricular walls width of each slice were measured, as well the mitral ring perimeter. The three intra group perimeters were compared and correlated between themselves. Basal, equatorial and apical perimeter of each group was compared to their correspondent pairs inter groups. Regarding intra group relationships, for a given group, each slice perimeter was measured and considered as a percentage of the equatorial slice (index). This percentage was compared inter groups. Three perimeters were evaluated in both dilated groups, each one was compared to its expected value when considering left ventricular chamber as a perfect sphere (hypothesis). Measurements and index statistical analysis was performed. RESULTS: Mitral ring perimeter was longer than the NORMAL group only in ischemic group. There was a low correlation coefficient between mitral ring perimeter and ventricular segmental perimeters in both dilated groups. Longitudinal length from the left atrioventricular sulcus until the apex was similar in dilated specimens and higher compared to the normal group. Regarding sequential perimeters of ventricular slices in the normal specimens, the equatorial perimeter was as long as the basal ones, but both of them longer than the apical one. In the other hand, for dilated specimens, equatorial diameter was the longest one and apic al the smallest one. Comparing ventricular slices perimeters between dilated groups, all the perimeters lengths were longer in the idiopathic group than in the ischemic one. All the ventricular slices perimeters were longer for both dilated groups than for the normal group. There was no difference of ventricular wall width between groups. The proposed index of proportional perimeter: considering the proportion between basal and equatorial perimeter, there was no difference between any groups; but considering the proportion between apical and equatorial perimeter, dilated specimens displayed a lower index when compared to normal specimens. All the observed ventricular slice perimeters were smaller than the hypothetical (sphere) expected ones in both dilated groups. CONCLUSIONS: 1) Left atrioventricular ring dilatation occurs in ischemic dilated cardiomyopathy and it is independent of the dilatation of segments (apical, basal and equatorial) ventricular; 2) Longitudinal left ventricular dilatation is similar between dilated groups; 3) A transversal ventricular chamber dilatation was observed in dilated diseases and it is greater in the idiopathic disease; 4) The left ventricular wall widths in both dilated cardiomyopathies were similar to normal hearts; 5) Transversal dilatation of left ventricular chamber in both dilated cardiomyopathies is not proporcional along their longitudinal axis because it is more accentuated in equatorial and basal regions; 6) Left ventricular chamber in both dilated cardiomyopathies does not keep spherical shape.

INTRODUÇÃO: O conhecimento anatômico desempenha importante papel no desenvolvimento de técnicas diagnósticas e cirúrgicas. Com esse objetivo, na área cardiológica, se mostra fundamental para o entendimento do processo de remodelamento cardíaco que acompanha as cardiomiopatias dilatadas (CMD) tanto isquêmicas (CMDIsq) como idiopáticas (CMDId), de modo particular do ventrículo esquerdo (VE) e sua correlação com alterações do anel atrioventricular esquerdo, levando a graus variáveis de insuficiência cardíaca (IC). OBJETIVOS: Os objetivos desta pesquisa são: 1) Obter medidas do anel atrioventricular esquerdo (mitral) e do ventrículo esquerdo em corações normais, com CMDIsq ou CMDId, comparando-as entre si; 2) Analisar a proporcionalidade entre segmentos da câmara ventricular esquerda dos corações com CMDIsq ou CMDId em relação ao normal; 3) Determinar a esfericidade ou não da câmara ventricular esquerda nos corações com CMDIsq ou CMDId. MÉTODO: Foram analisados 43 corações humanos, divididos em três grupos: NORMAL (n=10), CMDIsq (n=15) e CMDId (n=18). De posse da medida da distância do sulco atrioventricular posterior até o ápice do VE, foram realizados cortes transversais baso-apicais seqüenciais e, após digitalização dos mesmos, por meio de método computadorizado, foram obtidas medidas perimetrais e espessura das paredes. Empregando-se o mesmo método, mensurou-se o perímetro do anel mitral. Foram criados índices de proporção porcentual entre os perímetros dos segmentos provenientes dos cortes do VE, comparando-os intergrupos. Nos dilatados os perímetros segmentares mensurados foram comparados com os perímetros esperados se considerássemos a câmara ventricular como uma esfera perfeita. Realizou-se a análise estatística dessas medidas e índices. RESULTADOS: O perímetro do anel mitral teve o seguinte resultado: somente o grupo CMDIsq teve média significativamente maior que o grupo NORMAL e houve baixo coeficiente de correlação com os perímetros ventriculares segmentares nos corações dilatados. Distância do sulco atrioventricular até o ápice do VE: CMDId = CMDIsq > NORMAL. Perímetros segmentares ventriculares basais (PerB), equatoriais (PerE) e apicais (PerA): grupo NORMAL-> PerE = PerB > PerA; grupos CMDId e CMDIsq- > PerE > PerB > PerA, sendo que o grupo CMDId teve essas 3 medidas maiores que o grupo CMDIsq e ambos tiveram essas 3 medidas maiores que o grupo NORMAL. Nos 3 grupos as medidas de espessura das paredes ventriculares foram iguais estatisticamente. O índice de proporção perimetral PerB/PerE foi igual nos 3 grupos, enquanto o índice PerA/PerE foi igual entre os corações dilatados, mas em ambos foi menor que no grupo NORMAL. Todos perímetros segmentares ventriculares dos corações dilatados foram menores do que os calculados segundo a fórmula da esfera. CONCLUSÕES: 1) O anel atrioventricular esquerdo dilata-se na CMDIsq, sendo essa alteração independente da dilatação dos três segmentos do VE; 2) Os corações com CMDId e CMDIsq desenvolvem uma similar dilatação longitudinal do VE; 3) Ocorre uma dilatação trans versal do VE nessas afecções, sendo essa maior nos corações com CMDId; 4) A espessura das paredes ventriculares esquerdas dos corações com CMDIsq ou CMDId não se altera quando comparada aos corações normais; 5) A dilatação transversal da câmara ventricular esquerda nos corações com CMD não se dá de forma proporcional ao longo do seu eixo longitudinal, sendo mais acentuada nas regiões basal e equatorial; 6) A câmara ventricular esquerda nos corações com CMD de origem isquêmica ou idiopática não apresenta formato esférico. / BACKGROUND: Anatomic knowledge is the cornerstone for the development of surgical and diagnostic image techniques and for understanding pathological entities. Understanding cardiac anatomy is essential for understanding cardiac remodeling in both ischemic and idiopathic dilated cardiomyopathies. Dysfunction in the physiological relationship between the morphology of left ventricle and its mitral ring plays an important role in the cardiac insufficiency etiopathogenesis. OBJECTIVES: 1) To compare morphology of left ventricle and its mitral ring among normal, ischemic and idiopathic dilated cardiomyophatic anatomic specimens; 2) To compare intra specimen ventricular segmental perimeters relationships between normal and dilated specimens; 3) To verify the presence of the spheroid shape of left ventricular chamber in dilated specimens. METHODS: It was analyzed 43 specimens of human hearts, classified in three groups: normal (n=10), dilated due to ischemic (n=15) or idiopathic cardiomyopathies (n=18). Several lengths were measured: the length from the posterior atrioventricular sulcus to the ventricular apex in the intact specimen; followed by three sequential transversal ventricular slicing in the basal, equatorial and apical level. Digital pictures were taken from these slices, in order to be analyzed in a computer assisted fashion. Internal perimeter and ventricular walls width of each slice were measured, as well the mitral ring perimeter. The three intra group perimeters were compared and correlated between themselves. Basal, equatorial and apical perimeter of each group was compared to their correspondent pairs inter groups. Regarding intra group relationships, for a given group, each slice perimeter was measured and considered as a percentage of the equatorial slice (index). This percentage was compared inter groups. Three perimeters were evaluated in both dilated groups, each one was compared to its expected value when considering left ventricular chamber as a perfect sphere (hypothesis). Measurements and index statistical analysis was performed. RESULTS: Mitral ring perimeter was longer than the NORMAL group only in ischemic group. There was a low correlation coefficient between mitral ring perimeter and ventricular segmental perimeters in both dilated groups. Longitudinal length from the left atrioventricular sulcus until the apex was similar in dilated specimens and higher compared to the normal group. Regarding sequential perimeters of ventricular slices in the normal specimens, the equatorial perimeter was as long as the basal ones, but both of them longer than the apical one. In the other hand, for dilated specimens, equatorial diameter was the longest one and apic al the smallest one. Comparing ventricular slices perimeters between dilated groups, all the perimeters lengths were longer in the idiopathic group than in the ischemic one. All the ventricular slices perimeters were longer for both dilated groups than for the normal group. There was no difference of ventricular wall width between groups. The proposed index of proportional perimeter: considering the proportion between basal and equatorial perimeter, there was no difference between any groups; but considering the proportion between apical and equatorial perimeter, dilated specimens displayed a lower index when compared to normal specimens. All the observed ventricular slice perimeters were smaller than the hypothetical (sphere) expected ones in both dilated groups. CONCLUSIONS: 1) Left atrioventricular ring dilatation occurs in ischemic dilated cardiomyopathy and it is independent of the dilatation of segments (apical, basal and equatorial) ventricular; 2) Longitudinal left ventricular dilatation is similar between dilated groups; 3) A transversal ventricular chamber dilatation was observed in dilated diseases and it is greater in the idiopathic disease; 4) The left ventricular wall widths in both dilated cardiomyopathies were similar to normal hearts; 5) Transversal dilatation of left ventricular chamber in both dilated cardiomyopathies is not proporcional along their longitudinal axis because it is more accentuated in equatorial and basal regions; 6) Left ventricular chamber in both dilated cardiomyopathies does not keep spherical shape.

Ventricular premature beats are ectopic changes in the ECG signal. Detection of ventricular extrasystoles on 12leads ECG was created in MATLAB. At first my work involves whether the ventricular premature beats comes from the right or the left ventricle. Another algorithm evaluates the incidence outflow tract of the chamber. If the previous algorithm shows signs of indecision, another algorithm is used for detection of ventricular extrasystoles at another location in the left ventricle. The last step is to narrow the area of detection which makes it easier to find the place of origin.

Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: This dissertation considers automatic segmentation of the left cardiac ventricle in short axis magnetic resonance images. The presence of papillary muscles near the endocardium border makes simple threshold based segmentation difficult. The endo- and epicardium are modelled as two series of radii which are inter-related using features describing shape and motion. Image features are derived from edge information from human annotated images. The features are combined within a Conditional Random Field (CRF) – a discriminatively trained probabilistic model. Loopy belief propagation is used to infer segmentations when an unsegmented video sequence is given. Powell’s method is applied to find CRF parameters by minimising the difference between ground truth annotations and the inferred contours. We also describe how the endocardium centre points are calculated from a single human-provided centre point in the first frame, through minimisation of frame alignment error. We present and analyse the results of segmentation. The algorithm exhibits robustness against inclusion of the papillary muscles by integrating shape and motion information. Possible future improvements are identified. / AFRIKAANSE OPSOMMING: Hierdie proefskrif bespreek die outomatiese segmentasie van die linkerhartkamer in kortas snit magnetiese resonansie beelde. Die teenwoordigheid van die papillêre spiere naby die endokardium grens maak eenvoudige drumpel gebaseerde segmentering moeilik. Die endo- en epikardium word gemodelleer as twee reekse van die radiusse wat beperk word deur eienskappe wat vorm en beweging beskryf. Beeld eienskappe word afgelei van die rand inligting van mens-geannoteerde beelde. Die funksies word gekombineer binne ’n CRF (Conditional Random Field) – ’n diskriminatief afgerigte waarskynlikheidsverdeling. “Loopy belief propagation” word gebruik om segmentasies af te lei wanneer ’n ongesegmenteerde video verskaf word. Powell se metode word toegepas om CRF parameters te vind deur die minimering van die verskil tussen mens geannoteerde segmentasies en die afgeleide kontoere. Ons beskryf ook hoe die endokardium se middelpunte bereken word vanaf ’n enkele mens-verskafte middelpunt in die eerste raam, deur die minimering van ’n raambelyningsfout. Ons analiseer die resultate van segmentering. Die algoritme vertoon robuustheid teen die insluiting van die papillêre spiere deur die integrasie van inligting oor die vorm en die beweging. Moontlike toekomstige verbeterings word geïdentifiseer.

Contexte : Le tissu biologique mou présente une organisation structurelle extrêmement complexe et est le siège de nombreux phénomènes d'échanges. De nombreuses applications s'étendant du diagnostic clinique à l'ingénierie tissulaire nécessitent la connaissance du comportement mécanique du tissu. A cette fin, de nombreuses approches plus ou moins satisfaisantes sont développées. Elles s'efforcent toutes de tenir compte de manière plus ou moins systématique de la microstructure du milieu. La considération du tissu biologique comme un milieu micromorphe donne des résultats probants dans sa particularisation au milieu micropolaire appliquée au tissu osseux. Il est donc fort probable que des résultats du genre soient obtenus pour d'autres tissus. Notre travail était orienté vers le tissu cardiaque et la problématique de l'infarctus ischémique. Dans ce contexte, il nous a semblé que la particularisation de comportement la mieux adaptée est celle d'un milieu à microdilatation. Travail réalisé : Le travail réalisé dans le cadre de cette thèse est essentiellement numérique. Il a pour objectif de mettre en lumière les particularités de la réponse à une sollicitation extérieure d'un échantillon de milieu à microdilatation. Cette étape est essentielle pour l'analyse future des résultats d'expériences qui seront menées. Il a également pour objectif d'étudier les potentialités du modèle vis-à-vis du tissu cardiaque en considérant l'infarctus ischémique et la perte associée de la capacité d'éjection de volume sanguin. Les outils numériques d'analyse de tels milieux sont en plein développement. Il nous a fallu développer notre propre outil basé sur la LPI-BEM (Local Point Interpolation - Boundary Element Method). Du fait de la similitude des équations de champs associées, la validité de la stratégie numérique mise en oeuvre est testée sur le cas d'un matériau piézoélectrique. Ce choix n'est pas innocent car, dans l'avenir la considération du milieu piézoélectrique à microdilatation permettra d'analyser le cas d'une sollicitation électrique du tissu. Les détails de cette stratégie numérique originale sont consignés dans le chapitre 2 du mémoire. Le chapitre 3 est consacré à l'analyse de la robustesse de la méthode et aux particularités de la réponse d'un milieu à microdilatation. Le quatrième chapitre est consacré à l'application au tissu cardiaque. En se limitant au cas de petites déformations, on montre que le modèle est bien adapté à la représentation du comportement du tissu cardiaque. En effet, assimilant le ventricule gauche à une structure tubulaire, la fraction d'éjection du ventricule gauche (critère clinique d'insuffisance cardiaque) est fortement diminuée en présence d'une zone infarcie. Cette dernière est modélisée comme une région à frontière diffuse où les points matériels ont perdu leur capacité de « respirer ». Ces résultats sont prometteurs. Ils encouragent à poursuivre dans cette voie en prenant en compte le caractère anisotrope du tissu et en se plaçant dans le cadre des grandes déformations / Background: A soft biological tissue is subjected to numerous exchange phenomena and has an extremely complex structural organization. The knowledge of its mechanical behavior is required in many applications ranging from clinical diagnostic to tissue engineering. To achieve this goal, more or less satisfactory approaches are developed. They all seek to take into account in a more or less systematic manner the microstructure of the medium. Assuming that the biological tissue is a particular micromorphic medium (micropolar medium) leads to good results in the case bone tissue. It is therefore likely that the results of this kind will be obtained for other tissues. Our interest is on the heart tissue and the problem of ischemic heart attack. In this context, it seemed that the most appropriate behavior particularization is that of a microdilatation medium. Work done: The work presented in this thesis is essentially numerical. It aims to highlight the features of the response of microdilatation medium to an external mechanical load. This step is essential for the analysis of the experimental results to be conducted in the future. The work also aims to investigate the potentialities of the model with respect to the heart tissue regarding heart attack and the associated loss of the ability to eject sufficient blood volume. The numerical tools for the analysis of such media are in increasing development. We had to develop our own tool based on the LPI-BEM (Local Point Interpolation - Boundary Element Method). Because of the similarity of the associated field equations, the validity of the numerical strategy is assessed in the case of a piezoelectric material. This choice is not innocent because the piezoelectric medium with microdilatation will allow analyzing the case of an electrical solicitation of the tissue. The details of this original numerical approach are given in Chapter 2 of the thesis. Chapter 3 is devoted to the analysis of the robustness of the method and to the peculiarities of the response of a microdilatation medium. The fourth chapter is devoted to the application to the cardiac tissue. By limiting the study to the case of small strains, it is shown that the model is well suited to the representation of the behavior of cardiac tissue. Indeed, considering the left ventricle as a tubular structure, the left ventricle ejection fraction (clinical criterion of the heart failure) is greatly reduced in the presence of an infarcted area. The latter is modeled as a zone with diffuse boundary where the material points have lost their ability to "breath". These results are promising and encourage further investigations in this direction by taking into account the anisotropic nature of the tissue in a geometrically nonlinear context

Heutzutage stellt der Erhalt des posterioren Halteapparates beim Mitralklappenersatz (MKE) ein Routineverfahren dar. Das Ziel dieser Studie war es festzustellen, ob der komplette Erhalt der subvalvulären Strukturen beim Mitralklappenersatz Vor- oder Nachteile hat. Es wird über die Erfahrungen mit 48 Patienten berichtet. Die Gruppe MKEh bestand aus 15 Patienten, bei denen beim MKE der komplette subvalvuläre Halteapparat erhalten wurde. Die Gruppe MKEo, bei denen beim MKE nur der posteriore Halteapparat erhalten wurde, bestand aus 9 Patienten. Die dritte Gruppe (MKR) enthielt 12 Patienten, bei denen die Mitralklappe rekonstruiert worden war und die vierte Gruppe (KG) bestand aus 12 Herzgesunden ohne Klappendefekt, die die Kontrollgruppe darstellte. Die Patienten wurden einer ausführlichen Befragung unterzogen sowie prä- und postoperativ echokardiographisch untersucht und die Ergebnisse verglichen. Bezüglich der Ergebnisse der Befragungen und der präoperativen echokardiographischen Ergebnisse fanden sich bei den drei operierten Gruppen (MKEh, MKEo, MKR) keine signifikanten Unterschiede. Demgegenüber wurden postoperative Unterschiede festgestellt: Bei den Patienten mit MKE, bei denen aber der vordere Halteapparat nicht konserviert wurde (MKEo), fand sich eine signifikant geringere systolische Verkürzung zwischen dem Apex und der Mitralklappenbasis (6,5 mm - 15 mm), die systolische Kontraktion begann bei diesen Patienten außerdem nicht im Bereich des Apex und der posteriore Papillarmuskel führte in diesen Fällen keine aktive Kontraktion aus. Es konnte somit die Schlußfolgerung gezogen werden, daß der komplette subvalvuläre Apparat notwendig ist, damit der linke Ventrikel eine physiologische Kontraktion durchführen kann. Er sollte somit immer beim Mitralklappenersatz komplett erhalten werden, sofern die Papillarmuskeln und die Chorden intakt sind und keine Mitralklappenrekonstruktion durchgeführt werden kann. / Today preservation of the chordal attachment to the posterior leaflet in mitral valve replacement (MVR) is a routine, universally accepted procedure. The aim of this study was to show the advantages and disadvantages of the preservation of the entire subvalvular structures. Our institution's experience with 48 patients in four groups is reported. The MKEh group consists of 15 patients who underwent MVR with preservation of the entire subvalvular structures. The MKEo group, treated with MVR and preservation of the posterior subvalvular structures only, consists of 9 patients. The third group (MVR) consists of 12 patients with mitral valve reconstruction and group 4 (CG) of 12 healthy individuals without heart valve dysfunction, as a control group. The patients were assessed by questioning and echocardiography pre- and postoperatively and the results compared. In questioning and in the preoperative echocardiography results no differences were seen between the three surgical groups (MKEh, MKEo, MKR). However, considerable differences were present in the postoperative echocardiography results: in patients without preservation of the anterior subvalvular structures (MKEo group) the shortening between the apex and the mitral valve basis is significantly less (6.5 mm - 15 mm), the systolic contraction does not begin at the apex and the posterior papillary muscle does not actively contract. It is concluded that preservation of the entire subvalvular structures is important to ensure physiological contraction of the left ventricle. They should be preserved in all mitral valve replacement operations when the papillary muscles und chordae are intact and mitral valve reconstruction cannot be performed.

L'imagerie par résonance magnétique (IRM) est un outil remarquable pour le diagnostic clinique, aussi bien pour l'imagerie cérébrale que pour l'imagerie cardiaque et abdominale. En IRM cardiaque, deux problèmes sont récurrents : la non reproductibilité des cycles cardiaques et le mouvement respiratoire. L'IRM cardiaque morphologique est généralement faite avec une séquence composée d'une préparation longue, visant à annuler le signal du sang pour accentuer le contraste au niveau du myocarde, et de l?acquisition à proprement parler. Ces acquisitions sont généralement faites en mésodiastole (phase de relaxation passive du coeur) ce qui permet de satisfaire les contraintes liées à l'annulation du sang et d'éviter les problèmes liés aux non reproductibilités des cycles cardiaques car la mésodiastole est longue. Il est donc difficile de satisfaire les contraintes liées à l?annulation du sang pour faire les acquisitions en télésystole (phase où le coeur est contracté) à cause des non reproductibilités cardiaques car la télésystole est courte. Afin de passer outre ces limitations et de pouvoir acquérir ces mêmes images morphologiques en télésystole, nous proposons une nouvelle méthode adaptative qui permet à la fois de placer la fenêtre d'acquisition de manière optimale et de satisfaire les contraintes liées à l'annulation du sang. Une application de cette méthode a également été mise en place pour estimer et comparer les temps de relaxation transversale (T2) entre télésystole et mésodiastole. Pour la gestion prospective du mouvement respiratoire, le point crucial est d'estimer les mouvements en temps réel en perturbant au minimum les signaux de résonance magnétique. Pour ce faire nous proposons une méthode basée sur l'estimation paramétrique des mouvements en temps réel à partir des signaux physiologiques disponibles (ceintures respiratoires et ECG). Cette méthode a été testée et les résultats montrent son intérêt et sa fiabilité par rapport aux erreurs faites au niveau du mouvement. Une méthode de reconstruction incluant les mouvements a également été utilisée pendant ces travaux afin de faire de l'imagerie en télésystole en respiration libre et d'utiliser d'autres types de capteurs respiratoires comme certains signaux de résonance magnétique. Ainsi pendant ces travaux, des méthodes adaptatives ont été mises en place afin de mieux gérer le mouvement et de prendre en compte les spécificités de chaque patient. Ces travaux ouvrent la voie de l'imagerie par résonance magnétique adaptative pleinement fonctionnelle dans un contexte clinique / Magnetic resonance imaging (MRI) is a valuable tool for the clinical diagnosis for brain imaging as well as cardiac and abdominal imaging. In cardiac MRI, there are two challenging issues: the non reproducibility of cardiac cycles and respiratory motion. Morphological cardiac MRI is generally performed with a pulse sequence composed of a long preparation, to cancel the blood signal and thus enhance the contrast of the myocardium, and the acquisition itself. These acquisitions are performed during the mid-diastolic rest (relaxation period of the heart) to satisfy constraints to cancel the blood signal and to avoid problems linked to the cardiac non reproducibility because the mid-diastolic rest is long. Consequently, to acquire images in end-systolic rest (when the heart is fully contracted) while taking into account constraints to cancel the blood signal is not straight forward due to cardiac non reproducibility because the end-systolic rest is short. To overcome these limitations and to acquire images in end-systolic rest, a new adaptive method is introduced that allows to optimally placing acquisition windows while taking constraint for the cancellation of the blood signal into account. This method was applied to measure and compare transverse relaxation time (T2) between end-systolic and mid-diastolic rests. For prospective respiratory motion correction, the crucial point is to estimate motion in real-time without perturbing MR signal used for imaging. In order to solve this issue, a new method is introduced aiming at estimating motion parameters in real-time based on physiological signals such as respiratory bellows and ECG. This method is evaluated and results show its interest and its reliability regarding motion estimation errors. A reconstructions algorithm is also used in order to perform cardiac imaging during the end-systolic rest in free breathing and to use different kind of respiratory motion sensors such as MR signals. Hence, during this research work, several adaptive method were developed to get a better management of motion and to take into account specificity of each patient. These works open the way of fully functional adaptive magnetic resonance imaging in a clinical situation

INTRODUÇÂO: A hipertensão arterial sistêmica (HAS) é uma condição clínica com alta prevalência, sendo considerada como o principal fator de risco modificável para o desenvolvimento de insuficiência cardíaca (IC). Dentre os mecanismos relacionados à progressão da HAS para a IC, a hiperatividade simpática e a disfunção endotelial devem ser consideradas. OBJETIVO: Avaliar a modulação do sistema nervoso autônomo (central e periférico), e a função endotelial em pacientes hipertensos com diferentes graus de disfunção diastólica (DD) do ventrículo esquerdo (VE). CASUÍSTICA E MÉTODO: Quarenta e cinco pacientes com HAS, sem outras co-morbidades foram submetidos ao exame de ecoDopplercardiograma tecidual, e foram alocados em três grupos: (GHT) sem alteração funcional ou estrutural cardíacas (n=15, 7 homens, 48±2 anos, IMC 28±1 Kg/m2), (GDD-ar) com diagnóstico prévio de IC diastólica e com DD padrão alteração de relaxamento do VE (n=15, 7 homens, 53±2 anos, IMC 29±1 Kg/m2) e (GDD-pr) com diagnóstico prévio de IC diastólica com padrão pseudonormal ou restritivo de DD do VE (n=15, 9 homens, 51±2 anos, IMC 27±1 Kg/m2). Voluntários saudáveis normotensos (n=14, grupo GNT) pareados para idade, sexo e IMC também foram avaliados. Curvas de pressão arterial (PA) foram registradas de modo contínuo e não invasivo (Finometer®) durante 15 minutos em repouso, na posição supina. Simultaneamente, a atividade nervosa simpática muscular (ANSM) foi registrada por meio da técnica de microneurografia. A variabilidade da freqüência cardíaca (VFC) e da pressão arterial sistólica (VPAS) foi estimada pelo método FFT. Em um segundo momento foi realizada a avaliação da função endotelial, por meio de ultrassonografia da artéria braquial associada à manobra de hiperemia reativa e após administração de trinitrato sublingual. As análises estatísticas foram realizadas pelo teste exato de Fisher e ANOVA, os resultados expressos em média ± erro padrão ou em mediana (valores mínimos e máximos). RESULTADOS: Não houve diferenças de gênero, idade e IMC entre os grupos, como também no uso das diferentes classes de drogas anti-hipertensivas entre os hipertensos. Os parâmetros estruturais cardíacos foram semelhante entre os grupos, com exceção da massa de VE do grupo GDD-pr [98 (66-162) g/m2] foi maior, p<0,05, quando comparada ao grupo GNT [85 (56-95) g/m2]. A PA sistólica (PAS) não foi diferente entre GHT, GDD-ar e GDD-pr [(138 (110-149), 133 (104-190) e 148 (118-171) mmHg, respectivamente]. Os grupos GDD-ar e GDD-pr apresentaram PAS maiores, p<0,05,quando comparados ao grupo GNT [121(108-133) mmHg]. A PA diastólica foi semelhante entre os grupos. Os grupos mostraram semelhantes valores para a modulação autonômica cardíaca avaliada pela VFC. A modulação simpática periférica representada pelo componente LF PAS da VPAS (mmHg2) foi aumentada nos grupos GDD-ar (12,2±1,3) e GDD-pr (11,7±1,2) quando comparados ao grupo GNT (6,7±0,6), p<0,05, mas não quando comparada ao grupo GHT (9,3±1,1). O prejuízo baroreflexo (índice alfa LF, ms/mmHg) foi observado nos grupos GDD-ar (4,6±0,6) e GDD-pr (5,07±0,7) quando comparados ao grupo GNT (8,2±1), p<0,05, mas não quando comparados ao grupo GHT (6,05±0,5). ANSM (espículas/min) foi maior significativamente nos grupos GDD-ar (33±1) e GDD-pr (32±1) quando comparada aos grupos GHT (26±1) e GNT (15±1) p<0,05. Ainda, o grupo GHT apresentou aumento da ANSM quando comparado ao grupo GNT, p<0,05. Os grupo GDD-ar e GDD-pr apresentaram valores semelhantes de ANSM. Com relação à avaliação da função endotelial, os grupos hipertensos apresentaram menor dilatação dependente do endotélio, sendo que somente no grupo GDD-ar [0,67 (0,0-8,7)%] houve significância estatística quando comparado ao GNT [6,3 (2,6-8,2)%]. Na avaliação da vasodilatação independente do endotélio os grupos apresentaram respostas semelhantes. CONCLUSÃO: A presença de disfunção diastólica, em qualquer grau, está associada à maior ANSM e modulação simpática periférica (LF PAS) e a menor sensibilidade do baroreflexo. A modulação simpática cardíaca não apresentou diferença entre os grupos em repouso. Outros estudos são necessários para esclarecer a relação entre causa - efeito de tais achados / INTRODUTION: The hypertension (HP) is a clinical condition with high prevalence, considered as a main modifiable risk factor for developing heart failure (HF). Among the mechanism related to the progression for HP to the HF, the sympathetic hyperactivity and endothelial dysfunction should be considered. OBJECTIVE: Evaluate the autonomic nervous system modulation (central and peripheral), and endothelial function in hypertensive patients with different pattern of diastolic dysfunction (DD) of the left ventricle (LV). METHOD: Forty-five hypertensive patients without comorbities were submitted to tissue Doppler echocardiography and allocated into three groups: (GHT) without cardiac functional or structural abnormalities (n=15, 7 men, 48±2 years, BMI 28±1 Kg/m2); (GDD-ar) with prior diastolic HF and impaired relaxation pattern of DD of LV (n=15, 7 men, 53±2 years, BMI 29±1 Kg/m2), and (GDD-pr) with prior diastolic HF and pseudonormal and restrictive patterns of DD of LV (n=15, 9 men, 51±2 years, BMI 27±1 Kg/m2). Normotensive healthy volunteers matched for age, sex and body mass index were also evaluated. Curves of blood pressure (BP) were recorded non-invasively and continuously (Finometer®) for 15 minutes at rest in the supine position. Simultaneously, muscle nerve sympathetic activity (MNSA) was recorded by microneurography technique. The heart rate and systolic blood pressure variability (HRV and SPBV) was estimated by FFT method. Afterwards, an evaluation of endothelial function through brachial artery ultrasound maneuver associated with reactive hyperemia and after sublingual administration of trinitrate was conducted. Statistical analysis was performed by Fishers exact test and ANOVA, the results are expressed as mean±standard deviation or median (minimum and maximum values). RESULTS: There were no differences in gender, age and BMI between the groups, as well as in the use of different classes of antihypertensive drugs among hypertensive patients. Cardiac structural parameters were similar between groups, except for LV mass in GDD-pr group [98 (66-162) g/m2] which was higher, p<0.05, when compared to the GNT group [85 (56-95) g/m2]. The systolic blood pressure (SBP) was similar between GHT, GDD-ar and GDD-pr groups [(138 (110-149), 133 (104-190) e 148 (118-171) mmHg, respectively]. The GDD-ar and GDD-pr groups had higher SBP, p<0.05, when compared to GNT group [121(108-133) mmHg]. The diastolic BP was similar between groups. The groups showed similar values for cardiac autonomic modulation assessed by HRV. The peripheral sympathetic modulation represented by the LF component of SBP (SBPV, mmHg2) was increased in GDD-ar group (12,2±1,3) and GDD-pr group (11,7±1,2) compared to the GNT group (6,7±0,6), p<0.05, but not when compared to GHT group (9,3±1,1). The impairment of the baroreflex (LF alpha índex, ms/mmHg) was observed in the GDD-ar (4,6±0,6) e GDD-pr (5,07±0,7) groups compared to the GNT group (8,2±1), p<0.05, but not when compared to GHT group (6,05±0,5). MNSA (burst/min) was significantly higher in GDD-ar (33±1) e GDD-pr (32±1) groups compared to GHT group (26±1) and GNT group (15±1) p<0.05. Also the GHT group showed increased MNSA when compared to GNT group, p<0.05. The GDD-ar and GDD-pr groups showed similar values of MNSA. Regarding the assessment of endothelial function, hypertensive groups had lower endothelium-dependent dilatation, but only in GDD-ar group [0,67 (0,0-8,7)%] was statistically significant when compared to GNT group [6,3 (2,6-8,2)%]. In the evaluation of endothelium-independent vasodilatation all groups showed similar responses. CONCLUSION: The presence of diastolic dysfunction of any pattern is associated with higher MNSA and peripheral sympathetic modulation (LF SBP) and lower sensitivity of the baroreflex. Cardiac sympathetic modulation did not differ between groups at rest. Further studies are needed to clarify the relationship between cause-effect of such findings