1,720,962 research outputs found
Imaging of Myocardial Fibrosis and Its Functional Correlates in Aortic Stenosis: A Review and Clinical Potential
No full textPatients with severe aortic stenosis (AS) show progressive fibrotic changes in the myocardium, which may impair cardiac function and patient outcomes even after successful aortic valve replacement. Detection of patients who need an early operation remains a diagnostic challenge as myocardial functional changes may be subtle. In recent years, speckle tracking echocardiography (STE) and cardiac magnetic resonance mapping have been shown to provide complementary information for the assessment of left ventricular mechanics and identification of subtle damage by focal or diffuse myocardial fibrosis, respectively. Little is known, however, about how focal and diffuse myocardial fibrosis occurring in severe AS are related to measurable functional changes by echocardiography and to which extent both parameters have prognostic and diagnostic value. The aims of this review are to discuss the occurrence of focal and diffuse myocardial fibrosis in patients with severe AS and to explore their relation with myocardial function, determined by STE, as well as the prognostic and diagnostic potential of both parameters
Outcome of Paradoxical Low‐flow Low‐gradient Severe AS Following TAVI: Paradoxical vs. Parallel to Outcome of High Gradient AS
No full textEchocardiography Markers Of myocardial tissue Deformation as Independent predictors of rhythm outcome after catheter ablation for Atrial Fibrillation
Full text linkAF recurrence is common post catheter ablation. AF recurrence is associated with symptomatic deterioration, thromboembolic events, hospital admissions and worse prognosis. Therefore, definition of an accurate and easily obtainable predictor of AF recurrence is of crucial importance.
AF is associated with left atrial (LA) structural remodeling and functional deterioration due to a variable degree of myocardial hypertrophy, disarray, apoptosis and fibrosis. In clinical practice, M mode and B mode echocardiography-derived indices of LA size are routinely used to assess left atrium (LA). However, these parameters have important limitations to describe complex myocardial changes associated with AF.
Speckle tracking is an echocardiographic technique which has gradually gained relevance in the last decade. Quantification of myocardial deformation based on SLE overcomes most of the limitations of classic echocardiography and provides an early detection of myocardial funticonal impairment. Today, its feasibility and usefulness to measure LA function are highly supported by literature and several studies demonstrated that STE could provide additional prognostic information beyond conventional echocardiographic parameters.
Recent advances in echocardiography equipment and image post-processing allow an assessment of LA strain and strain rate. The speckle-tracking echocardiography (STE)-derived LA longitudinal strain has been shown to be an accurate and reproducible parameter to evaluate LA longitudinal shortening. Furthermore, LA strain has significantly correlated with underlying LA fibrosis.
A recent standardization of speckle tracking analysis regarding all cardiac chambers supported the integration of STE in diagnostic and prognostic protocols in daily practice. This suggests that LA strain provides a comprehensive and quantitative assessment of LA structure and function. Hence, it is tempting to speculate that the analysis of LA strain will show high accuracy to predict AF recurrence post catheter ablation. However, LA strain can be affected by several factors not related to LA structural damage such as loading conditions or arrhythmias. Moreover, in the real-world setting, the value of LA strain to predict AF recurrence following catheter ablation is not known.
Therefore, the aim of the present study is fourfold:
(1. To evaluate feasibility of STE-derived strain assessment in patients undergoing catheter ablation for paroxysmal or persistent AF.
(2. To determine the acute effect of catheter ablation on LA structure and function.
(3. To define echocardiographic predictors of AF recurrence during long-term follow-up.
(4. To define the role of LA strain in the diagnosis of HFpEF in patients with history of AF
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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