1,721,656 research outputs found
A New Paradigm in Cardiac Resynchronization Therapy?
No full textWe thank Polasek et al for the opportunity to clarify some crucial points of our study.1 First, our study is obser- vational and retrospective, thus needing further confirmation by prospective ad hoc studies as stated in the report. Obvi- ously, given the retrospective and observational nature of the study, a con- trol group cannot be expected unless we performed cardiac resynchronization therapy (CRT) device implantation dis- regarding the guidelines and it is not our case. Accordingly, we just commented on reported results, but we did not discourage CRT implantation in these patients. Second, the hypothesis gener- ated by our data was the existence of an upper cut-off value of QRS duration above which CRT is less effective because of extensive electrical and structural remodeling. Our observations are consistent with findings that showed a worse clinical outcome and prognosis related to either left bundle branch block morphology or prolonged QRS duration in patients with heart failure.2,3 A recent large prospective observational study, totaling 3,319 patients with CRT, showed that cardiac mortality was highest at the upper extremes of QRS duration.4 Moreover, a subanalysis of the Resynchronization Reverses. Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) trial showed a linear reduction of left ventricular vol- umes after CRT as the QRS duration in- creases from 120 to 180 ms, followed by a declining efficacy from 180 ms on- ward.5 Third, it is important to underline that we described and commented the results of meta-analysis as usually is done in the discussion section.6 Further- more, we deliberately chose to comment on the graph showing the combined end point of death and hospitalization for heart failure, rather than death only, because this is more representative of the efficacy of CRT given the well- established deleterious economic and clinical impact of hospitalization for worsening heart failure.7,8 Finally, we would advise Polasek et al that it is hard to discuss unpublished results and compare them with others using different end points: a less validated end point (!10% reduction of the left ventricular end-systolic diameter) in Polasek data and a well-established end point (!15% reduction of the left ventricular end- systolic volume) in our study
Volume preserving non-homogeneous mean curvature flow in hyperbolic space
No full textWe study a volume/area preserving curvature flow of hypersurfaces that are convex by horospheres in the hyperbolic space, with velocity given by a generic positive, increasing function of the mean curvature, not necessarily homogeneous. For this class of speeds we prove the exponential convergence to a geodesic sphere. The proof is inspired by [9] and is based on the preserving of the convexity by horospheres that allows to bound the inner and outer radii and to give uniform bounds on the curvature by maximum principle arguments. In order to deduce the exponential trend, we study the behaviour of a suitable ratio associated to the hypersurface that converges exponentially in time to the value associated to a geodesic sphere
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
Transvenous cardioverter-defibrillator implantation in a patient with tricuspid mechanical prosthesis
No full textBackground. A 64-year-old woman was referred to our center because of poorly tolerated ventricular tachycardia (VT) at 210 bpm due to an old myocardial infarction. The patient had been operated on at age of 20 for mitral valve commissurolysis, at age of 49 for ductal carcinoma, at age of 56 for mitral valve replacement, and at age of 61 for tricuspid valve replacement. Left ventricular EF was 31%. The patient was in permanent atrial fibrillation (AF) since the age of 53. She had undergone three cardiac surgery procedures, ending with two prosthetic mechanical valves. The cardiac surgery team advised against an epicardial ICD implantation. Results. We achieved a fully transvenous implant, with a screw-in defibrillation coil in the low right atrium and a bipolar pacing/sensing lead in a posterolateral branch of the coronary sinus. Pacing/sensing parameters were reliable, and effective defibrillation occurred at 20 J by a stepdown protocol. During 16-month follow-up, three VT episodes at 210 bpm were terminated by antitachycardia pacing (ATP) therapy. Left ventricular pacing/sensing was stable at long term. Conclusion. Thanks to technologic improvements, transvenous ICD implantation is feasible and safe in patients with a tricuspid mechanical prosthesi
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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