Dissertations / Theses on the topic 'Defibrillation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Defibrillation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Oeding, Matthew. "Defibrillation safety." Thesis, Oeding, Matthew (2012) Defibrillation safety. Other thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/13113/.
Full textMcKeown, Paschal Patrick Joseph. "Transoesophageal cardioversion and defibrillation." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334471.
Full textDarragh, K. M. "Optimisation of Defibrillation for Ventricular Fibrillation." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527675.
Full textHarbinson, Mark Thomas. "Studies in atrial and ventricular defibrillation." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361286.
Full textCaldwell, Jane Cochrane. "Ventricular fibrillation in ischaemia and its defibrillation." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/6196/.
Full textMorgan, Stuart William. "Low-Energy Defibrillation Using Resonant Drift Pacing." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507718.
Full textHuber, Claudia. "Konzeption und Evaluation eines Qualitätsmanagementsystems im Bereich der Frühdefibrillation." kostenfrei, 2008. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1217/.
Full textSantos, JoseÌ Angel. "Transcutaneous pulsed mode power delivery to implants for the treatment of atrial fibrillation." Thesis, University of Ulster, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251911.
Full textWilson, Carol Mildred. "Studies on cardiac defibrillation : waveform, threshold and damage." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357514.
Full textWalsh, S. J. "Biphasic waveforms for internal and external atrial defibrillation." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401795.
Full textPaisey, John R. "Defibrillation, the coronary venous system and the passive electrode affect." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420222.
Full textBennett, J. R. "The transvenous defibrillation of ventricular fibrillation using novel shock waveforms." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534636.
Full textWong, Po-luk, and 王寶綠. "An evidence-based guideline of defibrillation for cardiac arrest patients." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193065.
Full textpublished_or_final_version
Nursing Studies
Master
Master of Nursing
Carlisle, Ewan James Frazer. "Studies on ventricular fibrillation : spectral analysis and optimisation of defibrillation." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317020.
Full textSchönegg, Martin [Verfasser], and A. [Akademischer Betreuer] Bolz. "Impedanzunabhängige Defibrillation mit physiologischer Impulsform / Martin Schönegg. Betreuer: A. Bolz." Karlsruhe : KIT-Bibliothek, 2008. http://d-nb.info/1013805593/34.
Full textJohnston, Paul Weir. "Transthoracic impedence cardiography : a method of detecting the loss of cardiac output during arrhythmias." Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387925.
Full textKemper, Michael [Verfasser], and Bernhard [Akademischer Betreuer] Zwißler. "Antizipatorische Ladesequenz der Defibrillation : Vergleich der No-Flow Zeit und Sicherheit der Defibrillation mit dem ERC- Handlungsablauf : eine prospektive, randomisierte Simulatorstudie / Michael Kemper ; Betreuer: Bernhard Zwißler." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1213658950/34.
Full textUchaipichat, Nopadol. "The prediction of defibrillation outcome using time-frequency power spectrum methods." Thesis, Edinburgh Napier University, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418238.
Full textJorgenson, Dawn Blilie. "Optimizing current delivery in defibrillation : finite element models and experimental validation /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/8054.
Full textDwyer, Trudy, and t. dwyer@cqu edu au. "A shock in time saves lives: Theory of Planned Behaviour and nurse-initiated defibrillation." Central Queensland University. Nursing and Health Studies, 2004. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20050221.152259.
Full textDalzell, Gavin W. N. "Factors involved in synchronised and unsynchronised defibrillation of patients with cardiac disease." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317028.
Full textWong, Tee Wee. "The effects of class III antiarrythmic drugs on fibrillation and defibrillation thresholds." Thesis, The University of Sydney, 1997. https://hdl.handle.net/2123/27524.
Full textHamilton, Andrew James. "The effectiveness and cost-effectiveness of a Northern Ireland public access defibrillation project." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527927.
Full textBernabeu, Llinares Miguel Oscar. "An open source HPC-enabled model of cardiac defibrillation of the human heart." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:9ca44896-8873-4c91-9358-96744e28d187.
Full textOhuchi, Katsuhiro, Yasuhiro Fukui, Ichiro Sakuma, Nitaro Shibata, Haruo Honjo, Setsuo Takatani, and Itsuo Kodama. "Computer Simulation Analysis of Shock Intensity - and Phase - Dependence of High-Intensity DC Stimulation Aftereffects on Action Potential of Ventricular Muscle." Research Institute of Environmental Medicine, Nagoya University, 2003. http://hdl.handle.net/2237/7600.
Full textKim, Seok Chan. "ELECTROPORATION BY STRONG INTERNAL DEFIBRILLATION SHOCK IN INTACT STRUCTURALLY NORMAL AND CHRONICALLY INFARCTED RABBIT HEARTS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1196122659.
Full textArafune, Tatsuhiko, Akira Mishima, Ichiro Sakuma, Hiroshi Inada, Nitaro Shibata, Harumichi Nakagawa, Masatoshi Yamazaki, Haruo Honjo, and Itsuo Kodama. "Virtual Electrode-induced Spiral Reentry in Ventricular Myocardium Perfused in-vitro." Research Institute of Environmental Medicine, Nagoya University, 2003. http://hdl.handle.net/2237/7602.
Full textFotuhi, Parwis. "Tierexperimentelle Untersuchungen zur Therapie und Pathogenese von ventrikulären Herzrhythmusstörungen." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2003. http://dx.doi.org/10.18452/13876.
Full textSudden cardiac death is one of the leading causes of death in Europe, and the leading cause of all natural deaths in the USA. The primary aim of experimental and clinical research is the "prediction and prevention" of lethal ventricular arrhythmias. The focus of this thesis is on animal studies investigating the mechanisms of arrhythmias. Using a novel multichannel electrical cardiac mapping technique we were able to demonstrate that whatever generates fibrillation activations it locates at a small region in the LV apex. This research will widen our understanding of defibrillation and causes of lethal ventricular arrhythmias, but is still only a piece of the puzzle called sudden cardiac death. New initiated or planed project are focusing on arrhythmias in patients and animals with heart failure or acute ischemia. Novel mapping techniques and animal models might further widen our understanding of the mechanisms and might help to develop and improve therapeutic options.
Goulart, Jair Trapé 1987. "Vulnerabilidade de miócitos cardíacos a campos elétricos de alta intensidade = influência da estimulação beta-adrenérgica = The lethal effect of high-intensity electric fields on cardiac myocytes: influence of the beta-adrenergic pathway." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259400.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-20T23:57:01Z (GMT). No. of bitstreams: 1 Goulart_JairTrape_M.pdf: 1965789 bytes, checksum: 94fe3a318201b7addef8365fbeea0f40 (MD5) Previous issue date: 2012
Resumo: A aplicação de campos elétricos de alta intensidade (CEAI) no coração é realizada frequentemente durante tentativas de reversão da fibrilação, e para gerar sincronismo cardíaco com o uso de marca-passos. Entretanto, este procedimento rotineiro pode causar danos ao miocárdio. O objetivo deste trabalho foi investigar se a estimulação ?-adrenérgica afeta a vulnerabilidade de miócitos ventriculares ao CEAI, uma vez que, durante a fibrilação ventricular, há aumento reflexo do tônus simpático, em virtude da consequente hipotensão arterial, e a administração de catecolaminas é um procedimento comum neste tipo de emergência. Miócitos foram isolados do ventrículo esquerdo de ratos Wistar adultos por digestão enzimática. As células foram perfundidas com solução de Tyrode a 23 °C e estimuladas a 0,5 Hz. Aplicou-se CEAI em intensidades crescentes até que fosse induzida uma lesão letal na célula. A probabilidade de morte celular foi determinada em função da amplitude do CEIA e da máxima variação estimada do potencial de membrana (?Vmax) por análise de sobrevivência (curva de letalidade). Destas curvas, obteve-se o parâmetro EL50 (valor de CEAI ou ?Vmax com probabilidade de letalidade de 0,5). A estimulação ?-adrenérgica, pela perfusão com 10 nM de isoproterenol (ISO), foi realizada na ausência e presença de 150 nM de metoprolol (MET, bloqueador de adrenoceptores ?1), 10 ?M de H-89 (inibidor de PKA) e 500 nM de BIS I (inibidor de PKC), bem como após protocolo para minimizar o aumento de mobilização celular de Ca2+. As curvas foram comparadas por teste de Mantel-Cox. O tratamento com ISO promoveu o deslocamento da curva para a direita (p < 0,01) e EL50 aumentou de 85 para 100 V/cm. MET e H-89 aboliram o efeito protetor do ISO, e, quando perfundidos na ausência de ISO, não tiveram quaisquer efeitos sobre a indução de letalidade por CEAI. A redução da mobilização de Ca2+ e o tratamento com BIS I não alteraram as curvas de letalidade, na presença ou ausência de ISO, mas provocaram significante aumento no tempo de recuperação das células após um choque não letal. As curvas em função de ?Vmax foram similares àquelas em função da intensidade do campo. Os resultados mostram que a estimulação ?-adrenérgica é capaz de proteger os miócitos dos efeitos deletérios do CEAI, permitindo que a célula suporte maiores ?Vmax. A proteção parece ser mediada por adrenoceptores ?1 e PKA, e possivelmente envolve ativação de mecanismos de reparo. Estas vias de proteção podem ser futuramente exploradas para atenuar os danos miocárdicos causados pela desfibrilação/cardioversão
Abstract: The myocardium is exposed to high-intensity electric fields (HIEF) during cardiac electric defibrillation, which may reverse life-threatening arrhythmias, but also cause cell damage. Impairment of cardiac pumping during ventricular fibrillation is usually associated with high sympathetic tone, and catecholamine infusion is a common procedure for the emergencial treatment of this arrhyhmia. The present study was carried out to investigate whether adrenergic stimulation affects the vulnerability of ventricular myocytes to the lethal effect of HIEF. Left ventricular myocytes were isolated from adult Wistar rat hearts by collagenase digestion. Under perfusion with Tyrode's solution at 23 ºC, cyclic contractile activity was evoked by stimulation at 0.5 Hz. A HIEF pulse was then applied, after which cells were allowed to rest and recover from the shock. Afterward, the protocol was repeated increasing HIEF amplitude until cell death ensued. The probability of cell death as a function of the field intensity or the estimated maximum change in membrane potential, ?Vmax (lethality curve) was determined by survival analysis. The protocol was carried out during exposure to 10 nM isoproternol (ISO), in the absence and presence of the ?1-adrenoceptor blocker metoprolol (MET, 150 nM), the PKA inhibitor H-89 (10 ?M), the PKC inhibitor BIS I (500 nM), or after a protocol designed to attenuate the increase in cell Ca2+ mobilization by ISO. Lethality curves were compared with the Mantel-Cox test. Exposure to ISO produced a marked rightward shift of the lethality curves (p< 0.01), and the field intensity associated with the cell death probability of 0.5 (EL50) was increased from 85 to 100 V/cm. Treatment with MET or H-89 alone did not significantly affect the curves, but completely abolished ISO protective effect. Decreasing Ca2+ mobilization and BIS I treatment did not produce significant effects on the lethality curves, either in the absence or presence of ISO, but they increased the time spent to cell recovery after a non-lethal shock. Similar results were obtained for the lethality curve as a function of ?Vmax. Therefore, ?-adrenergic stimulation confers protection to ventricular myocytes from the lethal effects of HIEF, even though cells apparently experience higher variations of ?Vmax, which should lead to extensive electroporation. This effect, which seems to be mediated by ?1-adrenoceptors and dependent on PKA activation, possibly involving recruitment of membrane repair mechanisms. This protective effect may be further explored as a means to attenuate HIEF deleterious effects on cardiac function that frequently result from electric defibrillation/cardioversion
Mestrado
Engenharia Biomedica
Mestre em Engenharia Elétrica
Michael, Kevin A. "An analysis of defibrillation and cardiac resynchronization therapy strategies in patients with failing systemic right ventricles." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/2827.
Full textThe expanding application of cardiac resynchronization (CRT) and implantable cardioverter-defibrillator therapy (lCD) to include patients with congenital heart disease requires careful evaluation of selection criteria and unconventional adaptive strategies to ensure clinical efficacy. A single centre prospective analysis of adults post atrial redirection surgery (Mustard operation) for dextro-transposition of the great arteries (d-TGA) presenting with systemic right ventricular (sRV) dysfunction and at risk of sudden cardiac death (SCD). All patients ( mean age 25 years, range 18-35) with varying functional disability{New York Heart Association (NYHA) II-III} receiving ICDs ± concomitant CRT were evaluated. Total follow-up period was 24 months. A patient individualized approach was used for device implantation. Endocardial, epicardial and transthoracic defibrillation strategies were examined in 5 consecutive cases. A hybridized form of CRT was employed in two patients. Only one patient demonstrated response to therapy while the other deteriorated during biventricular pacing (BVP). This prompted a novel approach to CRT using noncontact mapping (NCM) and acute intra-arterial blood pressure response to guide endocardialsRV lead placement in a single patient. The ejection fraction increased from 23 -33% within 1week post procedure and clinical improvement was sustained after 6-months follow-up. Application of CRT II CD therapy to patients with sRV dysfunction requires individualized and adaptive strategies to overcome anatomical constraints. This study represents a chronological and evolutionary account of these measures.
Wang, Yves Terence. "Effects of Interventions Following Myocardial Infarction: Defibrillation-Induced Electroporation and Reverse Remodeling Following Surgical Ventricular Reconstruction." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1327695637.
Full textWang, Yanqun. "Analysis of defibrillation efficacy and investigation of impedance cardiography with finite element models incorporating anisotropic myocardium /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8104.
Full textMoore, Michael John. "A study of the effectiveness of public access defibrillation in urban and rural populations in Northern Ireland." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479309.
Full textBrügmann, Tobias [Verfasser]. "Optogenetics in striated muscle: defibrillation of the heart and direct stimulation of skeletal muscles with light / Tobias Brügmann." Bonn : Universitäts- und Landesbibliothek Bonn, 2019. http://d-nb.info/1201727839/34.
Full textGRENIER, DE GAYARDON DE FENOYL FRANCE. "Defibrillation ventriculaire precoce : interet des defibrillateurs semi-automatiques ; a propos de 70 cas d'utilisation en milieu extra-hospitalier." Lyon 1, 1992. http://www.theses.fr/1992LYO1M092.
Full textGu, Yiping. "ENTRAINMENT OF ELECTRICAL ACTIVATION BY SPATIO-TEMPORAL DISTRIBUTED PACING DURING VENTRICULAR FIBRILLATION." UKnowledge, 2003. http://uknowledge.uky.edu/gradschool_theses/193.
Full textSekimoto, Miho. "The impact of basic emergency medical technician with defibrillation system on survival after out-of-hospital cardiac arrest in Japan." Kyoto University, 2003. http://hdl.handle.net/2433/148704.
Full textGolshayan, Maryam. "A study of internal defibrillation efficacy using finite element analysis: a 3D isotropic finite element model of the myocardium electric fields." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18790.
Full textLa fibrillation ventriculaire (FV) est un état dans lequel la cavité inférieure du coeur montre une motion asynchrone et chaotique, empêchant le coeur de pomper le sang et l'oxygène au corps. La FV est considérée comme un arrêt cardiaque soudain, responsable de la mort subite de 300,000 personnes chaque année aux Etats-Unis. Afin d'inverser cette condition mortelle, le recours le plus efficace est la délivrance d'un choc électrique directement au niveau du coeur à l'aide d'un Défibrillateur Cardioverteur Implantable (DCI). Le principal problème de l'utilisation des DCIs est le placement des électrodes défibrillateurs pour permettre au courant d'être conduit optimalment à travers du muscle cardiaque, en particulier, le myocarde ventriculaire gauche. Selon l'hypothèse de la masse critique, la défibrillation sera réussi quand 75% du tissu de myocarde est inactivé par le choc de défibrillation. Le seuil de défibrillation ou la tension efficace minimale exigée pour donner des résultats réussis est suggéré d'être liés à la distribution du gradient de la tension myocardique, toutefois, il n'a pas été mesurée. En outre, le but est de maintenir le seuil de défibrillation aussi bas que possible pour essayer de maximiser le succès de la défibrillation, réduire au minimum le risque des dommages de myocarde et des arythmies cardiaques provoqués par des chocs à haute intensité, et aussi permettre de réduire la taille de la batterie ainsi que prolonger la durée de la vie utile du dispositif. De diverses techniques numériques ont été utilisées pour modeler le coeur afin de résoudre les équations régissant requises pour obtenir la distribution de gradient de la tension myocardique pendant la défibrillation. La méthode des éléments finis (FEM) a été d'intérêt particulier car elle peut gérer les domaines irréguliers, les hétérogénéité de matériel, et les conditions aux limites complexe de problèmes dans la bioélec
Dahan, Benjamin. "Mort subite de l'adulte : stratégie de déploiement des défibrillateurs automatisés externes." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB092/document.
Full textOut-of-hospital cardiac arrest (OHCA) is a major public health concern. Early bystander cardiopulmonary resuscitation (CPR) and defibrillation are associated with higher survival rates for OHCA victims. Unfortunately, despite major efforts over the past decade, survival rates remain low in many communities. This work sought to highlight factors affecting public defibrillation, early CPR and public knowledge on defibrillation. We assessed different strategies for Automated External Defibrillators (AEDs) deployment. We also aimed to focus effect of neighborhood socio-economic status on bystander CPR. Finally, we sought to analyze public awareness of the AED nearest location and knowledge of AED use. All OHCAs attended by EMS in Paris between 2000 and 2010 were prospectively recorded and geocoded. We compared a guidelines-based strategy of placing an AED in locations where more than one OHCA had occurred within the past five years to two novel strategies: a grid-based strategy with a regular distance between AEDs and a landmark-based strategy. The expected number of AEDs necessary and their median (IQR) distance to the nearest OHCA were assessed for each strategy. We also evaluated the relationship between neighbourhood SES characteristics and the fact of receiving bystander CPR. Then, we performed a survey in three kinds of places (train station, city mall and public park) of all individuals within 100 meters from an AED to analyze their knowledge of the closest AED location and their confidence to use it. Of 4,176 OHCAs, 1,372 (33%) occurred in public settings. The guidelines-based strategy would result in the placement of 170 AEDs, with a distance to OHCA of 416 (180-614) meters and a continuous increase in the number of AEDS. In grid-based strategy, the number of AEDs and their distance to the closest OHCA would change with the grid size, with a number of AEDs between 200 and 400 seeming optimal. In landmark-based strategy, median distances between OHCAs and AEDs would be 324 meters if placed at post offices (n=195), 239 at subway stations (n=302), 137 at bike-sharing stations (n=957), and 142 at pharmacies (n=1466). Of the 4,009 OHCA with mappable addresses recorded, 777 (19.4%) received bystander CPR. Those receiving it were more likely to be in public locations, have had a witness to their OHCA, and to have collapsed in a non-low SES neighbourhood. In a multilevel analyses, bystander CPR provision was significantly less frequent in low than in higher SES neighbourhoods (OR 0.85; 95% confidence interval [CI] 0.72-0.99). A total of 301 people responded to the survey. About half respondents (49%) had a Basic Life Support training experience with 70 % of them trained after 2007 and 37% who attempted a one hour training initiation. The universal AED sign was recognized by 37% of all respondents and 64% could recognize an AED on a picture. The closest AED location was known by 16% of the respondents with a positive impact of training after 2007 and knowledge of AED sign and picture (p<0.0001). A majority of respondents (66%), considered they had the right to use an AED and 59% knew in which circumstances it is necessary to use it. Only 25% of the respondents declared to know how to use an AED. Our work presents an original evidence-based approach to strategies of AED deployment to optimize their number and location. This rational approach can estimate the optimal number of AEDs for any city. In Paris, OHCA victims were less likely to receive bystander CPR in low SES neighbourhoods. These first European data are consistent with observations in North America and Asia. Our survey conducted in places known to be at risk of OHCA highlights the need for a better AED visibility in public places and the need to improve public knowledge and confidence in the use of AED. (...)
Zoccoler, Marcelo 1987. "Estudo espaço-temporal da concentração de cálcio citosólico de miócitos cardíacos isolados expostos a campos elétricos de alta intensidade." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259736.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-25T18:17:39Z (GMT). No. of bitstreams: 1 Zoccoler_Marcelo_M.pdf: 48059333 bytes, checksum: f5fb08bbb5d770ad29791611d11fa8fa (MD5) Previous issue date: 2014
Resumo: A fibrilação ventricular é uma quadro extremamente grave de ameaça imediata à vida e a única terapia efetiva para sua reversão é a desfibrilação, que consiste na aplicação de campos elétricos (E) de alta intensidade sobre o coração. Este procedimento é capaz de restabelecer o sincronismo do coração, mas ele pode causar lesão em miócitos. A lesão depende da direção de E e é atribuída à eletroporação - formação de poros hidrofílicos na membrana celular - que leva a um aumento expressivo da concentração de íons Ca2+ livres no citosol ([Ca2+]i), resultante de influxo de Ca2+ extracelular pelos poros. Neste trabalho, produzimos um sistema de microfluorimetria capaz de registrar imagens de fluorescência de miócitos cardíacos isolados e estudamos a lesão causada por E de alta intensidade por meio do aumento da fluorescência associada a [Ca2+]i em miócitos orientados longitudinalmente e transversalmente a E. As células foram carregadas com o indicador de fluorescência Fluo-3, estimuladas a 0,5Hz por E de baixa intensidade antes da aplicação de um pulso de E de alta intensidade sub-letal. As imagens de fluorescência foram capturadas por uma câmera EMCCD e processadas por um software específico desenvolvido neste trabalho. O software utilizou dois métodos de análise: média de fluorescência normalizada e razão de uma área que mostrou aumento significativo de fluorescência dividida pela área total da célula. Análise de regiões de interesse (ROIs) voltadas para o ânodo e o cátodo produziu resultados em concordância com a literatura, com maior lesão (inferida por aumento de [Ca2+]i) no lado do ânodo (P<0,05 nos dois os métodos). A comparação entre os grupos longitudinal e transversal apresentou diferença estatística relevante no método da razão de áreas, o que não ocorreu pelo método de média de fluorescência. Imaginamos que a utilização de uma técnica mais direta para medir eletroporação possa solidificar esta correlação entre orientação e lesão. A compreensão dos mecanismos responsáveis pela severidade das lesões é importante para desenvolver terapias mais seguras
Abstract: Ventricular fibrillation is an extremely dangerous immediate life-threatening condition and the only effective therapy to its reversion is defibrillation, which consists in applying high intensity electric fields (E) on the heart. Such procedure is capable of reestablishing heart synchronism, but it may also cause lesion in myocytes. Lesion is associated to E direction and is assigned to electroporation - generation of hydrophilic pores across the membrane caused by high intensity E - which results in an expressive increase in cytosol free Ca2+ concentration ([Ca2+]i), a consequence from extracellular Ca2+ influx through the pores. In this work, we produced a microfluorimetry system capable of recording isolated cardiomyocytes fluorescence images and studied lesion caused by high intensity E by the means of the rise in [Ca2+]i associated fluorescence in myocytes oriented longitudinally and transversally to E. Cells were loaded with fluorescent dye Fluo-3, paced at 0,5Hz with low intensity E before setting one sub-lethal high intensity E pulse. Fluorescence images were recorded by an EMCCD camera and processed by a specific software developed in this work. The software used two analysis methods: normalized fluorescence average and a ratio of an area showing most significant fluorescence increase divided by cell total area. Regions of interest (ROIs) analysis facing the anode and the cathode has produced results in accordance with literature, presenting higher lesion (inferred by [Ca2+]i increase) at anode side (P<0,05 in both methods). Comparison between longitudinal and transversal groups has presented relevant statistic difference when the ratio of areas method was employed, which has no happened when employing the fluorescence average method. We imagine that using a straight-foward technique for assessing electroporation may solidify this correlation between orientation and lesion. The understanding of the mechanisms responsible for lesion severity is important to develop safer therapies
Mestrado
Engenharia Biomedica
Mestre em Engenharia Elétrica
Varma, Pryamvada Yasomatee. "Effect of combination I¦K¦1 and I¦K¦r blockade on defibrillation and cardiac refractoriness in the isolated Langendorff rabbit heart model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0021/MQ54171.pdf.
Full textGercken, Martina [Verfasser], Daniel Peter [Verfasser] Franzen, and Wilhelm [Verfasser] Krone. "Klinische Studie zur elektrischen Therapie von Vorhofflimmern mittels R-Zacken gesteuerter Cardioversion versus Defibrillation (VCD-Studie) / Martina Gercken, Daniel Peter Franzen, Wilhelm Krone." Köln : Deutsche Zentralbibliothek für Medizin, 2019. http://d-nb.info/1196880506/34.
Full textStrutz, Joanna [Verfasser], Dietrich [Akademischer Betreuer] Kettler, Jean-François [Akademischer Betreuer] Chenot, and Christina [Akademischer Betreuer] Unterberg-Buchwald. "Strukturelle Erwägungen zur Implementierung der automatisierten externen Defibrillation im Landkreis Göttingen / Joanna Strutz. Gutachter: Jean-François Chenot ; Christina Unterberg-Buchwald. Betreuer: Dietrich Kettler." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://d-nb.info/1042530432/34.
Full textGercken, Martina [Verfasser], Daniel Peter Verfasser] Franzen, and Wilhelm [Verfasser] [Krone. "Klinische Studie zur elektrischen Therapie von Vorhofflimmern mittels R-Zacken gesteuerter Cardioversion versus Defibrillation (VCD-Studie) / Martina Gercken, Daniel Peter Franzen, Wilhelm Krone." Köln : Deutsche Zentralbibliothek für Medizin, 2019. http://d-nb.info/1196880506/34.
Full textAbu, Nahleh Kais [Verfasser], Torsten [Akademischer Betreuer] Birkholz, Torsten [Gutachter] Birkholz, and Jürgen [Gutachter] Schüttler. "Untersuchung des Nutzens und der unmittelbaren Auswirkung von Schrittmacherimpulsen nach Defibrillation bei Kammerflimmern / Kais Abu Nahleh ; Gutachter: Torsten Birkholz, Jürgen Schüttler ; Betreuer: Torsten Birkholz." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019. http://d-nb.info/1185171231/34.
Full textFinzi, A. A. "AMPLITUDE SPECTRUM AREA AS A PREDICTOR OF SUCCESSFUL DEFIBRILLATION: THRESHOLD VALUES ANALYSIS IN A LARGE DATABASE OF OUT-OF-HOSPITAL CARDIAC ARREST TREATED BY DC-SHOCK." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/217617.
Full textTiming of defibrillation (DF) to interrupt ventricular fibrillation (VF) is of utmost importance as it implies interruption of chest compression and,in case of failure, the risk of adding further damage to the already critical myocardial condition. In such scenario, a real-time indicator of the probability of success is needed . This study was aimed to the capability of “Amplitude Spectrum Area” (AMSA) to predict DF outcome in a large database of out-of-hospital cardiac arrest. Electrocardiographic (ECG) data recorded by automated external defibrillators were obtained from 8.419 cardiac arrest events occurring in 7 provinces in Lombardia Region, Italy, between 2008 and 2009. Among these events, only VF/VT cardiac arrests receiving DFs were selected (n=1055). A 2 sec ECG window ending at 0.5 sec before DF was analyzed and AMSA calculated, after fast Fourier transformation. DF was defined as successful in the presence of spontaneous rhythm 40 bpm starting within 60 secs from the DF. Threshold values of AMSA able to discriminate DF outcome were individuated and sensitivity, specificity, accuracy, positive and negative predictive values (PPV, NPV) were calculated. The area under the receiver operating characteristic (ROC) curve was measured. A total of 2.442 quality DF events, including 1055 first attempts and 1.387 subsequent ones were included in the analyses. DF success rate was of 26%, 27%, and 25.2% for all, first, and subsequent DFs, respectively. AMSA was significantly greater prior to successful DFs, compared to that preceding unsuccessful ones (13.8 vs. 6.9 mV-Hz, and 13.9 vs. 6.8 mV-Hz, and 13.7 vs. 7 mV-Hz, for all, first, and subsequent DFs respectively). Intersection of sensitivity, specificity and accuracy curves identified a threshold value of AMSA of approximately 9.5 mV-Hz, able to predict DF outcome, with a balanced sensitivity, specificity and accuracy of 80%, for all, first, and subsequent DFs . Moreover, intersection of PPV and accuracy curves identified a threshold value of AMSA of approximately 15 mV-Hz able to predict a successful DF with a PPV and accuracy of 80%, for all, first, and subsequent DF attempts. AMSA values greater than 27 mV-Hz correctly predicted the success of DF with a PPV value of 100%. AMSA below 8 mV-Hz correctly predicted the DF failure with a NPV of > 95%, for all, first, and subsequent DFs. Further decreases in AMSA values below 4 mV-Hz achieved a NPV of 100%. Area under ROC curves was 0.872, 0.869, and 0.875 for all, first, and subsequent DFs, respectively In this large patient population, an AMSA algorithm was capable to predict DF outcome with high accuracy. A specific AMSA threshold in order to predict DF outcome, i.e. success or failure, may be identified during CPR. An AMSA-based DF decision therefore would be an useful approach to guide the best CPR intervention.
Hebert, Robin Lewis. "Initiation of In-hospital CPR: An Examination of Nursing Behaviour Within their Scope of Practice." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35804.
Full textBLEUEZ, NATHALIE. "La defibrillation ventriculaire precoce en milieu extra-hospitalier : interet des defibrillateurs semi-automatiques ; a propos de 140 cas ; etude menee pour le samu regional de lyon." Lille 2, 1993. http://www.theses.fr/1993LIL2M199.
Full textFonseca, Alexandra Valenzuela Santelices da. "Estimulação multidirecional de celulas cardiacas : instrumentação e experimentação." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259396.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-15T01:38:31Z (GMT). No. of bitstreams: 1 Fonseca_AlexandraValenzuelaSantelicesda_M.pdf: 1311974 bytes, checksum: ab061a6f8d63a1175d6a3c9281e0704e (MD5) Previous issue date: 2009
Resumo: O procedimento mais efetivo para reverter arritmias cardíacas consiste na aplicação de choques elétricos de alta intensidade, como e o caso da desfibrilação. Estimulação com campos elétricos (E) elevados, entretanto, exerce efeitos deletérios sobre o músculo cardíaco, podendo causar disfunções elétrica e contrátil e até a morte celular. Privilegiar a estimulação na direção longitudinal, para qual o limiar de excitação das células cardíacas e menor, seria uma forma de se reduzir a amplitude do estimulo sem perder a efetividade da estimulação. Para isto, foi desenvolvido e testado, em miócitos ventriculares orientados de maneira aleatória, um sistema de estimulação multidirecional automática que permite o chaveamento controlado de estímulos sequênciais para três diferentes pares de eletrodos (cada um correspondendo a uma direção) em um intervalo de tempo inferior a duração do potencial de ação (período em que a célula se encontra eletricamente refrataria). A estimulação multidirecional com uma intensidade de E 20% acima do limiar estimulatório (1,2× ETM) dobrou o recrutamento (excitação) de células (80 vs. 40% com estimulação unidirecional, p<0,001). Adicionalmente, o recrutamento com a estimulação multidirecional automática foi maior (p< 0,001) do que a soma dos recrutamentos obtidos com a estimulação em cada direção individualmente (sem intersecção), o que sugere que a estimulação sublimiar durante o procedimento automático pode aumentar a excitabilidade celular. Foi observado também que, para uma dada amplitude do estimulo, o uso da forma de onda bipolar (para a qual o valor de ETM foi menor que para pulsos monopolares: 3,2 ± 0,1 vs. 3,9 ± 0,1 V/cm; p< 0,001) promoveu um recrutamento maior do que com o pulso monopolar (recrutamento de 50% das células foi obtido com 2,97 ± 0,04 e 4,18 ± 0,05 V/cm para pulsos bipolares e monopolares, respectivamente; p< 0,05). A combinação da estimulação multidirecional automática com o uso da forma de onda bipolar permitiu, portanto, uma redução de cerca de 50% no valor do E absoluto (3,8 vs. 7,8 V/cm com estimulação unidirecional e pulso monopolar) para um recrutamento de ~80% das células. A aplicação destes procedimentos na estimulação cardíaca (marcapasso e desfibrilação) pode otimizar o processo, levando a uma melhor eficiência e uma menor incidência de lesão.
Abstract: The most effective procedure to revert cardiac arrhythmias consists in the application of high intensity electric discharge, such as in cardiac defibrillation. Nevertheless, stimulation using high electric fields (E) may cause injury to the cardiac muscle, generating electric and contractile dysfunctions and even cell death. A possible way to reduce the stimulus intensity while maintaining the stimulation effectiveness would be stimulate cardiac cells with E applied parallel to the cell major axis, in which case the stimulation threshold is lower. To test this possibility, a multidirectional stimulation system was developed and tested on randomly-oriented rat ventricular myocytes. The system allows the controlled switching of sequential stimuli delivered to three different pairs of electrodes (each one corresponding to one direction), in a period shorter than the action potential duration (when cell is electrically refractory). The multidirectional stimulation with E intensity 20% above the stimulation threshold (1.2× ETM) doubled the percentage of recruited (excited) cells (~80 vs. ~40 % with unidirectional stimulation, p<0.001). Additionally, recruitment with automatic multidirectional stimulation was greater (p< 0.001) than the sum of recruitments obtained from stimulation of each direction individually (without intersection), which is suggestive that subthreshold stimulation during the automatic procedure might enhance cell excitability. Moreover, it was observed that for a given absolute stimulus amplitude, the use of biphasic waveforms (for which ETM was lower than for monophasic pulses: 3.2 ± 0.1 vs. 3.9 ± 0.1 V/cm; p< 0.001) promoted higher recruitment than monophasic stimuli (50% recruitment was attained with 2.97 ± 0.04 and 4.18 ± 0.05 V/cm with biphasic and monophasic pulses, respectively; p< 0.05). Thus, the association of automatic multidirectional stimulation and biphasic waveform enabled a 50% reduction of the absolute E value (3.8 vs. 7.8 V/cm with unidirectional stimulation and monopolar pulse) to evoke excitation in ~80% of the cells. The application of these procedures to cardiac stimulation (pacemaker and defibrillation) might optimize the process, leading to greater efficiency and lower injury incidence.
Mestrado
Engenharia Biomedica
Mestre em Engenharia Elétrica
Marijon, Eloi. "Mort subite au cours d’une activité sportive : étude en population générale." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05S009.
Full textBackground – Although such data are available for young competitive athletes, the prevalence, characteristics and outcome of sports-related sudden cardiac death have not previously been assessed in the general population.Methods – A prospective and comprehensive national survey was carried out throughout France by the French Institute of Health and Medical Research from 2005 to 2010, involving subjects aged 10–75 years. Case detection for sports-related sudden cardiac death, during competitive or leisure activities, including resuscitated cardiac arrest, was undertaken via emergency medical services (Service d’Aide Médicale Urgente, SAMU) reporting and web-based screening of media releases. Data were collected according to Utstein’s style. Incidence calculations were reported by million of inhabitants as well as million of sports participants. Specific analyses were also carried out among women and specific sports. After having documented major regional survival disparities, we identified to which extent conventional evidence-based individual factors, known to be associated to survival, were distributed among different groups of survival. Moreover, we assessed if functional outcome was variable among groups of survival. Factors associated with survival were analyzed using regression logistic model.Results – The overall burden of sports-related sudden cardiac death was estimated between 5 and 17 cases per million inhabitants per year. Only 6% of cases occurred among young competitive athletes, with a specific incidence calculated to 9.8 (95% CI 3.7–16.0) per million per year. After considering participation rates, incidence in men sport participants was estimated from 11.2 (95% CI 10.4–12.1) to 33.8 (95% CI 30.9–36.8) per million of participants per year, dramatically higher than women-related incidence, particularly in the 45–54 year range (relative risk 0.03, 95% CI 0.01 to 0.07). By contrast with women, the incidence of sports-related sudden cardiac death in men significantly increased over age categories (p<0.0001), and incidence rates were substantially higher in men aged >35 years than men aged 35 years or less (RR 2.51, 95% CI 2.10–3.01). The mean survival rate at hospital discharge was 15.7% (95% CI 13.2–18.2), with major regional disparities among districts (from 0 to 47%), with however a highly similar favorable neurological outcome (80%). No difference was observed regarding subjects’ characteristics and circumstances of occurrence (including presence of witnesses, delays of intervention and public use of automatic external defibrillators) across survival groups. By contrast, major differences were noted regarding bystander initiation of cardiopulmonary resuscitation (15% to 81%, p<0.001) and presence of initial shockable rhythm (29% to 79%, p<0.001). Public use of automatic external defibrillator was dramatically low (<1%). Independent factors for survival included bystander cardiopulmonary resuscitation (OR 3.73, 95% CI 2.19–6.39, p<0.0001), initial shockable rhythm (OR 3.71, 95% CI 2.07–6.64, p<0.0001) and short delay between cardiac arrest and resuscitation (OR 1.32, 95% CI 1.08–1.61, p=0.006). After adjustment on individual factors, only population education to Basic Life Support was significantly associated with survival (OR 1.64, 95% CI 1.17–2.31, p=0.004).Conclusions and perspectives – Sudden cardiac death is a public health issue, with the need for a multidisciplinary approach involving Emergency Cares, Cardiology, and Epidemiology. Regarding sports-related sudden death, our conclusions are the following (...)