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Claudon, Laurent. "Contribution au développement de modules d'acquisition et de traitements de l'électrocardiogramme endocavitaire dans un stimulateur cardiaque implantable." Nancy 1, 1993. http://www.theses.fr/1993NAN10043.
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L'acquisition et la détection de l'activité cardiaque endocavitaire font l'objet de ce mémoire. Cet ensemble, qui est intégré dans un stimulateur cardiaque implantable, constitue une partie essentielle d'un tel appareil car, l'entrainement du cœur par stimulations électriques est conditionné par l'absence de détection d'événements cardiaques endocavitaires appelés ondes p et r. Ce mémoire comprend successivement une présentation de l'activité électrique du cœur et du stimulateur cardiaque, un développement de l'ensemble d'acquisition comprenant un filtrage passif, une amplification à base de capacités commutées et une numérisation par convertisseur à modulation delta, une partie détection des ondes p et r avec plusieurs modules de traitements lies aux problèmes de récupération du signal après stimulations et aux perturbations engendrées par le phénomène de diaphonie et enfin, quelques réflexions sur la compression de données et la reconnaissance de formes des complexes cardiaques en vue d'une intégration dans une future génération de stimulateurs
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Strandberg, Lovisa, and Petronella Karlsson. "Att leva med pacemaker." Thesis, Malmö högskola, Fakulteten för hälsa och samhälle (HS), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-25507.
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Bakgrund: Att drabbas av en hjärtsjukdom är skrämmande och medför vissa begränsningar för individen. I fall tillståndet kan förbättras av att få en pacemaker implanterad, påverkar detta patienten och des anhöriga på flera olika plan. De främsta anledningarna till att få denna åtgärd är en för långsam puls eller förmaksflimmer. De elektriska impulserna som ska skapa hjärtkontraktionen sprider sig då inte genom hjärtat som den ska. Med hjälp av elektroder som förts ned till hjärtat, tar pacemakern över hjärtats impulsstyrning genom att utlösa en depolarisation vid tillstånd där den normala aktiviteten har upphört eller blivit så inefektiv att det är risk för en cirkulatorisk svikt. En pacemaker botar inte den bakomliggande orsaken till den låga pulsen utan tar enbart bort eller lindrar de fysiologiska symtomen. För en patient är detta en möjlighet till att återfå kraft och fortsätta leva. Syfte: Syftet med denna studie var att belysa personers upplevelse av att leva med pacemaker. Metod: Den valda metoden är en litteraturstudie genom databassökning efter vetenskapliga artiklar, för att kunna se över den kunskap som finns inom ämnet. Resultatet baseras på en granskande resultatanalys av elva vetenskapliga artiklar, funna via sökning i databaserna CINAHL, Pubmed, Google Scholar och Socialogical abstracts. Resultat: Resultatet delades upp i fem huvudteman som representerade fynden i de artiklar som valts att ha med i studien. Dessa var: upplevelse av begränsningar på grund av känslighet för elektromagnetiska fält; upplevelse av förändrad energi och möjlighet till aktivitet; upplevelse av inverkan på det sociala samspelet; upplevelse av en ändrad relation till livet och döden; upplevelse av att förhållandet till kroppen påverkats av pacemakerimplantatet. Slutsats: Att leva med en pacemaker har visat sig vara en stor omställning för många, men det finns även de som inte ser det som något stort. Allas upplevelser är unika men det finns somliga som är återkommande och dessa kan vara bra för vårdpersonal att känna till för att kunna möta patienten i dennes verklighet.Background: To suffer from a heart disease is frightening and imposes certain restrictions on the individual. In case the condition can be improved by getting a pacemaker implanted, this affects the patient and their relatives on several different levels. The premier reason to have a pacemaker implanted is because of a slow pulse or atrial fibrillation. The electrical impulses that should generate the contraction of the heart do not distribute the impulses. With electrodes connected with wires to the heart, the pacemaker takes over the impulse control of the heart by triggering a depolarization when the normal activity has stopped or is to inenfective for the circulation to be unaffected, which can lead to a circulation failure. The pacemaker does not cure the cause of the slow pulse, but can reset it or moderate the physiological symptoms. For a patient, this is an opportunity to regain power and continue living. Objective: The objective with this study was to illustrate individuals experience living with a pacemaker. Method: The chosen method was a litterature review by searching databases to find scientific articles, to be able to review the knowledge within the matter. The result was based on a review of the results of eleven scientific articles, found by searching the databases CINAHL, Pubmed, Google Scholar and Socialogical abstracts. Results: The results was divided into five themes which represented the findings in the articles chosen for this study, which were: experiencing limitations due to sensitivity to electromagnetic fields; experiencing changes in energy and opportunity to activity; experiencing an impact on social interaction; experiencing a different view to life and death; experiencing the relation to the body has been affected by the pacemaker implant. Conclusion: Living with a pacemaker has been shown to be a major adjustment for many, but there are also those who do not see it as something big. Everyone's experience is unique, but there are some that are recurring and may be useful for health professionals to be aware of in order to meet the patient in his or her reality.
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Brattoli, Luca. "Elettrofisiologia del cuore e pacemaker." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14176/.
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La tesi tratta del normale funzionamento del cuore in un paziente sano, il ciclo cardiaco con le relative fasi e l'elettrocardiogramma. E alcune delle possibili cause di un paziente malato che richiede l'uso del pacemaker. Analisi di come è strutturato un laboratorio di elettrofisiologia, la preparazione del paziente pre e post-operatorio e gli strumenti necessari. Analisi della storia del pacemaker partendo dai suoi componenti principali. I vari tipi di pacemaker e le modalità di stimolazione. Analisi più approfondita di un pacemaker guidato da un sensore, le indicazioni per l'impianto di pacemaker permanenti e le relative tecniche di inserimento.
Per concludere i problemi dovuti e i possibili malfunzionamenti dei pacemaker permanenti e il pacemaker più piccolo del mondo.
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Bub, Gil. "Optical mapping of pacemaker interactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0033/NQ64526.pdf.
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Gribbin, Guy M. "Pacemaker mode and patient outcome." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409718.
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Prosser, Nicola Louise. "A dual-sensor diagnostic recording pacemaker." Thesis, University of Exeter, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262434.
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Sulke, Alfred Neil. "Modern pacemaker modes and everyday activity." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316433.
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Novelli, Elisa. "Dispositivi cardiaci impiantabili: pacemaker e defibrillatori." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5158/.
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Jansson, Caroline, and Martina Bodin. "Att leva med pacemaker : En litteraturöversikt." Thesis, Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för omvårdnad, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-34702.
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Bakgrund: I Sverige är det cirka 53 000 personer som lever med pacemaker. Att vara beroende av pacemaker kan ha stor inverkan på personens liv. Sjuksköterskan har som roll att ge personcentrerad omvårdnad genom att se till varje individs egna upplevelser av hälsa och ohälsa. Hälsorelaterad livskvalitet (HRQoL) är ett omfattande begrepp som beskriver upplevt välbefinnande fysiskt, psykiskt och socialt. Syfte: Var att beskriva om och på vilket sätt det dagliga livet påverkas av att leva med pacemaker. Metod: En litteraturöversikt med kvantitativa och kvalitativa artiklar har sammanställts utifrån deduktiv ansats. Begreppet HRQoL har använts som teoretisk referensram. Det har gjorts artikelsökningar i databaserna CINAHL, MEDLINE och PsycINFO. Det resulterade i åtta artiklar som analyserades utifrån Elo och Kyngäs innehållsanalys. Resultat: HRQoL förbättrades efter att personer fått pacemaker inopererad. Personer mötte fysiska, psykiska och sociala utmaningar, men pacemakern upplevdes som något positivt då de fått en livsräddande behandling. Slutsats: Att leva med pacemaker är en komplex och individuell upplevelse som kan påverka det dagliga livet. Sjuksköterskan har en viktig roll genom att informera, undervisa, stötta och bemöta dessa personers upplevelser.
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Toff, William Daniel. "Cardiac pacemaker function in the aviation environment." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309309.
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Gierula, John. "Optimisation of pacemaker therapy for cardiac function." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17864/.
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Patients with right ventricular (RV) pacemakers are at increased risk of left ventricular (LV) systolic dysfunction (LVSD) and chronic heart failure (CHF). I aimed 1) to establish the prevalence of LVSD in patients with long-term RV pacemakers listed for pulse generator replacement (PGR), 2) to evaluate the effects on LV function of reprogramming existing pacemakers to reduce RV pacing (RVP) and 3) to investigate whether upgrade to cardiac resynchronization therapy (CRT) at the time of PGR is beneficial in patients with unavoidable RV pacing and LVSD. Data were collected on 491 patients listed for PGR. Reduced left ventricular ejection fraction (LVEF) < 50% was observed in 40%. Multivariable analysis revealed %RVP, serum creatinine and previous myocardial infarction (MI) to be independently related to the presence of LVSD. An audit was performed to investigate the effects of optimising pacemaker programming to avoid RV pacing in 66 patients. At 6m, RV pacing was reduced by a mean of 49%, with a mean improvement in LVEF of 6% and no reduction in exercise capacity, NT-pro-BNP or quality of life. Fifty patients with unavoidable RV pacing, LVSD, and mild symptoms of CHF, listed for PGR were randomized 1:1 to either standard RV-PGR or CRT. At 6 months there was a difference in change in median LVEF, improvements in exercise capacity, quality of life, and NT-proBNP in those randomized to CRT. After 809 days, 17 patients had died or been hospitalized (6 CRT and 11 PGR) and two patients in the PGR arm required CRT for deteriorating CHF. In summary, LVSD is common in patients with standard RV pacemakers and relates to cardiovascular co-morbidities, careful reprogramming to avoid unnecessary RV pacing can improve LVEF without adversely affecting exercise capacity and quality of life and upgrading patients with unavoidable RV pacing to CRT at PGR improves LV function, and exercise tolerance and may reduce admissions and further upgrades.
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Kurcheti, Krishna Kiran. "Understanding and implementing different modes of pacemaker." Kansas State University, 2012. http://hdl.handle.net/2097/14101.
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Master of ScienceDepartment of Computing and Information Sciences
John Hatcliff
The Heart is a specialized muscle that contracts regularly and continuously, pumping blood to the body and the lungs. Heart’s natural Pacemaker, the SA node is responsible for this pumping action by causing a flow of electricity through the heart. These electrical impulses cause the atria and ventricles to contract and thereby pump the blood to different parts of the body. Malfunction of the SA node leads to a disturbance in the heart’s rhythm in which heart beats lower than 60 times a minute ending up with Bradycardia. It also leads to ventricular arrhythmia which disrupts the ability of the ventricles to pump blood effectively to the body. This can cause a loss of all blood pressure leading to cardiac arrest and eventually death. In order to restore the heart’s natural healthy rhythm, an artificial pacemaker is necessary. A Pacemaker adapts to the present condition of the heart and responds to the heart by either pacing or just sensing it. It paces whenever there is some problem in the heart’s electrical activity and inhibits the pace when there is a proper intrinsic beat. There are various modes in which Pacemaker can operate based on the condition of the heart. Ventricles and atria are individually paced in few modes such as VOO, VVT, VVI, AOO, AAT, and AAI and paced together in some modes such as DVI, DI, DDD, DDDR as per the requirement of the heart. The main goal of this report is to understand the various modes, their nomenclature, working strategy, developing the pseudo code and implementing different modes namely VOO, AOO, VVI, AAI, VVT and AAT modes using an academic, dual chamber pacemaker.
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Mengistu, Jomo. "Study of The Electrical Properties of Pacemaker Leads." Thesis, University of Gävle, Ämnesavdelningen för elektronik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4403.
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Abstract
The purpose of this thesis is to examine the electrical properties of pacemaker leads by measurements and theoretical analysis.
If time allows, recommendations on how to construct a simple circuit model to explain the phenomenon will be given based on the electrical properties obtained from measurements performed during the work of this thesis. Additional information on pacemaker lead heating during impact of magnet in X-ray (MRI) will be presented if time allows. Significant electrical properties of pacemaker leads are compiled in this thesis.
ANALYSIS OF CIRCUIT MODEL
The purpose of this model is to create an equivalent electronic circuit model that describes a pacemaker lead electrical property. The model is divided into three different sections: proximal part, the homogeneous coil part and the distal end. The model will include series inductance, parallel capacitance, series resistance, lossless admittance and winding capacitance between each loop for the homogeneous coil part, additionally the impedance of the proximal and distal part will be included.
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Murphy, Philip Patrick. "Characteristics and clinical application of modern pacemaker therapy." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335952.
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Hettwer, Peter Jacob. "Individualized Cardiac Resynchronization Therapy: Next Generation Pacemaker Controls." Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27887.
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Cardiac dyssynchrony (CD) causes some heart muscle regions to contract at different times, and current treatments do not help 30 ? 50% of patients. In this thesis, multi-site pacing control schemes are created to quantitatively and automatically reduce the CD of ventricular wall accelerations by adjusting pacing times. Two and four left ventricular region models are investigated containing model variables that represent numerous muscle parameters. Optimization is performed using exhaustive search and genetic algorithm techniques, with particular attention paid to the latter with regard to development, parameter selection, and limitations. Relative to treatments firing all regions simultaneously, timing adjustment improves acceleration CD by up to 56%. Furthermore, simulations also demonstrate improvements to dyssynchronous region power generation and workload by up to 50% and up to 15% decrease in healthy region workload. Thus, the current model indicates it may be possible to improve acceleration CD by adjustments to regional firing times.
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Gillström, Richard, Anna Wibergh, and Fredrik Fransson. "En bekrivning av livskvalitet hos personer med pacemaker." Thesis, Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för omvårdnad, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-35688.
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Sammanfattning Bakgrund: I Sverige har cirka 55000 personer pacemaker. Att denna teknik förlänger deras liv är sedan länge känt. För sjuksköterskan är det av intresse att ta del av hur en pacemaker påverkar livskvaliteten för att kunna skapa verktyg för att bemöta denna patientgrupp. Denna litteraturöversikt har genomförts på artiklar som mätt livskvalitet hos patienter med pacemaker med hjälp av två olika mätinstrument. Syfte: Att, med hjälp av SF-36 och Aquarel, beskriva livskvaliteten hos personer med pacemaker. Metod: En litteraturöversikt med 13 kvantitativa artiklar har genomförts, med livskvalitet i fokus. Artiklarna var skrivna mellan 2001-2016 och söktes fram via databaserna CINAHL och Medline. Resultat: En pacemaker påverkar livskvaliteten positivt, de största signifikanta ökningarna visade sig i SF-36 mätområden fysisk rollfunktion och vitalitet. Men även i Aquarels mätområden arytmier och dyspné/ansträngning. Slutsats: Att få en pacemaker implanterad upplevs påverka patientens livskvalitet positivt. Men det ett komplext område som kräver personcentrerad vård. Där har sjuksköterskan en stor del i vård och omvårdnad. En väl utbildad och påläst vårdpersonal kan göra stor skillnad för patienten.
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Blüme, Sofia, and Louise Liviken. "Att leva med pacemaker - patienters upplevelser och livskvalitet." Thesis, Karlstads universitet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-65374.
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Torrente, Angelo. "Rôle de la signalisation calcique dans la génération et régulation de l’activité pacemaker du cœur." Thesis, Montpellier 1, 2011. http://www.theses.fr/2011MON1T023/document.
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Les pathologies du nœud sino-atrial provoquent un dysfonctionnement intrinsèque de l'automaticité de ce tissu. La maladie, l'âge ou une anomalie génétique peuvent être la cause d'un dérèglement de la fréquence cardiaque associé à la bradycardie ou la dysfonction atrio-ventriculire. Sans intervention médicale cette pathologie peut conduire à l'arrêt cardiaque. Les pathologies touchant le sinus sont fréquentes, avec une occurrence accrue dans la population âgée. Ainsi, avec le vieillissement des populations occidentales il devient primordial de mieux comprendre les mécanismes générant l'activité automatique du cœur. Les nombreuses études déjà réalisées dans ce domaine ont conduit à une forte controverse entre deux modèles explicatifs des mécanismes pacemaker. Dans ce contexte, j'ai étudié au cours de cette thèse le rôle joué par les canaux calciques Cav1.3 dans la génération de l'activité pacemaker. Afin de distinguer et expliquer le rôle des différents canaux ioniques impliqués dans le mécanisme pacemaker nous avons utilisé une combinaison d'outils pharmacologiques et plusieurs souches de souris transgéniques dont les gènes impliqués dans l'activité pacemaker étaient inactivés ou leur fonction modifiée. Dans le but de constituer un nouveau cadre d'interprétation du mécanisme pacemaker, plusieurs approches expérimentales ont été utilisées. L'activité pacemaker a été étudié dans 3 systèmes au niveau de complexité croissant: des cellules sino-atriales isolées, des tissus sino-atriales entiers et des animaux vivants. Ces différentes approches ont permis d'obtenir des résultats probants et ouvrent la voie à une meilleure compréhension de l'automaticité. En conclusion de cette thèse, nous proposons un cadre intégratif des modèles préexistants, dans lequel les canaux de la membrane cytoplasmique et les libérations de calcium interagissent pour générer un mécanisme pacemaker complexeThe “sick sinus syndrome” has been defined as an intrinsic dysfunction of the heart Sino-atrial node to perform its pacemaking function. Disease, ageing, or gene defects may cause sinus dysfunctions, ranging from rhythm disturbance to bradycardia, sinus pauses, sinus arrest, and arrhythmias. Without medical intervention these dysfunctions can result in heart block. Sick sinus syndrome is a common pathology, with an increased penetration in the elder population. In the light of the actual increase of elderly in western population, a better comprehension of the mechanism generating spontaneous automaticity appears fundamental. Several investigations have been already carried out in the field of automaticity, leading to a heated controversy between two models of the pacemaker mechanism. In the light this controversy, we investigated the role of Ca2+ channels in generating pacemaker activity. In order to discern and explain the roles of different ion channel actors already implicated in the complex pacemaker machinery we used a combination of pharmacological tools and a variety of transgenic mice. These mice present genetic inactivation or modification in genes involved in pacemaker activity. Furthermore, to provide a new framework for interpreting the pacemaker mechanism, different experimental approaches have been employed. Pacemaker activity was studied in three systems with increasing complexity: isolated sino-atrial cells, intact sino-atrial tissues and in freely-moving animals. These systems led us to consistent conclusions and will pave the way to a better understanding of pacemaking. In particular, we propose an integrative framework for bridging current models in a common mechanism where both, membrane channels and Ca2+ release interact generating a complex pacemaker machinery
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Danilović, Dejan. "Advances in cardiac pacing : clinical aspects of novel pacemaker leads and algorithms. Behavior of stimulation thresholds and impedances in modern pacemaker systems." [S.l.] : Medical department A university of Bergen, 1998. http://catalogue.bnf.fr/ark:/12148/cb37571604x.
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Cloherty, Shaun Liam Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Cellular interaction in the cardiac pacemaker: a modelling study." Awarded by:University of New South Wales. Graduate School of Biomedical Engineering, 2005. http://handle.unsw.edu.au/1959.4/22512.
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In mammalian hearts, initiation of the heartbeat occurs in a region of specialised pacemaker cells known as the sinoatrial node (SAN). The SAN is a highly complex spatially distributed structure which displays considerable cellular heterogeneity and is subject to complex electrotonic interactions with the surrounding atrial tissue. In this study, biophysically detailed ionic models of central and peripheral SAN pacemaker cells are described. These models are able to accurately reproduce experimental recordings of the membrane potential from central and peripheral SAN tissue. These models are used to investigate frequency synchronisation of electrically coupled cardiac pacemaker cells. Based on simulation results presented, it is proposed that cellular heterogeneity in the SAN plays an important role in achieving rhythm coordination and possibly contributes to the efficient activation of the surrounding atrial myocardium. This represents an important, previously unexplored, mechanism underlying pacemaker synchronisation and cardiac activation in vivo. A spatial-gradient model of action potential heterogeneity within the SAN is then formulated using a large-scale least squares optimisation technique. This model accurately reproduces the smooth spatial variation in action potential characteristics observed in the SAN. One and two dimensional models of the intact SAN are then formulated and three proposed models of SAN heterogeneity are investigated: 1) the discrete-region model, in which the SAN consists of a compact central region surrounded by a region of transitional pacemaker cells, 2) the gradient model, in which cells of the SAN exhibit a smooth variation in properties from the centre to the periphery of the SAN, and 3) the mosaic model, in which SAN and atrial cells are scattered throughout the SAN region with the proportion of atrial cells increasing towards the periphery. Simulation results suggest that the gradient model achieves frequency entrainment more easily than the other models of SAN heterogeneity. The gradient model also reproduces action potential waveshapes and a site of earliest activation consistent with experimental observations in the intact SAN. It is therefore proposed that the gradient model of SAN heterogeneity represents the most plausible model of SAN organisation.
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Sanders, Luke. "Pacemaker mechanisms of the guinea pig sino-atrial node." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510214.
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Edgar, Deborah Rankine. "A multiple sensor dual chamber waveform recording diagnostic pacemaker." Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363426.
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Khalid, Muhammad, Furqan Khattak, Sathvika Gaddam, Vijay Ramu, and Vipul Brambhatt. "Complete Pacemaker Lead Fracture after a Theme Park Ride." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/176.
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Fracture of a pacemaker lead is one of the most common causes of pacemaker malfunction. Lead fractures are seen in approximately 4 % of patients with pacemakers. We present a rare case of complete severance of the tip of a dual chamber pacemaker atrial lead.
A 62 years old male presented for a routine device check of his pacemaker, which was originally implanted in 2002 for sick sinus syndrome and had a generator change in 2010. Device check showed a dual chamber pacemaker with right atrial and right ventricular leads and a remaining battery life of 8.6 years. Patient was not pacemaker dependent. Ventricular lead showed normal sensing, impedance and pacing threshold. Atrial lead showed unusually high impedance of 2175 ohms and no capture on testing at voltages as high as 7.5 mV. Further evaluation was done due to abnormal atrial lead test. An EKG was obtained showing normal sinus rhythm and atrial pacing spikes with no capture. Chest X-ray revealed a complete severance and dislocation of the atrial lead tip and an intact ventricular lead. A detailed history was obtained, and patient denied any trauma to the chest or upper extremities, chest pain, shortness of breath, palpitations, syncope or presyncope. Upon further history, patient reported a recent visit to theme park and enjoying high thrill rides. On examination, there were no signs of trauma, erythema, swelling, warmth, drainage or erosion at implant site. The pacemaker setting was changed from DDDR to VVIR, with plans to cap the proximal port of the fractured lead and placing a new atrial lead.
Pacemaker lead fractures are reported with an incidence rate of 0.1 to 4.2 % per patient year [1]. The most common site of lead fracture is at the site of entry (40%) followed by between the entry site and generator (28%), close to the generator site (23%) and only (7%) are intravascular fractures [1]. Trauma and subclavian crush syndrome are the most commonly reported causes of pacemaker lead fractures. Pacemaker lead fracture due to physical exertion is an uncommon cause of lead malfunction [2]. Few cases have been reported of traumatic lead fracture due to the blunt chest trauma [3]. Patients with a lead fracture may present with symptoms of dizziness, syncope, chest discomfort, palpitations or, less commonly extra cardiac symptoms like hiccups or may completely be asymptomatic as seen in our patient. Diagnosis can be made by electrogram during device check, ECG and careful review of chest imaging such as chest x ray or fluoroscopy. Treatment is placement of a new lead with or without extraction of the fractured lead. This rare case of pacemaker lead fracture after a theme park ride indicates there may be a risk to pacemaker leads with high velocity amusement park rides which are becoming popular. This may have clinical implications such as a need for caution during amusement park visits and routine pacemaker interrogations after such visits especially in pacemaker dependent patients.
References:
1: Alt E, Völker R, Blömer H: Lead fracture in pacemaker patients. Thorac Cardiovasc Surg.1987, 35:101-4.10.1055/s-2007-1020206
2: ohm J: Displacement and fracture of pacemaker electrode during physical exertion. Report on three cases. Acta Med Scand.1972, 192:33-5.10.1111/j.0954-6820.1972.tb04774
3: Bőhm A1, Duray G, Kiss RG: Traumatic Pacemaker lead fracture. Emerg Med J.2013, 30:686.10.1136/emermed-2012-202090.
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Zhang, Xinzhao. "Simulation of cardiac pacemaker dysfunction arising from genetic mutations." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/simulation-of-cardiac-pacemaker-dysfunction-arising-from-genetic-mutations(017e8599-a29f-4e38-b3af-5a54ae460800).html.
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The sinoatrial node (SAN) is the primary pacemaker in mammalian hearts and is vital to cardiac function. Genetic mutations in SAN can result in lose-of-function of ion channels, consequently arouse sinus node dysfunction (SND), Brugada syndrome (BrS) and progressive cardiac conduction disease (PCCD). The mechanisms underlying the he pathogenesis for cardiac pacemaker dysfunctions associated with genetic mutations has not been defined. In this project, by using computer modeling, mechanisms by which the HCN4 mutations impair cardiac pacemaking and possible pro-arrhythmic effects of ivabradine were investigated. Action potential (AP) models for rabbit sinoatrial node cells were modified to incorporate experimentally reported If changes induced by HCN4 gene mutations. At both the cellular and intact SAN-atrium tissue level, If reduction due to the HCN4 mutations slowed down pacemaking. At the tissue level, these mutations compromised the AP conduction across the SAN-atrium, leading to a possible sinus arrest or SAN exit block. Moreover, vagal nerve activity could amplify the bradycardiac effects of the HCN4 gene mutations, leading to sinus arrest and SAN exit block that was not observed with the mutations or ACh alone. Similarly, SND associated with SCN5A mutations and acquired cardiac conditions were studied. 1) Mathematical models of rabbit SAN cells and 2D tissue models were modified to investigate SAN function and intracardiac conduction in a murine model of long QT syndrome type 3. A prolonged tail current INa,L was introduced and incorporated with a normal INa,T to test the SAN pacemaker function and AP conduction from the SAN to atrial septum. Simulation results showed that a combined reduction in INa,T and introduction of INa,L achieved alterations in both pacemaking rate and conduction. 2) Mathematical models of mouse SAN cells were modified to investigate the mechanisms underlies the SAN associated with SCN5A deficiency and aging. A coupled SAN-atrium cell model was developed to replicate the experimentally observed slowing of SAN conduction with aging and SCN5A-disruption The modelling studies reconstructed the physiological mechanisms by which both aging and SCN5A-disruption lead to SND, thereby drawing parallels between these and similar conduction changes in the ventricle that occur in the possibly related condition of PCCD. At last, a 2D anatomically based model of the SAN-atrium was constructed. This model successfully reproduced the effects of vagal nerve stimulation and SCN5A-E161K gene mutation on spontaneous activity of the SAN and AP conduction across the SAN-atrium.
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Hoffman, Jessica. "DEVELOPMENT OF AN ADVANCED PRACTICE NURSE-MANAGED PACEMAKER CLINIC." Thesis, The University of Arizona, 2002. http://hdl.handle.net/10150/610596.
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Nedd, Steven. "Self-diagnostics digitally controlled pacemaker/defibrillators : a design plan for incorporating diagnostics and digital control in the schema of a pacemaker/defibrillator design /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FNedd.pdf.
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Thesis (M.S. in Software Engineering)--Naval Postgraduate School, September 2005.Thesis Advisor(s): William Ray, Man-Tak Shing. Includes bibliographical references (p. 57-58). Also available online.
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Louro, César Parente. "Análise do tratamento do bloqueio atrioventricular de terceiro grau em dois gatos através da implantação de pacemaker artificial por via transdiafragmática com o elétrodo epicárdico sem suturas." Master's thesis, Universidade de Évora, 2021. http://hdl.handle.net/10174/29212.
Full textAbstract:
O bloqueio atrioventricular de terceiro grau é um distúrbio de condução elétrica
raramente diagnosticado em gatos devido à capacidade da espécie em manter um ritmo
de escape ventricular superior a 120 bpm, evitando a descompensação cardíaca e a
manifestação de sintomas. Contudo, nos casos mais severos estão descritos como
sintomas mais comuns o stress respiratório, as síncopes e pontualmente a sintomatologia
convulsiva incidiente.
Este estudo visa a análise dos tratamentos realizados no Hospital Veterinário do
Porto nos dois gatos diagnosticados com bloqueios atrioventriculares de terceiro grau de
carácter paroxístico e sintomatologia convulsiva coincidente, através da implantação de
pacemaker epicárdico sem suturas e por via transdiafragmática. Face à limitação da
amostra, os resultados obtidos permitiram concluir que a técnica selecionada assegura a
implantação célere e segura do elétrodo bem como a recuperação da qualidade de vida do
paciente devido à resolução do bloqueio e da sintomatologia convulsiva, caso seja
realizada atempadamente; Abstract:
Analysis of the treatment of third-degree atrioventricular block in two cats
with the implantation of the artificial pacemaker and the epicardial
electrode sutureless via transdiaphragmatic approach
The third degree atrioventricular block is an electrical conductive disorder rarely
diagnosed in cats due to the species' ability to maintain a ventricular escape rhythm higher
than 120 bpm, preventing cardiac decompensation and the manifestation of symptoms.
However, in the most severe cases, respiratory stress, syncope and occasionally
incidential seizures are described as the most common symptoms.
This study aims to analyze the treatments performed at the Hospital Veterinário
do Porto in the two cats diagnosed with third degree atrioventricular blocks of paroxysmal
character and coincident convulsive symptomatology, through the implantation of the
epicardial pacemaker suturless via transdiaphragmatic approach. Although the sample is
limited, the results obtained allowed us to conclude that the selected technique ensures
the rapid and safe implantation of the electrode as well as the recovery of the patient's
quality of life due to the resolution of the block and convulsive symptoms, if performed
in a timely manner.
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Ainslie, Mark Peter. "Multiparametric assessment of apical versus septal pacing study using Cardiac Magnetic Imaging." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/multiparametric-assessment-of-apical-versus-septal-pacing-study-using-cardiac-magnetic-imaging(85477e0d-bf72-4c9e-a6f0-9bd25b9cd0f1).html.
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The optimal site at which to pace the right ventricle (RV) is still unclear. This study aimed to answer this question utilising cardiac magnetic resonance imaging, which up until recently was contraindicated in pacemaker patient cohorts. The objective was to determine the effect of apical and outflow tract septal pacing on cardiac function and remodeling as assessed by MRI. In addition, physcial and psychological functional parameters were assessed. A series of sub-studies were performed as part of the research. Study 1 validated the velocity phase encoding used to determine flow measurements. This found measurements were reproducible. Study 2 and 3 focused on the method of CPEX testing in pacing dependent patients and whether a training effect was observed with the CPEX testing. It found that treadmill testing resulted in a greater heart rate response and higher VO2 max results. No significant training effect was observed. Study 4 used phantom models to determine the effect of metal susceptibility artefact on mapping and velocity encoded MR sequences. An inverse relationship between artefact and distance from the pacemaker was observed. At approximinately 10 cm from the device, artefact is negligible. Study 5 determined the best methods of image optimization in the presence of the pacemaker. T1 weighted imaging along with spoiled gradient imaging was less affected by artefact compared to late gadolinium and bSSFP imaging. Study 6 evaluated in-house developed software to measure torsion using data derived from commercial available tagging and feature tracking software. At low heart rates measures were comparable but tagging became less accurate with heart rates over 100 bpm. The main study comprised of the baseline data of 50 patients from the ongoing MAPS trial and some intermediate data after 9 months for a smaller cohort. There was not a significant difference in left ventricular volumes or ejection fraction at baseline but differences were observed in deformational indices including longitudinal strain, strain rate, twist and torsion. At 9 months a difference in ejection fraction was observed between the pacing modes along with differences in deformational parameters. Clinically significant differences were not seen between pacing positions at baseline or 9 months but the outflow tract septal position was superior based on deformational data.
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Victor, Frédéric. "Etude hémodynamique comparative de différents sites et configurations de stimulation ventriculaire." Rennes 1, 2002. http://www.theses.fr/2002REN1B057.
Full textAbstract:
La stimulation cardiaque définitive s'attache désormais en plus du traitement des bradycardies malignes à optimiser l'hémodynamique. Si l'apex du ventricule droit reste le site électif de stimulation ventriculaire, les modifications de la séquence de contraction et de relaxation alors induits, altérent les fonctions systolique et diastolique cardiaques. C'est pourquoi nous avons avons évalué deux sites de stimulation ventriculaire droite alliant facilité d'implantation et fiabilité à long terme. L'infundibulum normalise l'axe des ventriculogrammes. Le septum normalise l'axe et réduit significativement la durée des ventriculogrammes.
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McGurk, Shelly Lynn. "Evaluation of the Safety of MRI Scanning of Patients with MR Conditional Pacemakers." ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/4009.
Full textAbstract:
Magnetic resonance imaging (MRI) of patients with cardiac implantable electronic devices (CIED) has been associated with risks such as device/lead movement, device dysfunction, and lead heating. New technological advancements have made it possible for MRI to be safely performed when adhering to an evidence-based protocol; however, this practice has not yet been widely adopted. The purpose of this practice-focused question project was to examine the safety of MRI as a diagnostic modality for the aggregate population of adult patients with MR conditional pacemakers when a nurse-practitioner-led, evidence-based protocol was used. The Iowa model served as the guide for implementation of the program, and the Donabedian framework was used to evaluate the program through process, structure, and outcomes. Evidence was obtained through a documentation template that served as the procedural record in the electronic health record. Demographic information, program fidelity, and manufacturer adherence were analyzed through descriptive statistics. Clinical outcomes related to device function were measured pre- and post- MRI and analyzed with chi square and paired t-test inferential statistics to determine if statistically significant change occurs in the setting of MRI scanning. According to data analysis of 34 studies, there were no statistically significant changes in lead impedance, pacing thresholds, or patient reported symptoms pre- and post- MRI. The pilot program has been recommended for organizational adoption and will increase the scope of advanced practice nurses within the organization and provide the CIED aggregate population with access to an important diagnostic modality.
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Kanani, Sandra. "l'utilisation des cellules souches pour créer une pacemaker cardiaque biologique." Phd thesis, Université de Nice Sophia-Antipolis, 2005. http://tel.archives-ouvertes.fr/tel-00175655.
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En étudiant des modèles de cellules souches, nous avons montré que l'induction des oscillations dans des myocytes ventriculaires normaux inexcitables n'est pas possible en les connectant à des cellules souches. Jusqu'à aujourdhui, cette induction n'a jamais été démontrée même sous de bonnes conditions. Les résultats référencés [5],[4] ne font apparaître qu'une augmentation de la fréquence d'oscillation (soit dans les cellules en culture, soit dans le coeur).Les oscillations ne deviennent possibles que pour les myocytes qui ont un seuil d'excitation des oscillations induites bien plus bas que la normale. Seules les méthodes qui diminuent le niveau d'expression de courant IK1 donnent des résultats.
Il existe une autre approche, qui consiste à ne pas connecter directement les cellules souches à des myocytes, mais à d'autres types de cellules cardiaques avec un seuil d'excitation très bas. De cette façon, des oscillations sont induites sans avoir à modifier le courant IK1 . Ces cellules transitoires pourront être des cellules AV node, de Purkinje ou des cellules voisinant SA node.
Pour amener un tissus cardiac à oscillation, les pacemakers artificiels de petite taille exigent des courants d'une magnitude bien plus élevée que dans les expériences menées avec des paires de cellules ou des cultures. Pour éviter ce problème, la taille des pacemakers artificiels doit être plus grande que la constante électrotonique ?
Pour le courantpacemaker, la plupart des expérimentateurs ont l'habitude de ne mesurer que l'inactivation. Cette seule mesure ne suffit pas pour étudier les oscillations. Les définitions incluant à la fois inactivation et activation du courant pacemaker doivent prévaloir contrairement à la tradition dans le domaine.
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Bongiovanni, Giorgia. "L'evoluzione della stimolazione cardiaca: dai pacemaker tradizionali alla tecnologia leadless." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
La stimolazione cardiaca nasce attorno agli anni ‘30 con pacemaker artificiali esterni e ingombranti. Questo concetto è arrivato fino ad oggi a seguito di progressi nel design, nella complessità e nella longevità del dispositivo. Nonostante questi miglioramenti, gli attuali pacemaker transvenosi hanno un tasso di complicanze fino al 12.5% legate alla necessità di una tasca chirurgica per il generatore, elettrocateteri permanenti nel sistema vascolare e il passaggio degli stessi attraverso la valvola tricuspide. Per affrontare questi problemi è stato proposto il concetto di pacemaker intracardiaco completamente autonomo, ossia senza elettrocateteri e senza necessità di un generatore di impulsi pettorali, aggirando così le principali fonti di complicanze del pacemaker transvenoso. La realizzazione clinica di questo concetto è stata raggiunta nel 2012 grazie ai progressi tecnologici nella longevità delle batterie, nelle tecnologie di comunicazione e nei sistemi di rilascio transcatetere. Al momento sono state sviluppate due varianti di pacemaker leadless in grado di svolgere una stimolazione monocamerale VVI: il pacemaker LCP Nanostim e il sistema di stimolazione transcatetere TPS Micra. Entrambi questi dispositivi sono simili come forma e dimensioni ad una convenzionale pila alcalina microstilo e forniscono il trattamento per bradiaritmie cardiache senza l’impiego di cateteri transvenosi, essendo totalmente impiantabili nel ventricolo cardiaco destro. La tecnologia leadless risulta essere una promettente e attuabile opzione per la stimolazione cardiaca permanente, con eccellenti risultati clinici e ancora molto potenziale per ridurre le complicanze dei sistemi tradizionali. L’unica grande limitazione con cui si trovano a combattere riguarda la modalità di stimolazione monocamerale VVI, ma a ciò si sta cercando di ovviare tramite studi su tecniche di comunicazione wireless tra più dispositivi al fine di poter fornire una terapia bicamerale.
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Liang, Huamin. "Ionic mechanisms underlying pacemaker activity in the murine embryonic heart /." Köln, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000264348.
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Wang, Kai. "Structure-function and physiological properties of HCN-encoded pacemaker channels." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39557273.
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Wang, Kai, and 王凱. "Structure-function and physiological properties of HCN-encoded pacemaker channels." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39557273.
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ALBA, CATHERINE. "Reaction cutanee granulomateuse apres la mise en place d'un pacemaker." Toulouse 3, 1993. http://www.theses.fr/1993TOU31070.
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Piron, Julien. "Création d'un pacemaker biologique cardiaqueRégulation physiologique du canal KCNQ1/KCNE1." Nantes, 2008. https://archive.bu.univ-nantes.fr/pollux/show/show?id=f8628856-3a58-4486-9bbc-fb4d58c85804.
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Chez des souris en bloc auriculo-ventriculaire (BAVc), nous avons créé un pacemaker biologique cardiaque grâce à un vecteur non-viral. Cinq jours avant l'obtention du BAVc par ablation du faisceau de His, les plasmides codant le canal ionique HCN2 responsable du courant de pacemaker, If, et le récepteur β2-adrénergique, sont mélangés au vecteur tétronic 304 et injectés dans la paroi du ventricule gauche. Le rythme d'échappement ventriculaire des souris HCN2-Adrb2 est significativement plus rapide que celui des souris sham et est stabilisé jusqu’à 40 jours. Ce pacemaker biologique est régulé par la stimulation sympathique et permet d’augmenter la survie des souris. Le PI(4,5)P2 régule l’activité du canal KCNQ1-KCNE1, responsable du courant potassique IKs, en stabilisant l’état d’ouverture du canal. De très nombreuses mutations du canal KCNQ1 sont responsables du syndrome du QT long à l’origine de troubles du rythme cardiaque. Nous avons démontré que l’implication de trois formes mutantes de KCNQ1 (R243H, R555C et R539W) dans le syndrome du QT long, s’explique par une diminution de l’affinité de KCNQ1 pour le PIP2. L’osmosensibilité du canal KCNQ1 est une voie physiologique prépondérante de la réponse des cellules cardiaques aux variations osmotiques. La caractérisation des réponses aux variations d’osmolarité du canal KCNQ1-KCNE1 et des trois canaux mutants caractérisés par une faible affinité pour le PIP2, suggère que l’osmosensibilité de KCNQ1-KCNE1 ne passe par l’étirement de la membrane plasmique mais implique une variation du volume cellulaire provoquant une régulation de la concentration de Mg2+, et donc une variation du PIP2 disponibleIn a mouse model of complete atrioventricular block (CAVB), we generate a functional ventricular pacemaker by non-viral gene delivery. Five days before catheter-mediated radiofrequency His bundle ablation, plasmids coding cyclic nucleotide-gated HCN2 channel (Hcn2), responsible for the pacemaker current, If, and the ß2-adrenergic receptor (Adbr2), are mixed with the tetronic 304 vector and injected in the wall of the left ventricle. The escape ventricular rhythm in HCN2-Adrb2 mice is significatively faster than in sham mice and is stabilized until 40 days. This biological pacemaker is regulated by sympathetic input, and improves life expectancy in this mouse model of CAVB. PI(4,5)P2 regulates KCNQ1-KCNE1 potassium channel activity, which underlies the potassium current IKs, by stabilizing the open state of the channel. Various mutations of the KCNQ1 channel are responsible for the long QT syndrome, characterized by cardiac arrhythmias. We demonstrated that the involvement of three mutant forms of KCNQ1 (R243H, R555C and R539W) in the long QT syndrome, can be explained by a reduced PIP2 affinity of KCNQ1 channels. The osmosensitivity of KCNQ1 channel is of physiological relevance in cardiac cells in response to osmotic variations. The characterization of the response to osmotic variations of the wild-type and three mutant KCNQ1-KCNE1 channels characterized by a weak PIP2 affinity, suggests that the osmosensibility of KCNQ1-KCNE1 does not involve membrane stretching but a variation of the cellular volume provoking a variation of the Mg2+ concentration, and thus a regulation of available PIP2
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Hawkins, Rodney J. "EPICARDIAL WIRELESS PACEMAKER FOR IMPROVED LEFT VENTRICULAR RESYNCHRONIZATION (CONCEPTUAL DESIGN)." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/431.
Full textAbstract:
The human body is a well tuned mechanism where systems work in synergy to provide a healthy quality of life. The human circulatory system transports oxygenated blood from the heart to the rest of the body delivering the proper nutrients for cells to function. When the heart malfunctions, serious complications can arise leading to sudden cardiac arrest. Congestive heart failure (CHF) is one heart disease that affects the synchrony of the heart’s ventricles.
Cardiac resynchronization therapy (CRT) has been widely accepted as a treatment for CHF. Similar to traditional dual chamber pacing techniques, CRT adds a pacing lead to stimulate the left ventricle. Left ventricular leads are implanted via the coronary sinus which provides the easiest surgical access to the left ventricle. Another option for LV pacing is by using an epicardial lead. This option has proven to be safe and effective but requires major surgery. An epicardial lead is usually implanted by performing a thoracotomy. Many studies have been done to show the benefits of bi-ventricular pacing, therefore developing new methods to gain LV access safely and reliable are highly desirable.
The epicardial satellite pacemaker, or EPI pacemaker, is a component of a larger CRT system. This implantable cardiac system is composed of a master pacing unit with leads and a remote satellite pacing unit. The master unit is a traditional CRT device electrically coupled to the right side of the heart. It controls the right atrium and ventricle via transvenous leads anchored to the endocardium of the heart. The master device generates the pacing pulses to stimulate the right atrium and right ventricle and a communications module to transmit pacing commands to the epicardial satellite device. The epicardial satellite pacemaker is a leadless device mounted directly on the epicardium of the left ventricle. The epicardial pacemaker can be implanted using a thoracoscopic procedure during implant of the master unit. In special events, it can be implanted using prophylactic techniques during heart bypass surgery of other surgical procedures where access to the heart is available. Much work needs to be done to prove the technology. But current RF communication capabilities in today’s devices offer the groundbreaking path to develop a satellite LV pacing design.
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Ng, Leo Chun Ting. "Molecular mechanism of cyclic nucleotide action on HCN pacemaker channels." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57686.
Full textAbstract:
HCN pacemaker channels generate the “funny” current that is responsible for initiation and regulation of electrical activity in the heart and the nervous system. Activated near resting membrane potentials, the channel conducts a net inward current that maintains action potential. The direct binding of cyclic AMP upon adrenaline release also enhances channel opening, leading to an increased frequency of action potential. The cytoplasmic cAMP-binding domain is coupled to the C-linker found between the binding domain and the transmembrane domain, subsequently triggering the opening of the pore. Despite extensive research, the mechanism that links the binding event to channel facilitation is still unclear. In this thesis, we looked into the different aspects of the missing link. In addition to basic understanding, the significance of learning about HCN channel modulation by cAMP is that there may be therapeutic advantage of controlling heart rate via drug interaction with the cyclic nucleotide binding pocket. Using the isolated C-linker/binding domain, we pinpointed residues in the binding pocket that contribute to strong affinity and ligand specificity by single residue alanine-scanning and isothermal titration calorimetry for measurement of binding affinity. By comparing our binding data to functional measurements of potency in full-length channels containing the same single substitutions, we found that two residues, L633 and I636, reduced potency more severely than affinity when mutated, and proposed that these residues are involved in a post-binding transition event. We also found that two partial agonists, cCMP and cIMP, bound to the canonical site, but failed to fully promote tetrameric gating ring which is found on the inner side of the pore and hypothesized to facilitate its opening. We proposed that the weakened interactions between the partial agonists and the C-helix of the binding domain limit the formation of the gating ring and led to reduced facilitation of opening in the full-length channel. Finally, we elucidated the mechanism behind two disease-associated mutations found in the cytosolic C-linker/binding domain portion of the HCN2 and HCN4 channels to gain a better understanding of how they influence cAMP binding and channel opening, and cause epilepsy and profound bradycardia, respectively.Medicine, Faculty of
Graduate
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Gomes, Nuno Miguel Prata. "Concepção e teste de eléctrodos para pacemaker de estimulação diafragmática." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11043.
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Dissertação para obtenção do Grau de Mestre em Engenharia BiomédicaExistem actualmente diversos mecanismos de ventilação artificial que, ao funcionarem a pressão positiva, forçam a entrada de ar para dentro dos pulmões, apresentando-se como a principal forma de ventilação utilizada. Existem ainda outras alternativas no que toca a promover a respiração artificial, nomeadamente estimulação do nervo frénico por eléctrodos, com a consequente contracção do diafragma; contudo, estes acabam por provocar irritação ou mesmo lesões na pele e no próprio nervo frénico ou, em casos extremos, conduzir a arritmias cardíacas. A insuficiência respiratória apresenta-se principalmente como consequência de patologias do foro respiratório, por exemplo a doença pulmonar obstrutiva crónica. Nesta, existem trocas inadequadas de gases no sistema respiratório, existindo uma incapacidade de manter os níveis normais de oxigénio e dióxido de carbono. O trabalho desenvolvido incidiu sobre o desenho e construção de um protótipo de eléctrodos de estimulação diafragmática e encontra-se inserido noutro mais vasto, que teve por objectivo a construção de um pacemaker diafragmático fisiológico. Para a execução do trabalho foi necessária a consolidação de conhecimentos na área da fisiologia respiratória e engenharia biomédica. De modo a atingir os objectivos propostos foram construídos diversos eléctrodos de estimulação, com diversos materiais e formas, sendo efectuada uma modulação constante do sinal, tentando que a respiração fosse o mais semelhante possível à respiração fisiológica normal. Para a escolha dos materiais a utilizar na construção destes eléctrodos, foi tida em conta a sua condutibilidade, maleabilidade e biocompatibilidade, uma vez que estes eléctrodos serão implantados na superfície diafragmática. Nesse âmbito tiveram-se, também, em atenção a forma e localização relativa dos eléctrodos na superfície diafragmática. Para isso foi feito o mapeamento eléctrico do diafragma e foram simulados diferentes sinais para a sua estimulação eléctrica. Numa segunda fase, trataram-se as combinações de forma, localização e estimulação eléctrica mais favoráveis em modelos animais; tendo sido testados eléctrodos de cobre, alumínio, estanho e latão. Foram obtidos resultados compatíveis com o padrão de ventilação normal. No entanto diversos assuntos ficaram por explorar, nomeadamente a difícil adesão dos eléctrodos à musculatura diafragmática e aumento do tempo de ventilação útil, uma vez que a fadiga diafragmática impedia a contracção eficaz do mesmo ao fim de algum tempo.
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Brosché, Tove, and Bianca Kalajdzic. "Patienters upplevelser av att vara vaken under operation när pacemaker anläggs." Thesis, Högskolan i Halmstad, Sektionen för hälsa och samhälle (HOS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-24369.
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Det är en unik upplevelse att bli opererad med lokalanestesi och vara vaken under ett operativt ingrepp. Patienten överlämnas till vårdpersonalen och är beroende av deras omhändertagande och kunskap. Kontinuerlig information under ingreppet samt ett gott bemötande från personalen kring patienten är avstor vikt för att skapa en trygg miljö och ge god omvårdnad. Syftet med studien var att beskriva patienters upplevelse och känslor av den perioperativa omvårdnaden när de var vakna under ett operativt ingrepp. Fyra intervjuer med konsekutivt utvalda patienter som genomgått operationen på sjukhus i sydvästra Sverige inkluderades i studien. Öppna, övergripande frågor samt följdfrågor användes under intervjuerna. Kvalitativ innehållsanalys användes. Analysen ledde till tre kategorier; tidigare upplevelser av vården, omvårdnad kring operationen samt känslor som uppstod under operationen. Tidigare erfarenhet samt personalens omvårdnad gav trygghet i de aktuella operationerna. Känslorna som uppstod under en vaken operation var både positiva och negativa. Resultatet kan bidra tillvidare utveckling och förbättring av den perioperativa omvårdnaden kring envaken patient.Being awake during surgery is a unique experience. The patient is handed over to the nursing staff and is dependent on their care and knowledge. Continuous information during surgery and professional care from the nursing staff is important to create a safe environment and provide good healthcare. The aim of the study was to describe the patient’s experience and feelings of the perioperative nursing care when being awake during surgery. Four interviews with consecutively selected patients who had undergone surgery in a hospital in the south west of Sweden were included. Open, general questions and supplementary questions were used during the interviews. Qualitative content analyz was used. The analyz resulted in three categories: past experiences of care, care during the surgery and feelings that occurred during the operation. Previous experience and the care provided by the nurses gave patients the feelings of security. Both negative and positive feeling occurred during surgery. The results may contribute to further development and improvement of the perioperative nursing care on patients that are awake during surgery.
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Featherstone, Neil Christopher. "Physiology of the Pulmonary Pacemaker : A New Regulator of Lung Growth." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.507515.
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Dixon, Rose Ellen. "The role of interstitial cells of Cajal in oviduct pacemaker activity." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3369581.
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Emmer, Sawyer Franklin. "Development of a clinically relavent biological pacemaker for the pediatric population." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12358.
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Thesis (M.A.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Electronic pacemakers have been instrumental in saving the lives of pediatric patients who are either born with or acquire an irregular heartbeat or a blocked conduction system. Although the current pacing model has saved the lives of many children, the associated negative side effects have exacerbated the need for a biological alternative. This thesis will present various ways that researchers have generated spontaneously active cardiac tissue. Laboratories across the country have formulated unique ways to generate such a node through gene and/or cell-based approaches. Following many years of experiments in animal models, cardiac researchers are currently assessing the positive aspects and drawbacks of each method in order to find the best way to generate a safe, long lasting, and financially practical biological pacemaker. Although a great deal of progress has been made on the development of a bioengineered spontaneously active node, there remains a need for more analysis of each model before they are tested in humans. Scientists have conducted preliminary, proof-of-concept experiments which have given pediatric patients, their families, and physicians hope for a biological alternative in the future. With every novel experiment, the scientific community is getting closer to creating an biological alternative that will last a lifetime, grow with the patient, and respond to adrenergic stimuli. Hopefully, when a biological pacemaker has been developed and tested, this extensive research will vastly improve the quality of life of arrhythmic pediatric patients.
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Kanani, Sandra. "Stem cells as gene delivery system to create cardiac biological pacemaker." Nice, 2005. http://www.theses.fr/2005NICE4104.
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En étudiant des modèles de cellules souches, nous avons montré que l'induction des oscillations dans des myocytes ventriculaires normaux inexcitables n'est pas possible en les connectant à des cellules souches. Jusqu'à aujourd'hui, cette induction n'a jamais été démontrée même sous de bonnes conditions. Les résultats référencés ne font apparaître qu'une augmentation de la fréquence d'oscillation (soit dans les cellules en culture, soit dans le coeur). Les oscillations ne deviennent possibles que pour les myocytes qui ont un seuil d'excitation des oscillations induites bien plus bas que la normale. Seules les méthodes qui diminuent le niveau d'expression de courant I_K1 ou augment le niveau d'expression de courant I_Ca donnent des résultats. Il existe une autre approche, qui consiste à ne pas connecter directement les cellules souches à des myocytes, mais à d'autres types de cellules cardiaques avec un seuil d'excitation très bas. De cette façon, des oscillations sont induites sans avoir à modifier le courant I_K1. Ces cellules transitoires pourront être des cellules AV node, de Purkinje ou des cellules voisinant SA node. Pour amener un tissus cardiac à oscillation, les pacemakers artificiels de petite taille exigent des courants d'une magnitude bien plus élevée que dans les expériences menées avec des paires de cellules ou des cultures. Pour éviter ce problème, la taille des pacemakers artificiels doit être plus grande que la constante électrotonique λ. Pour le courant pacemaker, la plupart des expérimentateurs ont l'habitude de ne mesurer que l'inactivation. Cette seule mesure ne suffit pas pour étudier les oscillations. Les définitions incluant à la fois inactivation et activation du courant pacemaker doivent prévaloir contrairement à la tradition dans le domaineBy investigating stem cell models, we showed that induction of oscillation in normal ventricular myocytes by connecting stem cells to them is not possible. Induction of oscillations by stem cells has not been demonstrated yet, in well controlled conditions. Reported results demonstrate only increase of oscillation frequency (in cell culture or in whole hearts). Oscillations become possible only for myocytes with a much lower than normal threshold for inducing oscillations. Approaches like decreasing of expression level of I_K1 current or increasing I_Ca current in myocytes are successful. Another possible approach is connecting stem cells not directly to myocytes but to other types of cardiac cells with a lower oscillation threshold. This induces oscillation without any need to affect I_K1, I_Ca current. These transitional cells might be AV node cells, Purkinje cells or cells in the vicinity of the sinus node. To drive cardiac tissue, small size artificial pacemakers need to deliver currents orders of magnitude larger than those used in cell pair or cell culture experiments. To avoid this, the size of the pacemaker created should be several times larger than the electrotonic constant λ. For pacemaker currents, most experimenters traditionally measure only inactivation. A description of a stem cell including inactivation only, is not precise enough to study oscillations. A description including both, activation and inactivation of the pacemaker current should be used, contrary to tradition in this field
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Arora, Samarth. "Low Power Hybrid CMOS-NEMS for Microelectronics: Implementation in Implantable Pacemaker." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1310676370.
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Skoglund, Aline, and Kelly Thai. "Omvårdnadsbehov hos patienter som lever med implanterbar hjärtstimulator." Thesis, Högskolan i Halmstad, Akademin för hälsa och välfärd, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-43515.
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Bakgrund: Idag lever många med kardiovaskulära sjukdomar framförallt hjärtarytmier och / eller hjärtstillestånd vilket är en av de vanligaste dödsorsakerna globalt. En hjärtstimulator vars funktion är att stimulera hjärtat till att återgå till en normal hjärtfrekvens. Personer som lever med en implanterbar hjärtstimulator upplever rädsla, oro och ångest relaterat till vardagen då man fruktar för elektriska störningar eller enhetsfel. En personcentrerad omvårdnad är viktig då det underlättar för patienter att leva ett normalt liv som möjligt.Syftet: Syftet med litteraturstudien var att belysa omvårdnadsbehov i form av stöd hos patienter som lever med implanterbar hjärtstimulator. Metod: En litteraturstudie med induktiv ansats och kritisk granskning av 11 artiklar. Resultat: Resultatet delas in i tre teman: Iformation, socialt och professionellt stöd samt Kontinuerlig uppföljning. Information skapar större förståelse samt trygghet hos patienter. Stöd från omvårdnaspersonal och närstående ökade förmågan av sjävlkännedom och självskänsla. Kontinuerliga uppföljningar förbättrade fysiska och psykologiska faktorer, som ökade livskvaliteten. Slutsats: I studien framkom det att information, stöd och kontinuerliga uppföljningar var av stor betydelse för den personcentrerade omvårdnaden. Studien redogör att utterligare kunskaper behövs inom sjuksköterskeprofessionen för att berdiva en god vård- och omsorg.Background: Today many people live with cardiovascular disease, especially cardiac arrhythmias and / or cardiac arrest, which is one of the most common causes of global death. A pacemakers function is to stimulate the heart to return to a normal heart rate. People who live with an implantable cardiac stimulator experience fear, concerns and anxiety related to electrical disturbances and device error in everyday life. Person-centered nursing is important as it makes it easier for patients to live a normal life as possible. Purpose/aim: The aim of the literature study was to highlight the nursing needs in the form of support in patients living with the implantable cardiac defibrillator. Method: A literature study using an inductive approach and 11 articles was critically reviewed. Result: The results are divided into three themes: Information, social and professional support and Continuous follow-up. Information created greater understanding and safety for the patient. Support from nursing staff and relatives increased the ability of self-awareness and self-esteem. Continuous follow-up improved physical and psychological factors that increased the quality of life. Conclusion: The findings of the study were that information, support and continuous follow up were of great importance concerning person-centered nursing. The study reports that additional knowledge is needed in the nursing profession to be able to conduct good care and nursing.
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Lei, Ming. "Electrophysiological studies of rabbit isolated sino-atrial node cells." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360375.
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Yılmaz, Ayten. "Studies on cardiac pacing emphasis on pacemaker sensors and cardiac resynchronization therapy /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2005. http://dare.uva.nl/document/79548.
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Conti, Riccardo. "Studio e realizzazione di un "timing circuit" e "output circuit" per pacemaker." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9264/.
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Nell'elaborato è stato svolto uno studio su più livelli degli elementi essenziali del pacemaker asincrono secondo la realizzazione circuitale proposta da Wilson Greatbatch nel 1960. Un primo livello ha riguardato l’analisi teorica del circuito. Un secondo livello ha riguardato un’analisi svolta con LTSPICE. Con questo stesso programma, si è analizzato il segnale di temporizzazione e la forma d’onda sul carico al variare del valore di alcuni componenti chiave del circuito. Infine, si è proceduto alla sua realizzazione su breadboard.