1,720,970 research outputs found
Left ventricular summit premature ventricular contractions treated by venous ethanol infusion: Scar assessment by magnetic resonance imaging
No full textLeft ventricular (LV) summit premature ventricular contractions (PVCs) are often unresponsive to radiofrequency (RF) ablation. Retrograde venous ethanol infusion (RVEI) can be a valuable alternative in this scenario. A 43-year-old woman without structural heart disease presented with LV summit PVCs unresponsive to RF ablation because of their deep-seated origin. Unipolar pace mapping performed through a wire inserted into a branch of the distal great cardiac vein (GCV) demonstrated 12/12 concordance with the clinical PVCs thus indicating close proximity to PVCs’ origin. RVEI abolished the PVCs without complications. Subsequently, magnetic resonance imaging (MRI) evidenced an intramural myocardial scar produced by ethanol ablation. In conclusion, RVEI effectively and safely treated PVC arising from a deep site in the LVS. The scar provoked by chemical damage was well characterized by MRI imaging
Transcatheter aortic valve replacement for aortic regurgitation after septal myectomy in patients with obstructive hypertrophic cardiomyopathy
No full textTransaortic septal myectomy is currently considered to be the most appropriate surgical treatment for patients with obstructive hypertrophic cardiomyopathy (HCM) and heart failure symptoms unresponsive to medical therapy (1). However, a well-described late complication of this approach is the development of a substantial aortic regurgitation (AR), frequently requiring surgical aortic valve replacement (SAVR) (2). Post-myectomy AR may be secondary to the leaflet trauma at the time of surgery since septal myectomy is performed through the aortic valve after aortotomy; secondly, it may be related to the turbulent blood flow in the left ventricle outflow tract after surgery that in turn may cause recurrent trauma to the valve in systole; lastly, septal myectomy involves a piece of myocardium below the right coronary cusp and over time the derangement of septal structure may alter the support of the aortic valve causing gradual distortion of the aortic annulus. A redo SAVR is usually associated with an increased risk profile due to the presence of adherences and comorbidities. Although some studies reported encouraging results (3), TAVR is still an off-label indication for AR
Outer loop and isthmus in ventricular tachycardia circuits: Characteristics and implications
No full textBackground: The isthmus of ventricular tachycardia (VT) circuits has been extensively characterized. Few data exist regarding the contribution of the outer loop (OL) to the VT circuit. Objective: The purpose of this study was to characterize the electrophysiological properties of the OL. Methods: Complete substrate activation mapping during sinus rhythm (SR) and full activation mapping of the VT circuit with high-density mapping were performed. Maps were analyzed mathematically to reconstruct conduction velocities (CVs) within the circuit. CV >100 cm/s was defined as normal and <50 cm/s as slow. Electrograms along the entire circuit were analyzed for fractionation, duration, and amplitude. Results: Six postmyocardial infarction patients were enrolled. The VT circuit was a figure-of-eight reentrant circuit in 4 patients and a single-loop circuit in 2 patients. The OL exhibited a mean of 1.9 ± 0.9 and 1.6 ± 0.5 corridors of slow conduction (SC) during VT and SR, respectively. SC in the OL were longer and faster than SC in the isthmus during SR. At the OL, SC sites showed local abnormal ventricular activity in 92%, and a bipolar voltage <0.5 mV was identified in 80.7%. Of the double-loop circuits, only 1 patient had fixed lines of block as isthmus boundaries, whereas in 3 patients the circuits were at least partially functional. Conclusion: In ischemic reentrant VT circuits, the OL contributes significantly to reentry with multiple corridors of SC. These corridors can result from structural or functional phenomena. Isthmus boundaries may correspond to functional or fixed lines of block
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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