1,721,032 research outputs found
Letter by Barison et al Regarding Article, "Familial Clustering of Mitral Valve Prolapse in the Community"
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Role of tissue characterization by Cardiac Magnetic Resonance in the diagnosis of constrictive pericarditis
No full textCardiac Magnetic Resonance (CMR) allows evaluation of the functional and flow changes in pericardial constriction as well as detection of acute pericardial inflammation, fusion and thickening of pericardial layers and pericardial effusion. We sought to evaluate the diagnostic role of tissue characterization by CMR in constrictive pericarditis (CP). We performed a CMR exam in 70 patients (mean age 58 ± 16) with clinical suspicion of constrictive pericarditis and constrictive pattern at echocardiography and/or catheterization. A multiparametric CMR approach was used to evaluate the initial diagnostic suspicion. A clinical follow-up was performed in all patients for a median of 551 days. The diagnosis of CP was confirmed in 53 patients while 12 patients presented signs of predominant pericardial active inflammation suggesting a diagnosis of transient constrictive pericarditis and five presented effusive-constrictive pericarditis. Patients with a final diagnosis of CP had worse prognosis than those with transient constrictive or effusive constrictive pericarditis. The presence of myocardial late gadolinium enhancement was associated to adverse events. Results of the current study confirmed the value of CMR in the differential diagnosis of pericardial disease. A multiparametric CMR approach allowed to distinguish between active inflammation, chronic pericarditis with constriction and effusion without inflammation
Pharmacological approaches to coronary microvascular dysfunction
No full textIn recent decades coronary microvascular dysfunction has been increasingly identified as a relevant contributor to several cardiovascular conditions. Indeed, coronary microvascular abnormalities have been recognized in patients suffering acute myocardial infarction, chronic stable angina and cardiomyopathies, and also in patients with hypertension, obesity and diabetes. In this review, we will examine pathophysiological information needed to understand pharmacological approaches to coronary microvascular dysfunction in these different clinical contexts. Well-established drugs and new pharmacological agents, including those for which only preclinical data are available, will be covered in detail. (C) 2014 Published by Elsevier Inc
Usefulness of Combined Functional Assessment by Cardiac Magnetic Resonance and Tissue Characterization Versus Task Force Criteria for Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy
No full textCurrent task force criteria (TFC) of cardiac magnetic resonance (CMR) for the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC/D) were generated by comparing probands (mean age of 44 years) to healthy participants of the multi-ethnic study of atherosclerosis (mean age of 60 years). These age differences may be a selection bias because right ventricular end-diastolic volume index decreases 4.6% per decade. Moreover, fat infiltration and late gadolinium enhancement were not included. We evaluated the diagnostic accuracy of TFC using the same methodology used by the task force but comparing probands and age- and gender-matched healthy controls and considering also other morphofunctional and tissue abnormalities detected by CMR. Forty-seven probands with previous diagnosis of ARVC/D (excluding probands if CMR was used for diagnosis) were compared with 216 age- and gender-matched healthy controls. TFC had optimal specificity (100%) but poor sensitivity (20% for major and 13% for minor criteria). The presence of any pre- and post-contrast signal abnormalities had 100% specificity and 81% sensitivity. The best diagnostic accuracy (98%) was achieved by the combined evaluation of any right ventricular wall motion abnormality (excluding hypokinesia) with any signal abnormality (including left ventricular fat infiltration and late gadolinium enhancement) yielding a 100% specificity and 96% sensitivity. Left ventricular was involved in 45% of the probands. Current TFC for CMR presented optimal specificity but poor sensitivity to identify patient with ARVC/D. Signal and wall motion parameters of CMR should be considered together to achieve the best diagnostic accuracy for the diagnosis of ARVC/D
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
HYPERTROPHIC CARDIOMYOPATHY: RELATIONSHIP BETWEEN MYOCARDIAL ISCHEMIA,FIBROSIS AND CLINICAL STATUS
No full textHypertrophic cardiomyopathy (HCM) is a genetic disorder that is typically inherited in an autosomal dominant fashion. There are defects in several of the genes encoding for the sarcomeric proteins, such as myosin heavy chain, actin, tropomyosin, and titin. Multiple mutations have been identified, with genotype-specific risks for mortality and degree of hypertrophy. The disorder has a variable clinical presentation and carries a high incidence of sudden death. HCM is the leading cause of sudden cardiac death in young population. However, many patients may remain stable over long periods of time and then suddenly they may present adverse events: unexpected death, embolic stroke, and the consequences of heart failure. The disease is characterized by an inappropriate myocardial hypertrophy, often asymmetrical, and occurs with no obvious inciting hypertrophy stimulus. Hypertrophy can occur in any region of the left ventricle but frequently involves the interventricular septum, which sometimes results in an obstruction of flow through the left ventricular outflow tract (LVOT). At histology, myocardial disarray and islands of fibrosis are considered hallmarks of this disease. The systolic function of LV is preserved until the end-stage of the disease, but the thickened myocardium with fibrosis increases the stiffness of LV chamber causing impaired diastolic relaxation which produces atrial enlargement and may promote atrial fibrillation. At the end stage, the loss of myocites, replaced by gross scar, is sufficient to determine a manifest systolic LV dysfunction. Myocardial scars create a potentially arrhythmogenic substrate and may increase susceptibility to ventricular tachycardias/fibrillation. Indeed, gross macroscopic scarring is frequently present on post-mortem examination in HCM patients who died suddenly, suggesting a possible causal association between fibrosis and malignant arrhythmias. In most patients with HCM, dense focal myocardial fibrosis can also be visualized noninvasively with the use of gadolinium-enhanced cardiac magnetic resonance imaging (LGE-CMR). Recently, some studies demonstrated the prognostic role of fibrosis, expressed as late gadolinium enhancement (LGE), as predictor of myocardial death. In addiction is also possible to quantify extent of LGE in the myocardium of these patients. The diagnosis of HCM is usually performed at relatively young age when not significant stenosis are present in the main coronary arteries. Despite this, many studies showed the importance of myocardial ischemia, probably also due to microvascular disease, as cause of myocardial fibrosis and symptoms and as a trigger of ventricular arrhythmias. Infact the assessment of myocardial ischemia in selected patients with HCM (with preserved LV function) may represent a prognostic tool for identifying those patients at risk for profound disease progression. CMR also allows to evaluate myocardial perfusion and quantify non invasively myocardial blood flow. It’s now clear the importance to study both and individually myocardial fibrosis and ischemia, and to evaluate the relationship between myocardial scar, myocardial blood flow and clinical expression of the disease
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
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