Literatura académica sobre el tema "Left atrial strain"
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Artículos de revistas sobre el tema "Left atrial strain"
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Buggey, Jonathan y Brian D. Hoit. "Left atrial strain". Current Opinion in Cardiology 33, n.º 5 (septiembre de 2018): 479–85. http://dx.doi.org/10.1097/hco.0000000000000537.
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Litwin, Sheldon E. "Left Atrial Strain". JACC: Cardiovascular Imaging 13, n.º 10 (octubre de 2020): 2114–16. http://dx.doi.org/10.1016/j.jcmg.2020.07.037.
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Marwick, Thomas H. y Y. Chandrashekhar. "Left Atrial Strain". JACC: Cardiovascular Imaging 13, n.º 10 (octubre de 2020): 2278–79. http://dx.doi.org/10.1016/j.jcmg.2020.09.001.
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Cho, Goo-Yeong y In-Chang Hwang. "Left Atrial Strain Measurement". JACC: Cardiovascular Imaging 13, n.º 11 (noviembre de 2020): 2327–29. http://dx.doi.org/10.1016/j.jcmg.2020.05.014.
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Negishi, Kazuaki. "Incremental Diagnostic Value of Left Atrial Strain Over Left Atrial Volume". JACC: Cardiovascular Imaging 11, n.º 10 (octubre de 2018): 1416–18. http://dx.doi.org/10.1016/j.jcmg.2017.10.011.
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Tsujiuchi, Miki, Mio Ebato, Ryohei Fujimoto, Sakura Nagumo, Takuya Mizukami, Hideyuki Maezawa y Hiroshi Suzuki. "Left Atrial Circumferential Strain is More Sensitive Index of Left Atrial Pressure Than Longitudinal Strain". Journal of Cardiac Failure 22, n.º 9 (septiembre de 2016): S175. http://dx.doi.org/10.1016/j.cardfail.2016.07.123.
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Henein, Michael, Erik Tossavainen, Stefan Söderberg, Christer Grönlund, Manuel Gonzalez y Per Lindqvist. "Left atrial strain rate estimates PCWP". International Cardiovascular Forum Journal 1, n.º 1 (29 de marzo de 2015): 25. http://dx.doi.org/10.17987/icfj.v1i1.11.
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<p><span>Objective: </span>Raised left atrial (LA) pressure is a common pathway for many pathologies and is known for its complications. It has a direct effect on LA cavity size and potentially also its function. We hypothesized that raised LA pressure, as shown by pulmonary capillary wedge pressure (PCWP), correlates with severity of global LA deformation abnormalities during atrial systole (LASRa).</p><p>Design and Patients: We prospectively studied 46 consecutive patients, mean age 61 +/-13 years, 17 males, of various etiologies who underwent right heart catheterization and simultaneous Doppler echocardiography using spectral, tissue Doppler and speckle tracking echocardiography techniques for assessing LA structure and function.</p><p><span>Results: </span>PCWP correlated with direct measurements of LA structure and function: LA volume (r= 0.43, p<0.01) and LASRa (r=0.79, p<0.001). PCWP correlated also with other indirect measures of LA pressure such as E/A (r=0.65, p<0.001), E wave deceleration time (r=0.54, p<0.001), E/e’ (r=0.49, p<0.001) and LA systolic filling fraction (r=0.52, p<0.001). However, LASRa together with LA systolic filling fraction, had the highest areas under the curve (0.83 and 0.87, respectively) for identifying patients with PCWP > 15 mmHg.</p><p><span>Conclusion: </span>PCWP correlates with LA deformation rate during atrial systole and to a higher extent than conventional Doppler measures of raised LA pressures. These findings should have significant clinical implications in correctly identifying breathless patients due to raised LA pressure.</p><p> </p>
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To, Andrew C. Y. y Allan L. Klein. "Left Atrial Function: Doppler and Strain". Current Cardiovascular Imaging Reports 3, n.º 5 (11 de agosto de 2010): 276–85. http://dx.doi.org/10.1007/s12410-010-9041-9.
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Arslan, Sakir, Ziya Simsek, Fuat Gundogdu, Enbiya Aksakal, Mehmet Emin Kalkan, Yekta Gurlertop, Mustafa Kemal Erol y Sule Karakelleoglu. "Can Left Atrial Strain and Strain Rate Imaging Be Used to Assess Left Atrial Appendage Function". Cardiology 121, n.º 4 (2012): 255–60. http://dx.doi.org/10.1159/000337291.
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Russell, Ashley K., Gursukhmandeep Sidhu, Mary Jenkins, Wm Long, Mark Cassidy y Nassir Marrouche. "PROGNOSTIC VALUE OF LEFT ATRIAL STRAIN AND RECURRENCE OF ATRIAL FIBRILLATION POST-ABLATION: A META ANALYSIS OF LEFT ATRIAL STRAIN AND LEFT ATRIAL VOLUME INDEX". Journal of the American College of Cardiology 77, n.º 18 (mayo de 2021): 1331. http://dx.doi.org/10.1016/s0735-1097(21)02689-9.
Texto completoTesis sobre el tema "Left atrial strain"
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Labombarda, Fabien. "Μyοcardial mechanics and cardiac remοdeling in cοngenital left ventricular οutflοw οbstructiοn Increasing Prevalence of Atrial Fibrillation and Permanent Atrial Arrhythmias in Congenital Heart Disease Left atrial stiffness in corrected congenital left ventricular outflow obstruction Impaired left atrial function in adults and adolescents with corrected aortic coarctation Right Ventricular Strain Impairment in Adults and Adolescents with Repaired Aortic Coarctation". Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC401.
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L’objectif de cette thèse est d'analyser en échocardiographie le remodelage et la fonction cardiaque après correction optimale d’un obstacle congénital du cœur gauche et d’identifier de potentiels marqueurs de risque de survenue de fibrillation atriale. Le premier axe de ce travail est une étude prospective multicentrique qui présente le profil évolutif des arythmies atriales chez les adultes porteurs d’une cardiopathie congénitale. Cette étude démontre l’importance de la fibrillation atriale qui devient l’arythmie prédominante après l’âge de 50 ans chez ces patients. Le deuxième axe de travail s’intéresse à la rigidité atriale, un indice échocardiographique corrélé à la présence de fibrose et à la survenue de fibrillation atriale. Nous avons montré que la rigidité atriale est anormale malgré la correction optimale d’un obstacle congénital du cœur gauche, en particulier chez les patients opérés d’une coarctation aortique. Les troisième et quatrième axe de recherche ont exploré spécifiquement le remodelage et la fonction cardiaque après cure de coarctation. Dans la troisième étude, l’analyse en 2D strain a permis d’identifier une forte prévalence de dysfonction atriale chez des adultes et adolescents opérés d’une coarctation aortique. La fonction atriale est influencée par l’anatomie de l’arche aortique ; une relation entre la fonction atriale et la survenue d’évènements cardiovasculaires a été trouvée. Enfin, dans le dernier travail, l’analyse du cœur droit en 2D strain a permis de révéler des anomalies de la fonction ventriculaire droite après cure de coarctation. Nos résultats illustrent l’apport potentiel des nouvelles techniques d’imagerie comme le 2D strain pour identifier des patients à risque de développer une fibrillation atriale dont la prévention est un des enjeux majeurs de la cardiologie congénitale adulteThe objective of this thesis is to analyze myocardial mechanics and cardiac remodeling and function, using transthoracic echocardiography, after optimal correction of a congenital obstruction of the left ventricle and to identify potential risk markers for the occurrence of atrial fibrillation. The first focus of this work is a prospective multicenter study presenting the evolutionary pattern of atrial arrhythmias in adults with congenital heart disease. This study demonstrates the prominence of atrial fibrillation, which becomes the predominant atrial arrhythmia after the age of 50 in these patients. The second area of study focuses on left atrial stiffness, a recent echocardiographic index well correlated with the presence of atrial fibrosis and occurrence of atrial fibrillation. We demonstrate that left atrial stiffness may be abnormal despite optimal correction of a congenital left heart obstruction, especially in patients experiencing aortic coarctation and in overweight patients. The third and fourth lines of research specifically explore remodeling and cardiac function in patients whose aortic coarctation has been repaired. In the third area of research, we use two-dimensional strain analysis to detect a high prevalence of left atrial dysfunction in adults and adolescents after aortic coarctation repair. Left atrial dysfunction is influenced by the anatomy of the aortic arch; a potential relationship with cardiovascular events and left atrial function is identified. Finally, in the last area of research, we identify anomalies of the right ventricular function after coarctation repair. Our results illustrate the potential contribution of new imaging techniques such as two-dimensional strain to identify patients at risk of developing atrial fibrillation, the prevention of which is one of the current challenges in adult congenital cardiology
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Sousa, Francisco Thiago Tomaz de. "Avaliação ecocardiográfica da função do átrio esquerdo como marcadora de eventos em pacientes com insuficiência cardíaca". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/98/98131/tde-02012018-133920/.
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Introdução: O strain do átrio esquerdo (AE) permite uma análise quantitativa da função do AE. A relevância clínica desta medida é dependente da informação incremental à análise da função do ventrículo esquerdo (VE), particularmente importante em indivíduos portadores de insuficiência cardíaca (IC). O objetivo deste estudo foi avaliar o impacto prognóstico da disfunção atrial em pacientes com IC. Método: Ecocardiograma foi realizado em 217 pacientes em ritmo sinusal com IC e fração de ejeção (FE) do VE<40%. A análise do strain do AE foi avaliada por meio do speckle tracking, usando o QRS como referência. O seguimento foi realizado prospectivamente para avaliar a ocorrência de morte e transplante cardíaco (desfecho primário), além de infarto agudo do miocárdio (IAM), acidente vascular encefálico (AVE) e internação por IC. A associação do strain de reservatório, de conduto e de contração ativa com os desfechos foram avaliados por meio de análise univariada e multivariada de regressão de Cox. Resultados: Pacientes apresentaram idade média de 58±12 anos, sendo 62% homens e FE média de 29%±6. O tempo de seguimento médio foi de 2,8 anos. Os desfechos primário e secundário ocorreram em 18 e 54%, respectivamente. O strain de reservatório e de contração ativa estiveram relacionados com os desfechos primários, e o strain de reservatório e conduto estiveram relacionados com o desfecho secundário independentemente da idade, sexo, FE, classe funcional, regurgitação mitral ou grau de disfunção diastólica (p<0,05). Conclusão: O strain de reservatório do AE é um marcador independente de eventos adversos em pacientes portadores de IC e disfunção ventricular moderada e importante. Nossos achados sugerem que o strain do AE pode auxiliar na estratificação de risco de pacientes com IC.Background: Left atrial (LA) strain imaging enables the quantitative assessment of LA function. The clinical relevance of these measurements is dependent on the provision of information incremental to the left ventricular (LV) evaluation, particulary important in heart failure (HF). The aim of this study was analyze the potential prognostic role of LA function in patients with HF. Methods: Echocardiography was undertaken in 217 patients with HF, left ventricular ejection fraction(EF)<40% and sinus rhythm. LA function was analyzed by speckle-tracking, using R-R gating. A prospective follow-up was conducted to report death and cardiac transplantation (primary endpoint), in addition to acute myocardial infarction, stroke and hospital admission (secondary endpoint). The association between LA reservoir, conduit and pump strain with adverse outcomes were assessed using univariate and multivariate Cox regression model. Results: Patients mean age 58±12 years, 62% men and mean EF 29±6%. Mean follow-up time was 2,8 years. The primary and secondary endpoints ocurred in 18 and 54%, respectively. LA reservoir and pump were associated with the primary endpoint, and LA reservoir and conduit were associated with secondary endpoint independently of age, sex, EF, functional class, mitral regurgitation or diastolic function (p<0,05). Conclusion: LA reservoir strain is an independent predictor of adverse events in pacients with moderate and severe HF. This finding suggests that LA strain can help as a marker in the risk stratification of patients with HF.
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Legallois, Damien. "Paramètres biologiques et échocardiographiques et remodelage ventriculaire gauche après syndrome coronarien aigu avec sus-décalage du segment ST Definition of left ventricular remodelling following ST-elevation myocardial infarction: a systematic review of cardiac magnetic resonance studies in the past decade Left atrial strain quantified after myocardial infarction is associated with ventricular remodeling The relationship between circulating biomarkers and left ventricular remodeling after myocardial infarction: an updated review Serum neprilysin levels are associated with myocardial stunning after ST-elevation myocardial infarction Is plasma level of Coenzyme Q10 a predictive marker for left ventricular remodeling after revascularization for ST-segment elevation myocardial infarction ?" Thesis, Normandie, 2020. http://www.theses.fr/2020NORMC429.
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Le remodelage ventriculaire gauche est une complication fréquente des patients ayantprésenté un syndrome coronarien aigu, pouvant conduire à terme à une situation d’insuffisancecardiaque. Il est donc important de connaître les facteurs associés à la survenue d’un remodelageventriculaire afin de dépister plus précocement les patients à plus haut risque d’insuffisance cardiaqueet ainsi optimiser leur prise en charge. Ce travail comprend deux axes. Le premier porte sur larecherche de nouveaux paramètres d’imagerie associés à la survenue du remodelage. Nous avonsdans un premier temps réalisé une revue de la littérature concernant la définition du remodelageventriculaire gauche en imagerie par résonance magnétique. Puis, nous avons conduit deux étudesayant pour but de rechercher une association entre (i) le strain atrial gauche et, (ii) le gradient depression intraventriculaire gauche diastolique, évalués en échocardiographie 24-48 heures après lesyndrome coronarien aigu et le remodelage ventriculaire gauche au cours du suivi. Le second axe portesur les biomarqueurs associés au remodelage ventriculaire post-infarctus. Nous avons réalisé une revuede la littérature au sujet des biomarqueurs qui, dosés lors de l’hospitalisation initiale, sont associés àl’existence d’un remodelage lors du suivi. Nous avons ensuite étudié la valeur prédictrice de deuxbiomarqueurs (la néprilysine et le coenzyme Q10) pour la survenue d’un remodelage ventriculairegaucheLeft ventricular remodeling is a common complication in patients following acutemyocardial infarction and may lead to heart failure. Some baseline parameters are associated withremodeling at follow-up, allowing to better discriminate patients with an increased risk of heart failureto optimize therapeutics. This work has two axes, focused on imaging and biological parametersassociated with left ventricular remodeling, respectively. First, we reviewed past studies that definedremodeling using cardiac magnetic resonance imaging. Then, we studied the association betweensome echocardiographic parameters (left atrial strain and diastolic intraventricular pressure gradient)and left ventricular remodeling after ST-elevation myocardial infarction. In the other axis, wereviewed biomarkers that have been associated with left ventricular remodeling in prior studies. Then,we investigated the association between neprilysin and coenzyme Q10 levels and left ventricularremodeling in STEMI patients
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Cameli, Matteo. "Mechanical and histological disturbances in advanced heart failure and cardiac transplantation". Doctoral thesis, Umeå universitet, Kardiologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-127295.
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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.
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Grandperrin, Antoine. "Entraînement en musculation et remodelage myocardique : Influence du sexe, du niveau de pratique et de la prise régulière de stéroïdes anabolisants Myocardial adaptations after 16 weeks of high-intensity strength training in men and women Androgenic anabolic steroids induce left atrial and left ventricular remodeling and dysfunction in strength athletes Left ventricular dyssynchrony and post-systolic shortenings in young bodybuilders using anabolic-androgenic steroids Myocardial work in athletes using anabolic androgenic steroids and athletes with hypertrophic cardiomyopathy". Thesis, Avignon, 2020. http://www.theses.fr/2020AVIG0717.
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Ces dernières années, la pratique de la musculation s’est largement démocratisée et regroupe aujourd’hui différents types de pratiquants, allant de la personne sédentaire en reprise d’activité au sportif de haut niveau pratiquant le culturisme. L’objectif de ces travaux de thèse a été d’étudier l’impact cardiaque de l’entraînement en musculation chez ces différents types de pratiquants. Une première partie a eu pour objectif d’étudier l’impact longitudinal de 16 semaines d’entrainement en musculation sur la fonction cardiaque d’hommes et de femmes préalablement sédentaires. Le programme d’entraînement, supervisé, a été conçu en respectant les recommandations de l’American College of Sports Medicine (travail à 70% de la charge maximale, 4 séries, 8 à 12 répétitions, 3 séances par semaine, utilisation d’exercices polyarticulaires). Afin d’étudier la cinétique d’adaptation de la morphologie et fonction ventriculaire et atriale, nous avons réalisé une échocardiographie de repos complète, incluant des analyses en "2D-strain", toutes les quatre semaines. Une deuxième partie s’est intéressée aux sportifs de force très entraînés, et plus particulièrement à ceux qui rapportent une utilisation régulière de stéroïdes anabolisants en complément de leur entrainement. De nombreuses études rapportent des effets délétères de ces substances, avec notamment un impact négatif sur la morphologie et la fonction cardiaque qui peut conduire à la survenue de morts subites. Néanmoins, peu d’études ont à ce jour exploité les derniers outils disponibles en échocardiographie afin de comprendre les dysfonctions engendrées. Ainsi, à partir d’analyses en "2D-strain", nous avons mis en place une évaluation globale et régionalisée de la morphologie et fonction ventriculaire et atriale gauche afin d’étudier les mécanismes impliqués dans les altérations. Nous avons complété ces analyses par une étude de l’asynchronisme intra-ventriculaire. Enfin, nous avons confronté ce modèle de sportifs utilisant des stéroïdes anabolisants à des sportifs ayant une hypertrophie cardiomyopathique afin d’étudier le remodelage potentiellement pathologique engendré par les stéroïdes anabolisants. Dans cette dernière partie, une évaluation novatrice du travail myocardique a été réalisée afin de tenir compte des conditions de charge et de discriminer un peu plus nos populationsStrength training is increasingly practiced by previously untrained people or by experienced athletes. This work aimed to evaluate cardiac adaptations to strength training over these different populations. In a first time, we evaluated the longitudinal impact of 16-weeks strength training on the cardiac function of previously untrained women and men. The American College of Sports Medicine recommendations were used to build the training program (i.e. training at 70% of the repetition maximum, 4 sets, 8-12 repetitions, 3 times a week with polyarticular exercices). 2D-strain echocardiography was used to assess both left ventricular and atrial morphology and function. In a second time, we aimed to evaluate the cardiac function of strength-trained athletes, which used androgenic anabolic steroids. While previous studies reported an alteration of cardiac function in this population, with sudden-death frequently reported, any study used 2D-strain parameters to understand the dysfunctions. In this context, we used 2D-strain analysis to evaluate global and regional myocardial function in order to evaluate the underlying mechanisms of left ventricular and left atrial functions, with a specific evaluation of intra-ventricular dyssynchrony. Finally, we aimed to compare our athletes using androgenic anabolic steroids users to athletes with hypertrophic cardiomyopathy to assess the probably pathological remodelling generates by anabolic androgenic steroids. In this study, we evaluate myocardial work, a new tool in echocardiography, which take into account load conditions and could better discriminate our populations
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Huber, Adrian Thomas. "Multi-organ non-invasive tissue characterization of fibrosis, adipose tissue, edema and inflammation with magnetic resonance (MR) imaging : applications to myocardium, skeletal muscle and liver interactions Cardiac MR strain: a noninvasive biomarker of fibro-fatty remodeling of the left atrial myocardium Comparison of MR T1 and T2 mapping parameters to characterize myocardial and skeletal muscle involvement in systemic Idiopathic Inflammatory Myopathy (IIM) Non-invasive differentiation of acute viral myocarditis and idiopathic inflammatory myopathy with cardiac involvement using magnetic resonance imaging T1 and T2 mapping CT predicts liver fibrosis: Prospective evaluation of morphology- and attenuationbased quantitative scores in routine portal venous abdominal scans". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS135.
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Cette thèse réalise une preuve de concept pour quantifier la déformation de l’oreillette gauche (OG) en IRM, ainsi que la relaxométrie IRM dans le myocarde, dans les muscles squelettiques et dans le foie. Grâce à l’interaction entre radiologues et ingénieurs, deux logiciels différents ont été développés, appliqués et validés pour l'analyse de la déformation myocardique multi-chambre et pour la cartographie quantitative du T1 multi-organes. La première publication a montré une forte corrélation de la déformation de l’OG, avec le degré de remplacement fibro-graisseux en histologie. Ce biomarqueur d'imagerie fonctionnelle est prometteur, puisque le remodelage structurel du myocarde est un substrat morphologique connu du dysfonctionnement électro-physiologique et de la fibrillation atriale. La deuxième publication a démontré l'influence de la composition et de la vascularisation de différents tissus sur les paramètres cartographiques T1. ΔT1 (prise de contraste musculaire relative) et EHF (prise de contraste musculaire normalisée par la prise de contraste dans le sang) ont été introduits comme alternatives simples au volume extracellulaire (ECV). Dans la troisième publication, les paramètres de relaxométrie appliqués aux muscles squelettiques ont permis une discrimination entre patients avec myocardite aiguë et patients avec des myosites systémiques. La quatrième publication a introduit le T1 du foie pour quantifier l’insuffisance cardiaque chez des patients avec des cardiomyopathies idiopathiques dilatées, montrant de meilleures performances que les paramètres fonctionnels établis tels que les volumes, la fraction d'éjection ou la déformation myocardiqueThis thesis provides a proof of concept for MR atrial strain, as well as MR relaxometry in the myocardium, in skeletal muscles and in the liver. Thanks to a close interaction between radiologist and software engineers, two different softwares were developed, applied and validated: one for multiorgan T1 mapping in the myocardium, skeletal muscle and liver, another one for cardiac four-chamber strain analysis and volumetry. The first publication showed a strong correlation of LA strain with the degree of fibro-fatty replacement in histology. Such functional imaging biomarker in combination with LA volumetry could help to guide clinical decisions, since myocardial structural remodeling is a known morphologic substrate of LA dysfunction, atrial fibrillation and adverse outcome. In the second publication, MR relaxometry parameters applied to the myocardium and skeletal muscles in IIM patients and healthy volunteers were used as a model to demonstrate influences of different tissue composition and vascularization on T1 mapping parameters. ΔT1 and EHF were introduced as simple alternatives to ECV in highly vascularized tissues such as the myocardium. In the third publication, MR relaxometry parameters applied to the skeletal muscls allowed for an accurate discrimination of AVM and IIM with cardiac involvement. However, when applied to the myocardium, parametric mapping did not separate between the two groups. The fourth publication introduced native T1 of the liver an easily accessible and accurate non-invasive imaging associate of congestive HF in IDCM patients with better performance than established functional parameters such as LV volumes, ejection fraction or strain
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Fernandes, Rafael Modesto. "Correlação entre o strain bidimensional do átrio esquerdo com os desfechos clínicos da síndrome coronariana aguda sem supradesnivelamento do segmento ST". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/98/98131/tde-04102017-112703/.
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Introdução: A disfunção atrial esquerda está associada a pior prognóstico em diversas situações clínicas. O método de strain bidimensional do átrio esquerdo permite avaliar de forma direta todas as fases da função atrial. Pouco se conhece sobre o comportamento das fases da função atrial esquerda em pacientes com síndrome coronariana aguda. O objetivo desse estudo foi correlacionar as funções de reservatório, conduto e contração do átrio esquerdo com desfechos adversos cardiovasculares em pacientes com síndrome coronariana aguda sem supradesnivelamento do segmento ST. Método: Esse estudo recrutou prospectivamente 109 pacientes com diagnóstico de infarto agudo do miocárdio sem elevação do segmento ST e de angina instável de risco moderado ou alto pelo escore GRACE para realização de ecocardiograma nas primeiras 72 horas. A função atrial foi avaliada por parâmetros ecocardiográficos convencionais e pelo strain bidimensional obtido pela média das janelas apicais 2 e 4 câmaras. O desfecho primário foi avaliado em até um ano de seguimento e foi composto pelos seguintes eventos adversos: óbito, insuficiência cardíaca nova, nova internação por síndrome coronariana aguda ou por insuficiência cardíaca, angina estável com necessidade de nova intervenção coronariana, arritmia (fibrilação atrial ou taquicardia ventricular) e acidente vascular cerebral. Os desfechos secundários foram os combinados desses eventos. Resultados: As médias do strain de reservatório, conduto e contração foram de 25% ± 8, 12% ± 5 e 12% ± 4, respectivamente. O desfecho primário teve uma incidência de 31,8% em até um ano e apresentou uma correlação significativa com o strain de reservatório (HR= 0,92; IC95% 0,88-0,96; p<0,001), de conduto (HR= 0,87; IC95% 0,81-0,94; p<0,001) e de contração (HR= 0,90; IC95% 0,84-0,98; p=0,011). Análise multivariada envolvendo variáveis clínicas e as de função atrial esquerda demonstraram que o strain de reservatório (p=0,03) e de conduto (p=0,046) se mantiveram significativos como preditores do desfecho primário. O strain de conduto se manteve significativo no desfecho combinado de óbito e insuficiência cardíaca (HR= 0,82; IC95% 0,74-0,91; p<0,001) mesmo após análise multivariada com parâmetros clínicos (p<0,001) e ecocardiográficos (p=0,049). Conclusão: A avaliação da função atrial esquerda por meio do strain bidimensional se correlacionou significativamente com desfechos adversos em pacientes com síndrome coronariana aguda sem elevação do segmento ST. O strain de reservatório e de conduto foram marcadores prognósticos independentes para o desfecho primário quando comparados às variáveis clínicas. Já para o desfecho combinado de óbito e insuficiência cardíaca, o strain de conduto foi um preditor independente mesmo após ajustado para variáveis clínicas e ecocardiográficas.Background: Left atrial dysfunction is associated with worse prognosis in several clinical situations. The left atrial two-dimensional strain method allows direct evaluation of all phases of atrial function. There are few studies on the behavior of the various stages of left atrial function in patients with acute coronary syndrome. The aim of this study was to correlate the functions of reservoir, conduit and contraction of the left atrium with adverse cardiovascular outcomes in patients with non-ST elevation acute coronary syndrome. Method: This study prospectively recruited 109 patients with a non-ST-segment elevation myocardial infarction and unstable angina with moderate or high risk by GRACE score and echocardiography parameters were collected within the first 72 hours of admission. The atrial function was evaluated by conventional echocardiographic parameters and the two-dimensional strain obtained by the mean of the apical two- and four-chamber views. The primary endpoint was assessed during the 1 year follow-up period and was composed of theses adverse events: death, heart failure, rehospitalization for acute coronary syndrome or heart failure, stable angina requiring new coronary intervention, arrhythmia (atrial fibrillation or ventricular tachycardia) and stroke. Secondary outcomes were those combined for these events. Results: The means of reservoir, conduit and contraction strain were 25% ± 8, 12% ± 5 and 12% ± 4, respectively. The primary endpoint occurred in 31.8% patients during the 1 year follow-up period and had a statistically significant correlation with the reservoir strain (HR = 0.92, 95% CI: 0.88-0.96, p <0.001), conduit strain (HR = 0.87, 95% CI: 0.81-0.94, p <0.001) and contraction strain (HR = 0.90, 95% CI: 0.84-0.98, p = 0.011). Multivariate analysis involving clinical variables and left atrial function showed that the reservoir strain (p = 0.03) and conduit (p = 0.046) were independent predictors of endpoint primary. The conduit strain were statistically significant in the combined outcome of death and heart failure (HR = 0.82, 95% CI: 0.74-0.91, p <0.001) even after multivariate analysis with clinical (p <0.001) and echocardiography parametrs (p = 0.049). Conclusion: Evaluation of left atrial function by two-dimensional strain correlated significantly with adverse outcomes in patients with non-ST elevation acute coronary syndrome. The reservoir and conduit strain were independent prognostic markers for the primary endpoint when compared to clinical parametrs. For the combined outcome of death and heart failure, the conduit strain was an independent predictor even after adjusting for clinical and echocardiographic variables.
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Lisi, Matteo. "Insights into left atrial response to pressure and volume overload". Doctoral thesis, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-127294.
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The general purpose of this thesis is to establish the ability of Speckle Tracking Echocardiography (STE) in assessing left atrial (LA) response to pressure and volume overload respectively in aortic stenosis (AS) and mitral regurgitation (MR), and to evaluate its accuracy in predicting LA and right ventricular (RV) fibrosis in patients with end-stage heart failure (HF) undergoing heart transplantation (HTx). I demonstrated that assessment of left ventricular (LV) long axis systolic velocity and amplitude of excursion is more sensitive than simple determination of ejection fraction (EF) for revealing the beneficial impact of MR surgery on overall LV systolic performance. Severe symptomatic AS is associated with LA enlargement and compromised mechanical function with a high incidence of peri-operative atrial fibrillation (AF). Valve replacement reverses these abnormalities and regains normal atrial function, a behaviour which is directly related to the severity of pre-operative LV outflow tract obstruction. Early identification of LA size and function disturbances, as shown by myocardial strain measurements might contribute to better patient’s recruitment for a safe valve replacement. In late stage HF patients, the right ventricle is enlarged, with reduced systolic function due to significant myocardial fibrosis. RV free wall myocardial deformation is the most accurate function measure that correlates with the extent of RV myocardial fibrosis and functional capacity. In patients with preserved EF, severe MR masks LV and LA myocardial dysfunction and correlates with symptoms and post-operative cavity function instability. Three months after MVR, the underlying myocardial disturbances are unmasked suggesting that most pre-operative measurements are subject to loading conditions. Finally LA volume and PALS remain the main predictors of post-operative AF, thus should be used for stratifying surgical risk. STE has been shown to accurately determine the severity of impairment of LA myocardial function shown by suppressed PALS which was the strongest predictor of the presence and extent of fibrosis, over and above other structure and function parameters. These findings may assist in better stratifying patients with end stage HF and identifying particularly those requiring HTx.
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Borkowski, Philip. "Insights into atrial function using speckle tracking strain: report of a new, modified method". Thesis, 2014. https://hdl.handle.net/2144/15052.
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Speckle tracking echocardiography (STE) is a relatively new imaging modality that enables the direct measurement of active contractile myocardial tissue in an offline analysis. This is accomplished through a software algorithm that tracks collections of acoustic markers, known as 'speckles', that are unique to a given section of myocardium. By measuring the displacement of these 'speckles' as the heart contracts and relaxes, STE produces parameters of the strain, or percent change in length, exhibited by the myocardium. As multiple studies have shown, this strain data produced by tracking of the global left atrium has the ability to accurately assess the physiologic functions of the atrium as a reservoir, conduit and booster pump in the cardiac cycle. Despite these valuable correlations, there are noted problems with STE regarding acoustic cluttering and disappearance of 'speckles' that can occur as the selected region of interest moves out of the field of view or becomes obscured. These problems may be increased when tracking an extended region of myocardium. Therefore, this present study sought to test a new method of assessing left atrial function with STE strain analysis by focusing on a concise region of the atrium, specifically the interatrial septum.
To test this, the echocardiograms of 37 patients were obtained and grouped according to the designation of their cardiac function as normal (n=11), abnormal (n=12), or exhibiting signs of cardiac amyloidosis (n=14). In all patients, STE strain analysis was performed on the both the global left atrium and the interatrial septum. Measurements of the mean peak strain observed in the resultant strain curves were recorded for both STE scans of each patient. The curves produced by the tracking the segments of the entire atrium (6 segments) and interatrial septum (3 segments) were compared based on the exhibited changes in strain seen in the relative shapes of the curves, as well as the spread of the segmental strain curves about the calculated mean strain curve. Additionally, the number of segments that were either unsuccessfully or incorrectly tracked was recorded as a measure of the accuracy of STE. As a final step, the interatrial strain curves of four selected patients in the various states of ventricular diastolic dysfunction were chosen and compared with data obtained from scans of mitral flow echocardiography and tissue Doppler imaging (TDI) in an attempt to correlate the exhibited changes in strain shown in the interatrial septum with the physiologic functions of the atrium during ventricular diastole.
The results showed that the mean peak strain of the global atrial strain trace decreased from normal (41.32%±10.8) to abnormal (21.69%±13.8) to the amyloid group (10.41%±6.9). This trend was echoed in the mean peak strain measured in the interatrial septum, as measured in normal (64.2%±15.6), abnormal (28.37%±13.4) and amyloid groups (12.21%±12.1). When the strain curves of the entire atrium and interatrial septum were compared, they demonstrated similar patterns in the timing of changes in strain, however the strain curves of the individual interatrial septum segments showed a much more concise grouping about the mean strain curve and were less likely to exhibit discordant segmental strain curves that deviated from the pattern established by all other segments in the trace. Additionally, within the STE scans of the global atrium, the interatrial septum exhibited a higher percentage of successfully tracked segments than did the lateral atrial wall; this trend was universally exhibited in all three groups. Finally, the interatrial septum strain curves, mitral flow echocardiography and TDI scans all demonstrated similar indications of left atrial function in the four selected patients.
Ultimately, STE strain analysis of the interatrial septum appears to be a more accurate method of tracking the atrial myocardium than STE tracing of the global left atrium. Furthermore, it shows viable potential as a method for assessing the global physiologic function of the left atrium, as indicated by the similarities between the trends exhibited by these STE scans and the data gathered from scans produced by mitral flow echocardiography and TDI.
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Navarra, Jenny-Lou. "Prognostische Relevanz der Magnetresonanztomographie-Feature-Tracking-basierten quantifizierten Vorhoffunktion nach akutem Myokardinfarkt". Doctoral thesis, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-12C3-A.
Texto completoLibros sobre el tema "Left atrial strain"
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Rosca, Monica, Sergio Mondillo y Kim O’Connor. Left atrium. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0022.
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The left atrium (LA) in a close interdependence with the left ventricle plays an essential role in the overall cardiovascular performance. The impact of LA remodelling on prognosis and risk stratification has gathered increasing evidence. With advances in imaging technology, the assessment of LA size and function become more accessible and precise. LA volume provides the most accurate estimate of LA size and superior prognostic information. Accounting for complex geometry and motion, three-dimensional echocardiography emerges as the preferred technique for the assessment of dynamic changes in LA volume. The assessment of LA function, providing important pathophysiological information, can add consistency in establishing the clinical role of LA remodelling. It is essential to fully understand the strengths and weaknesses of conventional and new echocardiographic techniques used to evaluate LA function. Atrial strain and strain rate parameters are less load dependent and have higher sensitivity in assessing LA function than conventional parameters. However, the lack of standardization and incomplete data regarding their prognostic value limits their routine use in current clinical practice.
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Haugaa, Kristina H., Francesco Faletra y João L. Cavalcante. Cardiac rhythm disorders. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0063.
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Cardiac rhythm disorders require diagnostic, prognostic, and guidance of therapeutic procedures by echocardiography. The most common sustained cardiac arrhythmia is atrial fibrillation (AF) leading to an increased risk for mortality, heart failure, and thromboembolic events. Echocardiography is performed to assess the aetiology of AF which most commonly is associated with diseases leading to enlarged atria. Furthermore, echocardiography is crucial to evaluate thromboembolic risk by assessing the morphology and function of the left atrial appendage among other parameters. Non-invasive imaging modalities including two-dimensional transthoracic (TTE) and transoesophageal echocardiography (TOE) with three-dimensional imaging are often indicated. Finally, TOE can help in the preprocedural planning and providing guidance for interventions such as pulmonary vein ablation and percutaneous left atrial appendage closure. In patients with ventricular arrhythmias, TTE is the first-line diagnostic tool for assessing the aetiology of ventricular arrhythmias. Ischaemic heart disease, either acute or chronic fibrosis, is the most common causes of ventricular tachycardias. Left ventricular ejection fraction remains the most important parameter for indication of an implantable cardioverter defibrillator for primary prevention therapy, although newer strain echocardiographic measures may add incremental prognostic information.
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De Sutter, Johan, Piotr Lipiec y Christine Henri. Heart failure: preserved left ventricular ejection fraction. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0028.
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Nearly half of all patients with heart failure present with a preserved left ventricular ejection fraction (HFPEF). HFPEF is a pathophysiologically and clinically heterogeneous disease with an overall similar outcome to heart failure patients with a reduced ejection fraction. It is predominantly seen in elderly patients and comorbidities such as obesity, diabetes, hypertension, a sedentary lifestyle, and myocardial ischaemia play important roles in its development. In this chapter the conventional echocardiographic hallmarks of HFPEF including a preserved ejection fraction, left ventricular hypertrophy, left atrial dilatation, diastolic dysfunction, and pulmonary hypertension are presented. For the evaluation of left ventricular diastolic dysfunction, it is important to keep in mind that no single echocardiographic parameter is sufficiently accurate and reproducible to be used in isolation to make a diagnosis of diastolic dysfunction. The value of newer techniques including three-dimensional echocardiography and longitudinal strain assessment for the diagnosis and follow-up of HFPEF patients are promising but require further evaluation. As exercise-induced dyspnoea may be the first manifestation of HFPEF, the role of exercise echo (or diastolic stress testing) with evaluation of exercise-induced changes in left ventricular filling pressure and pulmonary artery systolic pressure is also presented. This chapter ends with a discussion on the echocardiographic parameters that can be used for risk stratification and follow-up of HFPEF patients.
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Galderisi, Maurizio y Sergio Mondillo. Assessment of diastolic function. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0009.
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Modern assessment of left ventricular (LV) diastolic function should be based on the estimation of degree of LV filling pressure (LVFP), which is the true determinant of symptoms/signs and prognosis in heart failure.In order to achieve this goal, standard Doppler assessment of mitral inflow pattern (E/A ratio, deceleration time, isovolumic relaxation time) should be combined with additional manoeuvres and/or ultrasound tools such as: ◆ Valsalva manoeuvre applied to mitral inflow pattern. ◆ Pulmonary venous flow pattern. ◆ Velocity flow propagation by colour M-mode. ◆ Pulsed wave tissue Doppler of mitral annuls (average of septal and lateral E′ velocity).In intermediate doubtful situations, the two-dimensional determination of left atrial (LA) volume can be diagnostic, since LA enlargement is associated with a chronic increase of LVFP in the absence of mitral valve disease and atrial fibrillation.Some new echocardiographic technologies, such as the speckle tracking-derived LV longitudinal strain and LV torsion, LA strain, and even the three-dimensional determination of LA volumes can be potentially useful to add further information. In particular, the reduction of LV longitudinal strain in patients with LV diastolic dysfunction and normal ejection fraction demonstrates that a subclinical impairment of LV systolic function already exists under these circumstances.
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D’Andrea, Antonello, André La Gerche y Christine Selton-Suty. Systemic disease and other conditions: athlete’s heart. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0055.
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The term ‘athlete’s heart’ refers to the structural, functional, and electrical adaptations that occur as a result of habitual exercise training. It is characterized by an increase of the internal chamber dimensions and wall thickness of both atria and ventricles. The athlete’s right ventricle also undergoes structural, functional, and electrical remodelling as a result of intense exercise training. Some research suggests that the haemodynamic stress of intense exercise is greater for the right heart and, as a result, right heart remodelling is slightly more profound when compared with the left heart. Echocardiography is the primary tool for the assessment of morphological and functional features of athlete’s heart and facilitates differentiation between physiological and pathological LV hypertrophy. Doppler myocardial and strain imaging can give additional information to the standard indices of global systolic and diastolic function and in selected cases cardiac magnetic resonance imaging may help in the diagnosis of specific myocardial diseases among athletes such as hypertrophic cardiomyopathy, dilated cardiomyopathy, or arrhythmogenic right ventricular cardiomyopathy.
Capítulos de libros sobre el tema "Left atrial strain"
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Bansal, Manish y Ravi Kasliwal. "Incremental Value of Left Atrial Strain in Patients with Atrial Fibrillation". En Atrial Fibrillation Update: A Textbook of Cardiology, 324. Jaypee Brothers Medical Publishers (P) Ltd., 2017. http://dx.doi.org/10.5005/jp/books/13034_56.
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Ernande, Laura. "Hypertension and diabetes". En ESC CardioMed, editado por Frank Flachskampf, 445–47. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0090.
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Both hypertension and diabetes mellitus (DM) are risk factors for coronary artery disease, resulting in a high risk of heart failure. They also directly impact the heart, leading to hypertensive heart disease and diabetic cardiomyopathy and also potentially causing heart failure. The hypertensive heart is characterized by left ventricular hypertrophy and frequently left atrial dilation. DM is also associated with an increased left ventricular mass. Left ventricular hypertrophy has an important prognostic value both in hypertensive and diabetic patients and may regress with antihypertensive medications. The differential diagnosis between hypertensive heart disease and hypertrophic cardiomyopathy can be sometimes challenging and requires a careful evaluation of the echocardiogram but also of the family history, electrocardiographic abnormalities, or the location of late gadolinium enhancement on cardiovascular magnetic resonance imaging. Hypertension and DM also influence ageing-related left ventricular remodelling. Diastolic dysfunction is frequent both in hypertensive and diabetic patients and is predictive of cardiac events and heart failure. However, diastolic dysfunction in diabetic patients seems to be more associated with age and co-morbidities such as obesity and hypertension than with DM itself. The presence of diastolic dysfunction predicts cardiac events and heart failure in those patients. Both hypertension and DM are risk factors for heart failure with preserved but also with reduced and mid-range ejection fraction. Therefore, left ventricular ejection fraction is a major parameter to evaluate in those patients. Myocardial strain is decreased both in hypertensive and in diabetic patients with normal left ventricular ejection fraction allowing the detection of subclinical systolic alteration and providing incremental prognostic value.
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Maceira, Alicia M. y Alistair A. Young. "Global and regional cardiac function". En The EACVI Textbook of Cardiovascular Magnetic Resonance, editado por Massimo Lombardi, Sven Plein, Steffen Petersen, Chiara Bucciarelli-Ducci, Emanuela R. Valsangiacomo Buechel, Cristina Basso y Victor Ferrari, 92–102. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198779735.003.0014.
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Cardiovascular magnetic resonance is currently the most accurate and reproducible method for the measurement of biventricular global and regional systolic function, as well as diastolic and atrial function. Regional wall motion can be visually evaluated and quantified with tissue tagging or feature tracking analysis techniques. Wall motion analysis is usually performed at rest but can also be done with low-dose and high-dose dobutamine. Segmental strain is best measured with tissue tagging or displacement-encoded phase contrast imaging. Current analysis software enables the measurement of ventricular volumes throughout the cardiac cycle, and assessment of left and right ventricular diastolic function can be done by evaluating the time–flow curve, derived from the volume–time curve obtained in the volumetric analysis. Although contrast between flowing blood and the myocardium in cardiac cine images is typically excellent, the precise placement of the contours is reader-dependent and training is highly recommended due to the subjective nature of contour placement.
Actas de conferencias sobre el tema "Left atrial strain"
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Satriano, Alessandro, Edward J. Vigmond y Elena S. Di Martino. "A Feature-Based Mechano-Electric Finite Element Model of the Left Atrium With Pressure-to-Mitral-Flow Coupling". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80927.
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The modeling of complex biological systems requires many degrees of sophistication. Among them, we can enumerate heterogeneous tissue properties, a complex geometry that can be obtained only through proper imaging techniques and the interaction of the organ of interest with the surrounding structures. In the case of the left atrium, three physical domains govern its behavior: mechanical, electrical and fluidic. Different mechanical conditions, in terms of stresses and consequent strains, affect the electrical activity occurring across the tissue, and jointly, the mechanical and electrical activities regulate the correct and timely contraction of the chamber. A strongly coupled mechano-electrical model of the atrial chamber cannot be accomplished without accounting for the directional heterogeneity of the tissue, because both the electrical and the mechanical properties of the tissue are not isotropic. The fluid entering from the pulmonary veins during the filling phase of the atrium causes the pressure in the atrium to rise until the difference between the pressure in the ventricular and atrial chamber is negative (higher atrial pressure) and the mitral valve opens. After the opening of the valve, two distinct emptying phases ensue, a passive and an active one. During the passive emptying phase the pressure in the ventricle slowly rises, affecting the flow through the valve itself. During the active phase, the contraction of the atrium walls causes the pressure in the atrium to rise. Our laboratory has developed a finite element dynamic mechano-electric model of the left atrium behavior starting from multi-detector computed tomography images. We accounted for the directional heterogeneity of the tissue because both the electrical and the mechanical properties of the tissue are not isotropic. As a first step, we modeled the effect of the blood flow in the atrium (fluidic domain) by assuming a temporally varying pressure across the cardiac cycle. In spite of this assumption, i.e. of a “dry” pressure-driven model, we cannot ignore the contribution to the presence of the left ventricle downstream of the mitral valve. In fact, the ventricular pressure counteracts the volume decrease due to the passive and active emptying on the atrial chamber. Moreover, during the active phase of the atrium cycle, the atrial pressure rises in response to the resistance of the mitral flow to time changes (c wave).
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Wang, Qian y Wei Sun. "Patient-Specific Finite Element Modeling of Mitral Valve Dynamic Deformation". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80750.
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Mitral valve is a two-leaflet valve that is located between the left atrium and the left ventricle of the heart. In order to successfully replace or repair mitral valve and develop effective prosthetic devices, it is critical to understand the in vivo mechanics of the normal mitral valve. Although research has been conducted to investigate animal mitral valve strains by in vivo experiments, it is still very challenging to obtain accurate in vivo stress and strain information of the human mitral valve.
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Varela, Marta, Sandro Queiros, Mustafa Anjari, Teresa Correia, Andrew P. King, Anil A. Bharath y Jack Lee. "Strain maps of the left atrium imaged with a novel high-resolution CINE MRI protocol*". En 2020 42nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) in conjunction with the 43rd Annual Conference of the Canadian Medical and Biological Engineering Society. IEEE, 2020. http://dx.doi.org/10.1109/embc44109.2020.9175383.
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Shultz, Tyler, Manuel Rauch y Ellen Kuhl. "Collagen Orientation in the Anterior Mitral Valve Leaflet". En ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53191.
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The Mitral Valve (MV) serves to ensure unidirectional blood flow from the pulmonary to systemic circulation. When the MV fails to function correctly, backflow from the left ventricle to left atrium occurs during heart contraction. This condition is called Mitral Valve Regurgitation (MVR) and is estimated to affect 2 to 2.5 million people in the United States alone [1]. Surgical techniques exist to repair MVR, and each affects the structure of the valve in a different way [2]. As the main load-bearing structure in the leaflets, collagen fibers have a tremendous impact on how the leaflets are able to support pressure loads, and their orientation has great functional implications. The goal of this study is therefore to investigate the microstructure of mitral valve tissue. Since collagen makes up approximately 60% of the dry weight of the leaflet [3], we focused our study on this macromolecule. In a complementary in-vivo study, we computed mitral leaflet strains in radial and circumferential direction using a continuum mechanical approach based on the 4D coordinates of 23 radiopaque markers sewn onto the anterior MV leaflet [4]. Results shown in Figure 1. As clearly seen from the figure, strains exhibit pronounced anisotropy. We expect that comparison of the collagen orientation in the leaflet with the these strain profiles will enhance our knowledge of the role of collagen in MV mechanics and the effect that potential surgical interventions may have on MV functionality. While collagen orientation has been determined using Small Angle Light Scattering [5], Polarized Light Microscopy [5], and X-ray Diffraction [6], histological methods to characterize the collagen orientation over the entire leaflet have not been reported. Therefore, we will study the orientation of collagen throughout the anterior ovine MV leaflet using tissue histology.