1,720,986 research outputs found
Is amiodarone safe in heart failure?
No full textHeart failure is a complex clinical syndrome that
may lead to sudden cardiac death. Several trials
have studied whether the antiarrhythmic agent
amiodarone reduces such mortality in heart failure,1 and
two trials in particular have been at the centre of the
debate: GESICA and CHF-STAT. It is important to remember past negative
experiences with antiarrhythmic agents as well as the
recent discontinuation of the ANDROMEDA trial
owing to greater mortality associated with use of dronedarone,
a non-iodinated derivative of amiodarone, in
patients affected by left ventricular ventricular dysfuntion.
On the basis of all of these considerations we
believe that a further large scale, prospective trial is
warranted to evaluate the safety of amiodarone in
heart failure
ABO blood group alleles: a risk factor for coronary artery disease. An angiographic study
No full textOBJECTIVES: To analyze the impact of ABO groups on coronary heart disease risk factors, coronary involvement and prognosis. METHODS: An observational single center study was conducted to examine 4901 consecutive patients with heart disease receiving coronary angiography and ABO group determination at National Research Council Institute of Clinical Physiology between January 1993 and December 2003, with maximum 10 years follow-up. All-cause death and cardiac death, were the considered end points. RESULTS: When compared to the official distribution of ABO groups in the Italian population (O 40%, A 36%, B 17%, AB 7%), a substantially different distribution was observed in the study population (O 43.3%, A 41.4%, B 11.2%, AB 4.1%). In addition, a significant association was found between group non-O and family history of ischemic heart disease, hypercholesterolemia and presence of coronary atherosclerosis. Higher prevalence of A and B alleles was found in patients with myocardial infarction (P<0.05). Group non-O was a powerful predictor of cardiac mortality in patients aged <65 years, particularly in women (HR 1.53, 95% CI 1.06-2.21 and HR 5.29, 95% CI 1.57-17.82, respectively). CONCLUSIONS: Group non-O is associated with increased mortality in patients with ischemic heart disease. Group non-O increases the risk for cardiac death in non-elderly patients, particularly in younger females, and groups A and B prevail in myocardial infarction. ABO group determination might aid in genetic screening for ischemic heart disease and become relevant in the management of risk factor control
Relationships between left ventricular sympathetic innervation and diastolic dysfunction: the role of myocardial innervation/perfusion mismatch
No full textBackground: A possible relationship between cardiac sympathetic denervation and left ventricular (LV) diastolic dysfunction has been suggested. However, an evaluation of the interactions between myocardial adrenergic tone and LV perfusion and diastolic function is lacking. Methods and results: Seventy-two patients underwent 99mTc-tetrofosmin/123I-metaiodobenzylguanidine (123I-MIBG) cardiac Cadmium-Zinc-Telluride (CZT) imaging. The summed rest score (SRS) and summed 123I-MIBG score (SS-MIBG) were computed as measures of regional perfusion and innervation heterogeneities. LV segments showing an impaired innervation, despite a relatively preserved perfusion (99mTc-tetrofosmin-123I-MIBG tracers’ uptake ≥25%), were individuated (innervation/perfusion mismatch). The peak filling rate (PFR) was computed as a measure of LV diastolic function. Nineteen of the 72 (26%) patients presented a normal LV diastolic function, while 29 (40%) and 24 (34%) had a mild and overt diastolic dysfunction. Subjects with diastolic dysfunction showed more abnormal SRS and SS-MIBG values (P < 0.001). In the global population, 502/1224 (41%) LV segments showed an innervation/perfusion mismatch. A modest correlation between the extent of cardiac innervation/perfusion mismatch and PFR values was evident (R = −0.27, P = 0.029). On multivariate analysis, the extent of regional innervation/perfusion mismatch remained an independent predictor of overt LV diastolic abnormalities (P = 0.017). Conclusions: The burden of LV regions showing an innervation/perfusion mismatch associates with the occurrence of overt diastolic dysfunction
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
Thyroid hormone, amiodarone therapy, and prognosis in left ventricular systolic dysfunction
No full textBackground: Amiodarone protects patients with left ventricular systolic dysfunction (LVSD) against serious arrhythmias, but it also has numerous side effects on non-cardiac organs, such as the thyroid. Indeed, amiodarone may inhibit the peripheral conversion of T(4) into T(3). Pathologically reduced serum levels of T(3) the so-called "low T(3) syndrome" (LOWT3) - increase mortality in patients with LVSD and not on amiodarone. Aim: The aim of the study was to examine the relationship between thyroid hormone status, amiodarone therapy, and outcome in a population with LVSD. Material/subjects and methods: A total of 2344 patients with LVSD and free of overt hyper- and hypothyroidism were enrolled. The population was divided into 4 groups: group 1 (LOWT3 and amiodarone therapy, no.=126), group 2 (isolated amiodarone therapy, no.=74), group 3 (isolated LOWT3, no.=682), group 4 (controls, no.=1462). Results: Kaplan-Meier curves showed, after a mean follow-up of 31 months, increased total and cardiac mortality in groups 1 (30% and 20%, respectively), 2(23%, 11%), and 3(22%, 12%) compared to group 4 (total mortality log-rank 82.8, p<0.0001; cardiac mortality log-rank 63.1, p<0.0001). At Cox analysis, adjusted for several clinical variables, survival was reduced in groups 1 and 3 compared to group 4. Group 2 had a similar mortality to group 4, although the number of patients was too limited to accurately assess the effect of amiodarone on long-term prognosis. Conclusions: LOWT3 exerts an adverse impact on prognosis in LVSD, which is not influenced by concomitant amiodarone therapy
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