The U wave in atrial fibrillation

The U wave in ECGs of patients is difficult to observe because it is hidden under the atrial fibrillatory wave. Measurement and characteristics of the U wave in atrial fibrillation have not previously been described. Beat averaging was used to reveal the U waves in 12-lead ECGs of 8 patients with atrial fibrillation taking account of heart rate dependency of U wave characteristics. U wave polarity and amplitude in 12-lead ECG and the amplitude ratio of U wave to atrial fibrillatory wave in lead VI were measured. U waves were measureable in all patients. U waves were predominantly positive in leads 1. 11. aVF. V2. V3, V4, V5 and V6, negative in leads aVR. Amplitudes were largest in the precordial leads measuring up to 55 fJ V. In lead VI the U wave amplitude was on average 0.17 (range 0.1 to 0.4) times the amplitude of the atrial fibrillatory wave. U waves can be measured by ventricular beat averaging in AF patients. U waves were normal in this small group of patients

Universities, Community Engagement, and Democratic Social Science

The purpose of this dissertation is to identify and compare differences between institutional conceptualizations of community engagement with the understanding and practices of faculty engaged in community-based research (CBR), and analyze the implications of these differences. The study contrasts the model of community engagement that is being promoted by universities and the granting agencies (specifically the Social Sciences and Humanities Research Council of Canada) with what community-engaged researchers experience it to be, with a view to developing an analysis of the relationship between individuals and the political economy of research in which they work. In Canada, universities are being encouraged by the federal government to assume greater responsibility for economic development and to translate knowledge into products and services for the market—while at the same time being tasked to work with communities in alleviating the social and economic excesses of the market. Drawing upon a qualitative, interview-based research design, my main line of argument is that there is a contradiction regarding the democratization of knowledge production between universities and communities that the institutionalization of community engagement promises—and the aligning of this process of knowledge production with market-driven forces and outcomes. The concern addressed in the dissertation is that the emancipatory intentions of community-based research are being co-opted by the entrepreneurial and managerial ethos influencing and structuring the "doing" of research. Such developments necessitate an interrogation of the institutional contexts in which participatory and community-engaged research are becoming positioned within the market-driven and performance-based governance of university research

Non-invasive estimation of left atrial dominant frequency in atrial fibrillation from different electrode sites: Insight from body surface potential mapping

© 2014, CardioFront LLC. All rights reserved. The dominant driving sources of atrial fibrillation are often found in the left atrium, but the expression of left atrial activation on the body surface is poorly understood. Using body surface potential mapping and simultaneous invasive measurements of left atrial activation our aim was to describe the expression of the left atrial dominant fibrillation frequency across the body surface. 20 patients in atrial fibrillation were studied. The spatial distributions of the dominant atrial fibrillation frequency across anterior and posterior sites on the body surface were quantified. Their relationship with invasive left atrial dominant fibrillation frequency was assessed by linear regression analysis, and the coefficient of determination was calculated for each body surface site. The correlation between intracardiac and body surface dominant frequency was significantly higher with posterior compared with anterior sites (coefficient of determination 67±8% vs 48±2%,

Effect of catheter ablation on quality of life in patients with atrial fibrillation and its correlation with arrhythmia outcome

Objective To assess the effect of catheter ablation on atrial fibrillation (AF) symptoms and quality of life (QoL). Methods Patients with AF scheduled for ablation were recruited. Pulmonary vein isolation (PVI) was performed and complex fractionated atrial electrogram (CFAE)±linear ablation undertaken in patients in AF despite PVI. QoL and AF symptoms were assessed using SF-36 V2 and Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaires before and 3 months after ablation. Change in QoL scores after ablation was correlated with clinical parameters and the extent of ablation. Magnitude of QoL change was compared between AFEQT and SF-36 physical component summary (PCS) and mental component summary (MCS) scores and correlated with arrhythmia outcome. Results 80 patients were studied. Summative and individual health scores for both AFEQT (51.5±22.0 vs 81.3±18.2; p<0.01) and SF-36 (PCS 43.3±10.5 vs 47.9±11.3; p<0.01 and MCS 45.0±11.5 vs 51.5±9.4; p<0.01) improved significantly in patients who maintained sinus rhythm after ablation, but not in those with recurrent AF. Improvement in AFEQT (25.4±19) was significantly greater than change in PCS (6.8±6.4; p<0.01) and MCS (8.5±7.9; p<0.01) scores and correlated more closely with arrhythmia outcome (AFEQT r=0.55; PCS r=0.26; MCS r=0.30). Conclusions Patients who maintained sinus rhythm after ablation had a significant improvement in AF symptoms and QoL; however, no improvement was observed in patients with recurrent AF. QoL change after ablation did not correlate with baseline clinical parameters or ablation strategy. AF specific QoL scales are more responsive to change and correlate better with ablation outcome

Principal component analysis of atrial fibrillation: Inclusion of posterior ECG leads does not improve correlation with left atrial activity

Background Lead V? is routinely analysed due to its large amplitude AF waveform. V? correlates strongly with right atrial activity but only moderately with left atrial activity. Posterior lead V? correlates strongest with left atrial activity. Aims (1) To establish whether surface dominant AF frequency (DAF) calculated using principal component analysis (PCA) of a modified 12-lead ECG (including posterior leads) has a stronger correlation with left atrial activity compared to the standard ECG. (2) To assess the contribution of individual ECG leads to the AF principal component in both ECG configurations. Methods Patients were assigned to modified or standard ECG groups. In the modified ECG, posterior leads V? and V? replaced V? and V?. AF waveform was extracted from one-minute surface ECG recordings using PCA. Surface DAF was correlated with intracardiac DAF from the high right atrium (HRA), coronary sinus (CS) and pulmonary veins (PVs). Results 96 patients were studied. Surface DAF from the modified ECG did not have a stronger correlation with left atrial activity compared to the standard ECG. Both ECG configurations correlated strongly with HRA, CS and right PVs but only moderately with left PVs. V? contributed most to the AF principal component in both ECG configurations

Performance Evaluation of State of the Art Systems for Physical Activity Classification of Older Subjects Using Inertial Sensors in a Real Life Scenario: A Benchmark Study

The popularity of using wearable inertial sensors for physical activity classification has dramatically increased in the last decade due to their versatility, low form factor, and low power requirements. Consequently, various systems have been developed to automatically classify daily life activities. However, the scope and implementation of such systems is limited to laboratory-based investigations. Furthermore, these systems are not directly comparable, due to the large diversity in their design (e.g., number of sensors, placement of sensors, data collection environments, data processing techniques, features set, classifiers, cross-validation methods). Hence, the aim of this study is to propose a fair and unbiased benchmark for the field-based validation of three existing systems, highlighting the gap between laboratory and real-life conditions. For this purpose, three representative state-of-the-art systems are chosen and implemented to classify the physical activities of twenty older subjects (76.4 \ub1 5.6 years). The performance in classifying four basic activities of daily life (sitting, standing, walking, and lying) is analyzed in controlled and free living conditions. To observe the performance of laboratory-based systems in field-based conditions, we trained the activity classification systems using data recorded in a laboratory environment and tested them in real-life conditions in the field. The findings show that the performance of all systems trained with data in the laboratory setting highly deteriorates when tested in real-life conditions, thus highlighting the need to train and test the classification systems in the real-life setting. Moreover, we tested the sensitivity of chosen systems to window size (from 1 s to 10 s) suggesting that overall accuracy decreases with increasing window size. Finally, to evaluate the impact of the number of sensors on the performance, chosen systems are modified considering only the sensing unit worn at the lower back. The results, similarly to the multi-sensor setup, indicate substantial degradation of the performance when laboratory-trained systems are tested in the real-life setting. This degradation is higher than in the multi-sensor setup. Still, the performance provided by the single-sensor approach, when trained and tested with real data, can be acceptable (with an accuracy above 80%)

Becoming European? Constructing Identity in Urban Regeneration Discourse in Ireland

Drawing upon policy documents and interview data, this article critically assesses how the conservation, interpretation and promotion of built heritage is used as a categorical identity referent within urban regeneration discourse in Ireland. The paper is critical of two inter-related dynamics. First, it addresses the relation between culture-led urban regeneration and the construction of a sense of place. Second, it problematizes parallel attempts to constitute a sanitized and marketable urbanism expressed via a rhetorical and contrived veneer of European identity. A fundamental premise of the discussion is that the challenge of articulating a coherent and distinctive sense of urban cultural identity has become an issue of problematic salience in the context of European regional cities — not only between various cities, but also within such cities themselves. In particular, the discussion is intended to provide empirical evidence of how a regional municipality utilizes efforts to preserve the built environment and claims about local heritage in order to encourage tourism and economic regeneration. It is argued that the contextualizing of local planning discourse within European policy initiatives serves to legitimate the vision of renewal being proposed. Utilizing discourse analysis assists in displaying how policy architects exert a normalizing view of urban redevelopment, the conclusion is drawn that regeneration discourse is operationalized with the imperative of sustaining economic viability, one in which the existent built heritage of the city acquires the ascription of functional commodity held amidst the marketplace of European cities

Heterogeneity of rural consumer perceptions of health service access across four regions of Victoria

Access to a range of services, including healthcare, ranks among the key determinants of health and wellbeing. It varies with both health system supply factors and consumer demand characteristics. For rural populations, access to health services can be..

“Teaching is a learning experience”:: Exploring Faculty Engagement with Low-Income Adult Learners in a College-Community Partnership Program

This article examines interview data with faculty teaching in a college-community partnership program for low-income adult students in an urban setting. The purpose of the study was to explore faculty understandings of the diverse learning needs of their students and the perceptions they have of the efficacy of their teaching practices regarding course design and delivery. Findings highlight the central dynamic of teaching as a negotiated relationship and process of mutual learning between faculty and students, and the means by which faculty work to create engaging and empowering classroom environments. Our research is relevant to educators interested in designing and delivering courses from a social justice perspective in order to encourage adults from low-income communities to pursue a post-secondary pathway. Keywords: post-secondary access, adult learners, low-income student engagement, socialjustice educationLe présent article examine des données d’entrevues réalisées avec le corps professoral dans le cadre d’un programme de partenariat collège-communauté à l’intention d’étudiants adultes à faible revenu en milieu urbain. L’étude avait pour but d’explorer la façon dont le corps professoral comprend les divers besoins en apprentissage de ses étudiants et la façon dont il perçoit l’efficacité de ses pratiques d’enseignement en ce qui a trait à la conception et à l’offre des cours. Les résultats font ressortir la dynamique centrale de l’enseignement en tant que relation négociée et comme processus d’apprentissage mutuel entre le corps professoral et les étudiants, et les moyens par lesquels le corps professoral s’emploie à créer des environnements de salle de classe captivants et stimulants. Notre recherche s’avère pertinente pour les éducateurs qui souhaitent concevoir et offrir des cours dans une perspective de justice sociale afin d’encourager les adultes issus des communautés à faible revenu à poursuivre des études postsecondaires. Mots-clés : accès aux études postsecondaires, apprenants adultes, faible revenu, engagementdes étudiants, éducation à la justice social