1,720,974 research outputs found
Asystole on loop recorder in patients with unexplained syncope and negative tilt testing: age distribution and clinical predictors
No full textBackground Approximately 50% of patients with unexplained syncope and negative head-up tilt test (HUTT) who have an electrocardiogram (ECG) documentation of spontaneous syncope during implantable loop recorder (ILR) show an asystolic pause at the time of the event. Objective The aim of the study was to evaluate the age distribution and clinical predictors of asystolic syncope detected by ILR in patients with unexplained syncope and negative HUTT. Methods This research employed a retrospective, single-center study of consecutive patients. The ILR-documented spontaneous syncope was classified according to the International Study on Syncope of Uncertain Etiology (ISSUE) classification. Results Among 113 patients (54.0 +/- 19.6 years; 46% male), 49 had an ECG-documented recurrence of syncope during the observation period and 28 of these later (24.8%, corresponding to 57.1% of the patients with a diagnostic event) had a diagnosis of asystolic syncope at ILR: type 1A was present in 24 (85.7%), type 1B in 1 (3.6%), and type 1C in 3 (10.7%) patients. The age distribution of asystolic syncope was bimodal, with a peak at age < 19 years and a second peak at the age of 60-79 years. At Cox multivariable analysis, syncope without prodromes (OR 3.7; p = 0.0008) and use of beta blockers (OR 3.2; p = 0.002) were independently associated to ILR-detected asystole. Conclusions In patients with unexplained syncope and negative HUTT, the age distribution of asystolic syncope detected by ILR is bimodal, suggesting a different mechanism responsible for asystole in both younger and older patients. The absence of prodromes and the use of beta blockers are independent predictors of ILR-detected asystole
Temporal relationship between haemodynamic changes and activation of closed-loop stimulation during a tilt-induced vasovagal syncope
No full textAims A dual-chamber pacemaker with closed-loop stimulation (CLS) mode is effective in reducing syncopal recurrences in patients with asystolic vasovagal syncope (VVS). In this study, we explored the haemodynamic and temporal relationship of CLS during a tilt-induced vasovagal reflex.Methods and results Twenty patients underwent a tilt test under video recording 3.9 years after CLS pacemaker implantation. Three patients were excluded from the analysis because of no VVS induced by the tilt test (n = 1) and protocol violation (n = 2). In 14 of the remaining 17 patients, CLS pacing emerged during the pre-syncopal phase of circulatory instability when the mean intrinsic heart rate (HR) was 88 +/- 12 b.p.m. and systolic blood pressure (SBP) was 108 +/- 19 mmHg. The CLS pacing rate thereafter rapidly increased to 105 +/- 14 b.p.m. within a median of 0.1 min [inter-quartile range (IQR), 0.1-0.7 min] when the SBP was 99 +/- 21 mmHg. At the time of maximum vasovagal effect (syncope or pre-syncope), SBP was 63 +/- 17 mmHg and the CLS rate was 95 +/- 13 b.p.m. The onset of CLS pacing was 1.7 min (IQR, 1.5-3.4) before syncope or lowest SBP. The total duration of CLS pacing was 5.0 min (IQR, 3.3-8.3). Closed-loop stimulation pacing was not observed in three patients who had a similar SBP decrease from 142 +/- 22 mmHg at baseline to 69 +/- 4 mmHg at the time of maximum vasovagal effect, but there was no significant increase in HR (59 +/- 1 b.p.m.).Conclusion The reproducibility of a vasovagal reflex was high. High-rate CLS pacing was observed early during the pre-syncopal phase in most patients and persisted, although attenuated, at the time of maximum vasovagal effect.Registration ClinicalTrials.gov identifier: NCT06038708Graphical Abstrac
The triggers of situational syncope do not influence the head-up tilt test response and prognosis
No full textAims The study evaluated the positivity rate, haemodynamic responses, and prognosis in terms of syncopal recurrence among patients with situational syncope (SS) stratified according to the underlying situational triggers.Methods and results We retrospectively evaluated all consecutive patients with SS who underwent nitroglycerine (NTG)-potentiated head-up tilt test (HUTT) at Syncope Unit of the University of Campania 'Luigi Vanvitelli'-Monaldi Hospital from 1 March 2017 to 1 May 2023. All patients were followed for at least one year. The study population was divided according to the underlying triggers (micturition, swallow, defaecation, cough/sneeze, post-exercise). Two hundred thirty-six SS patients (mean age 50 +/- 19.3 years; male 63.1%) were enrolled; among them, the situational trigger was micturition in 109 patients (46.2%); swallow in 32 (13.6%) patients; defaecation in 35 (14.8%) patients; post-exercise in 41 (17.4%) patients; and cough/sneeze in 17 (7.2%) patients. There were no significant differences in baseline clinical characteristics and HUTT responses between different situational triggers. The Kaplan-Meier analysis did not show a statistically different rate of syncope recurrence across patients stratified by baseline situational triggers (log-rank P = 0.21).Conclusion Situational syncope appears to be a homogenous syndrome, and different triggers do not impact the HUTT response or syncope recurrence at 1 year
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
Syncopal Recurrence in Patients Treated With Dual Chamber Pacemaker for Reflex Syncope With Asystole
No full textClinical features and response at head-up tilt test of patients with situational syncope
No full textObjectiveThe study compared clinical characteristics and response at head-up tilt test (HUTT) between situational (SS) and vasovagal syncope (VVS). MethodsConsecutive patients who underwent nitroglycerin-potentiated HUTT were retrospectively dichotomised into two groups: those with a history of SS and those with a history of VVS. The patients with SS were further subdivided into patients with SS alone and with SS and at least one episode of VVS. Results1285 patients were enrolled: 246 (19.1%) had SS (SS alone in 121 and SS+VVS in 125). Patients with SS were older (48.8 & PLUSMN;20.0 vs 44.4 & PLUSMN;19.1, p=0.007) and more frequently male (57.3% vs 47.7%, p=0.001). At multivariable analysis, smoking habit (OR 2.28; p<0.0001), history of traumatic syncope (OR 2.29; p=0.0001) and ACE inhibitors/angiotensin II receptor blockers (OR 4.74; p<0.0001) were independently associated with SS. HUTT was positive in 175 (71.1%) patients with SS and in 737 (70.9%) patients with VVS (p=0.9). Patients with SS showed more mixed (42.3% vs 32.0%, p=0.002) and vasodepressor forms (10.6% vs 6.1%, p=0.01) and less cardioinhibitory responses compared with others (18.3% vs 32.8%, p<0.0001). ConclusionsCompared with VVS, patients with SS have different clinical characteristics and a higher prevalence of hypotensive drugs leading to hypotensive susceptibility. The positivity rate of HUTT is high and similar to that of VVS, although patients with SS show a higher prevalence of hypotensive responses
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