1,721,068 research outputs found
Pilot study on the separability of the native heart sounds and device support noise in patients implanted with left ventricular assist devices
Full text linkThe assessment of heart sounds in patients with Left Ventricular Assist Devices (LVADs) presents significant challenges. The persistent mechanical hum produced by the pump obscures the natural heart sounds, complicating the detection of critical issues such as valve dysfunction, suction events, and abnormal blood flow patterns. Currently, echocardiography is frequently employed for monitoring; however, its application is not practical for home environments. This study explores the potential of phonocardiography (PCG) as a non-invasive method for monitoring cardiac function in patients with LVADs, specifically by accurately estimating cardiac time intervals (CTIs). PCG signals were collected from patients equipped with the HM3 LVAD, AbbottTM. We employed Power Spectral Density (PSD) and Time-Frequency (TF) analysis to identify the dominant frequency components produced by the pump and their respective timings. A template-matching technique was applied to isolate the pulsatility mode of the LVAD from the PCG, thereby enabling the detection of native heart sounds. From this refined signal, we extracted the closure times of the heart valves. Our approach successfully differentiated native heart sounds from the in-band noise generated by the device, demonstrating the efficacy of PCG in LVAD patients. The identified CTIs provide important insights into the heart's compensatory mechanisms under these conditions and hold promise for continuous, non-invasive cardiac monitoring. This study presents the significant potential of PCG as an alternative to echocardiography for evaluating cardiac health in LVAD patients. Future research should focus on refining automated detection algorithms and validating this technique across larger patient populations to enhance its feasibility for monitoring in home settings.Clinical Relevance- This study provides clinicians with a non-invasive method to assess cardiac function in LVAD patients, overcoming issues from pump noise. Phonocardiography helps detecting complications early and reduces reliance on echocardiography, allowing for easier home monitoring and improved patient management
Temporal trends in procedural death and need for urgent open surgery during transcatheter aortic valve replacement: A single, high-volume center 10-year experience
No full textBACKGROUND: Despite advancements in the safety of transcatheter aortic valve replacement (TAVR) resulting in progressively wider indications, adverse periprocedural outcomes still raise concern. Real-world outcome data are thus of primary importance to evaluate the procedural risk-benefit trade-off in the continuously changing populations undergoing TAVR.METHODS: We retrospectively assessed 1348 consecutive patients undergoing TAVR between 2007 and 2017. The primary endpoint was a composite of procedural mortality and need for conversion to emergent surgery, as defined by the Valve Academic Research Consortium-2 criteria. Temporal trends in baseline characteristics and outcomes were evaluated. The independent outcomes predictors were assessed through multivariate regression analysis.RESULTS: A total of 56 (4.1%) patients experienced the primary endpoint. 47 (3.5%) patients died during hospital stay, 19 (1.4%) within 72 h from the procedure. 17 patients (1.2%) needed an emergent conversion to open surgery, of whom 7 (41.2%) did not survive. Significant temporal trends of increasing mean age (from 79.4 ± 7.4 to 81 ± 7.5, p = 0.007) and decreasing surgical risk (mean STS: from 9 ± 9.5 to 7.1 ± 9.8, p = 0.010) were observed. When dichotomized at the median procedural date (year 2014), a significant reduction in the occurrence of the primary endpoint in more recent years was observed (3.0% vs 5.2%, p = 0.041). This was the single primary endpoint independent predictor at multivariate analysis.CONCLUSION: The high-volume 10-year experience in TAVR procedures at our center shows encouraging trends in procedural mortality reduction, which anyhow still occurs at a non-negligible rate, calling for further research to detect and to blunt the determinant of early procedural events
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
Left ventricular unloading and venting in veno‐arterial extracorporeal membrane oxygenation: the importance of cardiogenic shock aetiology in guiding treatment strategies
Full text linkInhibitors of the Interleukin-1 Receptor Accessory Protein Signaling: Another Asset in the Cardio-Immunology Toolbox
No full textDispelling 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
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