Randomized controlled comparison of antitachycardia pacing algorithms for termination of ventricular tachycardia

AbstractObjectives. This study compared the efficacy and safety of two antitachycardia pacing algorithms in the treatment of ventricular tachycardia.Background. There is agreement that antitachycardia pacing should be adapted to tachycardia rate and be delivered in a burst, but the ideal pacing pattern is not well understood. Effective antitachycardia pacing burst patterns include those with a between-burst decrement (SCAN) with or without an additional within-burst decrement (RAMP).Methods. Prospective randomized crossover comparison of two antitachycardia pacing algorithms (RAMP vs. SCAN) on identical induced sustained ventricular tachycardias was performed.Results. Sixty-five ventricular tachycardias (mean cycle length 364 ± 74 ms) from 37 invasive studies performed in 29 patients were studied; 86% of patients had coronary artery disease and 72% were receiving antiarrhythmic therapy at the time of study. Of the 65 tachycardias, 40 were identical pairs and 25 were unpaired (including 8 with a >30-ms difference in cycle length of induced ventricular tachycardia pairs). In the paired pacing trials, conversion to sinus rhythm occurred, respectively, in 85% of SCAN versus 90% of RAMP protocols (p = 0.63, power = 93%) and within 1.4 ± 0.7 versus 1.7 ± 1.1 attempts (p = 0.41). Discordance for pacing success was seen in taree paris. In unpaired trials, conversion to sinus rhythm occurred in 73% and 57%, respectively (p = 0.68, power = 88%). Tachycardia acceleration during pacing occurred in 7 (11%) of 65 attempts (5 SCAN, 2 RAMP). Acceleration in unpaired ventricular tachycardia trials was correlated with tachycardia cycle length. Failure to convert ventricular tachycardia was associated with a shorter tachycardia cycle length (p < 0.05).Conclusions. In the patients studied, adaptive antiachysardia pacing was safe and effective and, when successful, occurred within three attempts of an 8-beat adaptive barst algorithm. Changes in burst pattern did not affect pacing safety or efficacy. Antitachycardia pacing success was dependent on induced ventricular tachycardia cycle length

Taking the lead: learners’ experiences across the disciplines

The first year at university is a time of significant flux for students, as they adjust to unfamiliar environments, encounter new approaches to teaching and develop fresh learning strategies on the road to becoming self-directed learners. This sense of uncertainty may be compounded by the need to interact with unfamiliar and frequently complex online systems and technologies, possibly even before arrival. Furthermore, although technology is embedded seamlessly into the personal lives of many of today’s students, recent reports have questioned the widespread assumption that young adults have the sophisticated information skills and digital literacy needed to become autonomous learners. In this paper we present findings from a recently-completed study addressing these important issues. We investigated the utilisation of ICT and learning technologies by first-year undergraduates from a variety of different entry routes and academic disciplines, including Physics, Divinity and Veterinary Medicine, at the University of Edinburgh. The focus of the work was on the impact of technology on students’ transition to university and how this changed as they progressed through their first year. The overall shape of the research was based on a student-centred approach, with students’ own views and opinions placed central to the study; and used a holistic approach in which students’ use of e-learning and technology was set within the context of their learning experiences as a whole. To capture the breadth and complexity of their experiences we used a mixed-mode approach, including a series of reflective diaries recorded by learners (in video, audio or text format) together with surveys and focus groups. Students do not form a homogenous group, and findings in this area are inevitably complex. They have high expectations and are generally confident with technology; however, they may not always recognise technology’s potential to support and enhance learning. The term e-learning does not mean much to them; there is simply learning with strands of technology running through. This is reflected in a strong desire for face-to-face contact, with technology used to supplement and enhance this. Students are social, with informal group learning often facilitated by technology. They find their comfort zones and ways of working that are personal to them, and use technology to suit their own way of learning

How Design of Online Learning Materials can Accommodate the Heterogeneity in Student Abilities, Aptitudes and Aspirations

We describe the challenges facing higher education in terms of the heterogeneity of the cohort of students that arrive at university. The reasons why such diversity exists are many: students differ widely in terms of their preparedness for study at university, their degree choice aspirations and the issue of motivation for study of a particular subject. We illustrate how well-designed e-learning course materials can support many of the particular facets of heterogeneity by offering an inherently non-linear pathway through a collection of materials, so as to offer a degree of personalisation of the learning experience.\ud Drawing on our own experience of several years’ development of extensive online materials to support the traditional teaching methods of a large first year physics course at the University of Edinburgh, we highlight three aspects of the design of e-learning materials that facilitate this personalisation. These are: a highly granular source of individual learning objects; online constructions (‘one-downs’ and ‘popups’) that provide additional depth and breadth of material; and the ability to import external resources adapted to the local context

Radiation risk predictions for Space Station Freedom orbits

Risk assessment calculations are presented for the preliminary proposed solar minimum and solar maximum orbits for Space Station Freedom (SSF). Integral linear energy transfer (LET) fluence spectra are calculated for the trapped proton and GCR environments. Organ dose calculations are discussed using the computerized anatomical man model. The cellular track model of Katz is applied to calculate cell survival, transformation, and mutation rates for various aluminum shields. Comparisons between relative biological effectiveness (RBE) and quality factor (QF) values for SSF orbits are made

How well are Australian infants and children aged 4 to 5 years doing?

This report presents an analysis of the data from the first wave of the Longitudinal Study of Australian Children (LSAC) to explore the wellbeing of over 10,000 Australian infants and children. This report presents an analysis of the data from the first wave of the Longitudinal Study of Australian Children (LSAC) to explore the wellbeing of 5,107 children in the infant cohort of the study and the 4,983 children, aged 4 to 5 years, in the child cohort. Wave 1 of LSAC includes measures of multiple aspects of children\u27s early development. These developmental measures are summarised in the LSAC Outcome Index, a composite measure which includes an overall index as well as three separate domain scores, tapping physical development, social and emotional functioning, and learning and cognitive development. This report explores five specific aspects of infants\u27 and children\u27s experiences, exposures and environments in relation to their Outcome Index scores: * key sociodemographic characteristics covering the child, mother, family and neighbourhood * non-parental care experiences * child health—prenatal and postnatal experiences and exposures * maternal physical and mental health * the early educational experiences of the child cohort in the home and out-of-home contexts. This paper is by Melissa Wake, Ann Sanson, Donna Berthelsen, Pollyanna Hardy, Sebastian Misson, Katherine Smith, Judy Ungerer and the LSAC Research Consortium

Microglia-synapse engulfment via PtdSer-TREM2 ameliorates neuronal hyperactivity in Alzheimer's disease models

Neuronal hyperactivity is a key feature of early stages of Alzheimer's disease (AD). Genetic studies in AD support that microglia act as potential cellular drivers of disease risk, but the molecular determinants of microglia-synapse engulfment associated with neuronal hyperactivity in AD are unclear. Here, using super-resolution microscopy, 3D-live imaging of co-cultures, and in vivo imaging of lipids in genetic models, we found that spines become hyperactive upon Aβ oligomer stimulation and externalize phosphatidylserine (ePtdSer), a canonical "eat-me" signal. These apoptotic-like spines are targeted by microglia for engulfment via TREM2 leading to amelioration of Aβ oligomer-induced synaptic hyperactivity. We also show the in vivo relevance of ePtdSer-TREM2 signaling in microglia-synapse engulfment in the hAPP NL-F knock-in mouse model of AD. Higher levels of apoptotic-like synapses in mice as well as humans that carry TREM2 loss-of-function variants were also observed. Our work supports that microglia remove hyperactive ePtdSer+ synapses in Aβ-relevant context and suggest a potential beneficial role for microglia in the earliest stages of AD