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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Outcome of Stroke Prevention : Analyses Based on Data from Riks-Stroke and Other Swedish National Registers

Åsberg, Signild January 2012 (has links)
The aim of this thesis was to explore variations in stroke prevention and the effect of prevention on outcome. The studies were based on patients registered in the Swedish Stroke Register between 2001 and 2009 and although used to different extents in each paper, additional information was retrieved through linkage to The National Patient Register, the Cause of Death Register, the Prescribed Drug Register and the Total Population Register. Cardiovascular risk factors were prevalent among ischemic stroke (IS) patients; however, they were not always prescribed the drugs recommended, and increasing age was an important negative predictor (Paper I). After IS, the rate of hemorrhage in patients prescribed antiplatelet agents (2.4 per 100 person-years) was double to results from randomized controlled trails, but was similar for patients prescribed warfarin (2.5 per 100 person-years).  Age ≥75 years and previous hemorrhage were associated with a moderately increased risk of future hemorrhage (Paper II). Among IS patients with atrial fibrillation, one-third was prescribed warfarin and two-thirds were prescribed antiplatelets. After adjustment for a propensity score (used to adjust for the non-randomized design), warfarin was associated with a reduced risk of death (0.67; 95% CI, 0.63-0.71) (Paper III). The rate of subsequent hemorrhagic stroke was 0.4 per 100 person-years and the risk did not change (HR 1.04; 95% CI, 0.73-1.48) when later years of the 2000s (inclusion period 2005-8: follow-up until 2009) was compared with earlier years (inclusion period 2001-4: follow-up until 2005) (Paper IV, cohort). Although the risk of first-ever hemorrhagic stroke more than doubled with warfarin than without, the risk did not change between 2006 and 2009 (Paper IV, case-control). In summary, the prescription of secondary preventive drugs varies with age, even though cardiovascular risk factors are prevalent in all ages. The risk of death and hemorrhage are affected by the type of antithrombotic prescribed. Therefore, it is important individual’s stroke and bleeding risks in stroke prevention are assessed.
122

Communication Patterns in Consultations Between Patients with Atrial Fibrillation and Health Professionals

Siouta, Eleni January 2012 (has links)
Background Patients’ preferences, needs and desires are important when discussing treatment. In consultations between patients with atrial fibrillation (AF) and health professionals, knowledge, understanding and insight about communication patterns are of vital importance for strengthening patient involvement in decision-making about their care and treatment. Aim The general aim of this thesis was to describe communication patterns in consultations between patients with AF and health professionals. Specific aims (1) To describe (i) the topics patients with AF and their nurses and physicians discuss; (ii) the use of discursive space in consultations between these participants; and (iii) the frequencies with which patients and nurses/physicians introduce the identified topics. (2) To describe the types of patient resistance to accepting treatment with warfarin and how cardiologists respond to such resistance. Methods An inductive design was used. In study I, the sample consisted of 23 consultations between patients with AF (13 women and 10 men) and health professionals (5 women and 5 men) who were employed in six different cardiologic outpatient clinics. Content analysis was used to obtain a description of topics discussed. The patterns of dominance for the various topics and participant were explored from the framework of an analysis of dominance (I). In study II, the sample consisted of 11 consultations between patients with AF (7 women and 4 men) and cardiologists (2 women and 3 men). Conversation analysis was used to describe interactions concerning resistance to treatment with warfarin. Findings Study I. Four topics were introduced by both nurses and physicians during the consultations. These were “pathophysiology”, “treatment”, “diagnostic procedures”, and “activity”. In the nurse–patient consultations an additional topic, “routines related to the physician’s responsibilities”, emerged. With respect to the number of words and turns, the distribution of the discourse space was almost equal between nurses and patients, and unequal between physicians and patients. The patients were the dominant initiators of the topic “activity”, which refers to adaptation of activities in daily life in relation to AF. Study II. There were four types of patient resistance to accepting treatment with warfarin. These included “Giving reasons for their resistance”, “Suggesting other treatment options”, “Stating treatment preferences” and “Questioning or challenging the cardiologist’s treatment recommendations”. The cardiologists’ responses to the patients’ resistance included “Repeating the treatment recommendation”, “Negotiation with the patient”, “Providing additional information about the recommended treatment” and “Extending their explanation of the purpose of the treatment”. Conclusions The medical-driven agenda dominated over the patient-driven agenda in consultations between health care professionals and patients with AF. During conversations in consultations with nurses, the patients initiated discussion of living with AF and were more talkative than they were with physicians. An awareness of types of patient resistance to treatment would enable cardiologists to consider patients’ experience-based views about their treatment;
123

Biocompatible circuits : inflammation and soluble adhesion molecules after cardiopulmonary bypass

Marcoux, Jo-Anne Éloria 11 July 2011
ABSTRACT In the modern era, the most common post-operative complications following cardiopulmonary bypass (CPB) are neurocognitive deficits (NCD) and atrial fibrillation (AF). Both morbidities have been linked to inflammation resulting from surgery, anesthesia and CPB. Microemboli, inadequate oxygen delivery and the inflammatory response consequent to blood contacting artificial components of the CPB circuit have all been linked to postoperative NCD and to a lesser extent post-operative AF. The artificial components of the CPB circuit consist of stainless steel, polyvinylchloride (PVC), polycarbonate and other carbon-based plastics. In order to attenuate the negative sequelae of blood-circuit contact related inflammatory response, industry developed the biocompatible circuit (BCC) coating for the disposable CPB circuits. Four such coatings were studied and compared to an uncoated control group in a total of 101 patients undergoing routine CPB-assisted cardiac surgical procedures. Soluble adhesion molecule (SAM) activation was studied at different time points and common clinical outcomes such as white blood cell activation, serum renal function parameters urea and creatinine, postoperative bleeding, transfusion requirements, intensive care and hospital length of stay, CPB pump volume balances, changes in weight, postoperative serum lactate and glucose and the development of AF postoperatively, were compared. Additionally, postoperative neurocognitive testing was performed using a simple bedside neurocognitive test called the antisaccadic eye movement test. The patients in all groups were tested for comparison preoperatively and 72 hr postoperatively. Results: The mandate of BCC coating development and manufacture is to attenuate the well-documented and demonstrated inflammatory response consequent to the contact of blood with artificial CPB surfaces. The studied BCCs significantly decreased platelet transfusions in females. In addition, the BCCs decreased the concentrations of 2 SAMs when measured 6 hours after surgery and CPB. The difference in SAM expression seen between the coated and uncoated groups at 6 hr was no longer apparent at 72 hr. Very little difference was noted between the four BCC groups. Patients who developed AF postoperatively seemed predisposed to do so as the serum levels of soluble vascular cell adhesion molecule was significantly higher at baseline and remained so at 6 and 72 hr. The decreased platelet transfusions in females resulting from BCC use is a highly significant finding within this high-risk group of patients. As most platelet transfusions occur soon after the patient is disconnected from CPB, the short-term decrease in SAM activation can be linked to this improved clinical finding. The studied BCC coatings have achieved limited success in their intended mandate to attenuate inflammatory response in terms of improved clinical and laboratory desired outcomes.
124

New Risk Markers in Atrial Fibrillation

Hijazi, Ziad January 2013 (has links)
Atrial fibrillation (AF) confers an independent increased risk of stroke and death. The stroke risk is very heterogeneous and current risk stratification models based on clinical variables, such as the CHADS2 and CHA2DS2VASc score, only offer a modest discriminating value. The aims of this thesis were to study cardiac biomarkers, cardiac troponin and natriuretic peptides e.g. N-terminal prohormone-B-type natriuretic peptide (NT-proBNP), and describe levels in AF patients, investigate the association with stroke or systemic embolism, cardiovascular event, major bleeding and mortality, and to assess how levels of cardiac biomarkers change over time. Cardiac troponin was analyzed with contemporary assays and high sensitivity assays. The study populations consisted of patients with atrial fibrillation and one risk factor for stroke included in the RE-LY (n=6189) and the ARISTOTLE (n=14892) biomarker substudies. Median follow-up time was 2.2 years and 1.9 years, respectively. In a subset of participants (n=2514) data from repeated measurements was available at three months. Cardiac troponin was detectable in 57.0% with the contemporary assay and 99.4% with the high sensitivity assay. NT-proBNP was elevated in approximately three quarters of the participants. In Cox models adjusted for established risk factors the cardiac biomarkers levels was independently associated with stroke or systemic embolism, cardiovascular events, and mortality. Only cardiac troponin was associated with major bleeding. In ROC analyses the prediction of stroke or systemic embolism, cardiovascular events, and mortality increased significantly by addition of cardiac troponin or NT-proBNP to the models. Persistent detectable cardiac troponin (contemporary assay) and elevated NT-proBNP levels were found in a large number of participants. Persistent detectable or elevated levels conferred significantly higher risk for stroke or systemic embolism, cardiovascular events, and mortality. By using both cardiac biomarkers simultaneously the risk stratification improved even further for all outcomes. In conclusion the analyses for the first time display that elevation of troponin I and NT-proBNP are common in patients with AF and independently related to increased risks of stroke, cardiovascular events and mortality. Persistent elevation of troponin and NT-proBNP indicate a worse prognosis than transient elevations or no elevations of either marker. The cardiac biomarkers added substantial improvements to existing risk stratification models.
125

Früh- und Langzeitergebnisse der chirurgischen Vorhofflimmerablation mittels verschiedener Energiequellen begleitend zur koronaren Bypass-Operation

Badel, Kristin 02 October 2013 (has links) (PDF)
Die hier vorliegende Studie stellt die Früh- und Langzeitergebnisse der chirurgischen Vorhofablation zur Behandlung des ischämischen Vorhofflimmerns (VHF) in Kombination mit einer aortokoronaren Bypass-Anlage vor. Dabei wurden die epikardiale Pulmonalvenenisolation mittels Radiofrequenzenergie (RF) und die endokardiale Kryoablation inklusive einer Box-Läsion und Mitralisthmuslinie miteinander verglichen. Im Zeitraum von 2002 bis 2009 wurden die prä- und postoperativen Daten von 262 Patienten mit paroxysmalem oder lang-persistierendem VHF prospektiv erhoben und anschließend eine Nachbeobachtung von durchschnittlich 2,30 Jahren durchgeführt. Die Kryoablation war im Vergleich zur RF-Ablation mit einer signifikant höheren perioperativen Invasivität und Morbidität verbunden. Die Operations- und Ischämiezeit sowie die postoperative intensivmedizinische Betreuung waren nach der Kryoablation signifikant länger. Die Rate an Schrittmacherimplantationen (4,8 % vs. 0,0 %), kardialen bzw. zerebralen Komplikationen (22,9 % vs. 12,3 %) und die Krankenhausmortalität (8,4 % vs. 2,2 %) lagen ebenfalls signifikant höher. Hingegen waren die Langzeitergebnisse ohne signifikante Unterschiede zwischen den Ablationsmethoden. Sowohl das Überleben (81,9 % vs. 86,0 %) als auch die Konversionsrate in den Sinusrhythmus (55,6 % vs. 61,5 %), die Lebensqualität der Patienten und die Komplikations- und Reinterventionsraten zeigten im Langzeitverlauf vergleichbare Ergebnisse. Auf der Basis der oben erhobenen Befunde kann die endokardiale Kryoablation nicht als Standardverfahren zur Therapie des paroxysmalen und lang-persistierenden ischämischen VHFs begleitend zu einer aortokoronaren Bypass-Anlage empfohlen werden. Die epikardiale RF-Ablation ist hier aufgrund der geringeren operativen Invasivität bei vergleichbaren Früh- und Langzeitergebnissen der endokardialen Ablation vorzuziehen.
126

Biocompatible circuits : inflammation and soluble adhesion molecules after cardiopulmonary bypass

Marcoux, Jo-Anne Éloria 11 July 2011 (has links)
ABSTRACT In the modern era, the most common post-operative complications following cardiopulmonary bypass (CPB) are neurocognitive deficits (NCD) and atrial fibrillation (AF). Both morbidities have been linked to inflammation resulting from surgery, anesthesia and CPB. Microemboli, inadequate oxygen delivery and the inflammatory response consequent to blood contacting artificial components of the CPB circuit have all been linked to postoperative NCD and to a lesser extent post-operative AF. The artificial components of the CPB circuit consist of stainless steel, polyvinylchloride (PVC), polycarbonate and other carbon-based plastics. In order to attenuate the negative sequelae of blood-circuit contact related inflammatory response, industry developed the biocompatible circuit (BCC) coating for the disposable CPB circuits. Four such coatings were studied and compared to an uncoated control group in a total of 101 patients undergoing routine CPB-assisted cardiac surgical procedures. Soluble adhesion molecule (SAM) activation was studied at different time points and common clinical outcomes such as white blood cell activation, serum renal function parameters urea and creatinine, postoperative bleeding, transfusion requirements, intensive care and hospital length of stay, CPB pump volume balances, changes in weight, postoperative serum lactate and glucose and the development of AF postoperatively, were compared. Additionally, postoperative neurocognitive testing was performed using a simple bedside neurocognitive test called the antisaccadic eye movement test. The patients in all groups were tested for comparison preoperatively and 72 hr postoperatively. Results: The mandate of BCC coating development and manufacture is to attenuate the well-documented and demonstrated inflammatory response consequent to the contact of blood with artificial CPB surfaces. The studied BCCs significantly decreased platelet transfusions in females. In addition, the BCCs decreased the concentrations of 2 SAMs when measured 6 hours after surgery and CPB. The difference in SAM expression seen between the coated and uncoated groups at 6 hr was no longer apparent at 72 hr. Very little difference was noted between the four BCC groups. Patients who developed AF postoperatively seemed predisposed to do so as the serum levels of soluble vascular cell adhesion molecule was significantly higher at baseline and remained so at 6 and 72 hr. The decreased platelet transfusions in females resulting from BCC use is a highly significant finding within this high-risk group of patients. As most platelet transfusions occur soon after the patient is disconnected from CPB, the short-term decrease in SAM activation can be linked to this improved clinical finding. The studied BCC coatings have achieved limited success in their intended mandate to attenuate inflammatory response in terms of improved clinical and laboratory desired outcomes.
127

Katheterablation von Vorhofflimmern

Piorkowski, Christopher 21 January 2011 (has links) (PDF)
Bedingt durch die zunehmende Prävalenz der Rhythmusstörung Vorhofflimmern mit den assoziierten Morbiditäts- und Mortalitätsrisiken ist die Entwicklung und Etablierung kurativer Therapieverfahren von klinischem und wissenschaftlichem Interesse. Entsprechend dem pathophysiologischen Verständnis der Arrhythmie-induzierenden Triggeraktivität und des Arrhythmie-erhaltenden Flimmersubstrat mit der vorrangigen anatomisch-strukturellen Lokalisation beider Entitäten im Übergangsbereich der großen Pulmonalvenentrichter in den posterioren linken Vorhof wurden katheterinterventionelle Ablationskonzepte als potentiell kurative Therapien entwickelt. Limitationen der praktischen Umsetzung theoretischer Linienkonzepte ergeben sich aus komplexen anatomischen Gegebenheiten und instabilen Zugangsbedingungen infolge Atmung und kardialer Mobilität. Aufbauend auf non-fluoroskopischen Navigationssystemen wurden Verfahren für vollständig Modell-integrierte Ansätze der Ablationslinienplatzierung entwickelt, bei denen Planung, Durchführung und Validierung der Ablation an anatomisch korrekten dreidimensionalen CT-Modellen des linken Vorhofes erfolgen. Zur Verbesserung instabiler Zugangsbedingungen wurden Verfahren der Katheternavigation mittels steuerbaren Schleusensystemen eingeführt und in entsprechenden Studien mit klinischen Endpunkten validiert. Zu objektivierbaren Erfassung von Energietransfer und myokardialer Läsionsbildung während der Ablation wurden katheterinterventionelle Kontakttechnologien, die auf der Messung lokaler komplexer Impedanzen zwischen Katheter und Gewebe beruhen, in der ersten klinischen Anwendung erprobt und validiert. Mit diesen technologischen Entwicklungen gelangen eine zunehmend akkuratere klinische Umsetzung theoretischer Ablationskonzepte und damit eine Etablierung des Therapiekonzeptes als klinisches Standardverfahren. Eine zur Abschätzung des Nutzen/Risiko-Profils nötige detaillierte Komplikationsanalyse stellte die Ösophagusverletzung als schwerste Komplikation heraus, die mit 0,3% selten auftrat, aber für nahezu alle langfristigen Folgeschäden verantwortlich war. Entwicklungen zur periprozeduralen Visualisierung des Ösophagus mit paralleler intraösophagealer Temperaturmessung sind Ansätze zur Vermeidung dieser Komplikation in der Zukunft. Bedingt durch das Auftreten und die postinterventionelle Zunahme asymptomatischer Flimmerrezidive ist die Frage eines objektiven Vorhofflimmermonitorings von entscheidender Bedeutung für die Beurteilung der Effektivität der Ablation sowie weitergehende klinische und wissenschaftliche Fragestellungen; wie die Indikation zur Antikoagulation oder den Vergleich von Rhythmus- und Frequenzkontrolle. 7-Tage-LzEKGs und transtelephonische EKGs wurden als Standard zum Monitoring innerhalb klinischer Vorhofflimmerstudien etabliert. Entwicklungen im Bereich implantierbarer kontinuierlicher Rhythmusmonitore werden in Zukunft das Netz zur Erfassung asymptomatischen Vorhofflimmerns weiter verdichten.
128

Does minimally invasive robotic surgical treatment alter exercise tolerance in patients with atrial fibrillation and mitral regurgitation at seven to eleven weeks post-operative?

Patel, Leena Jayesh. Gavin, Timothy P. January 2009 (has links)
Thesis (M.S.)--East Carolina University, 2009. / Presented to the faculty of the Department of Exercise and Sport Science. Advisor: Timothy P. Gavin. Title from PDF t.p. (viewed May 5, 2010). Includes bibliographical references.
129

Prieširdžių virpėjimo gydymas elektrine kardioversija ir veiksniai, sąlygojantys jos efektyvumą / Direct current cardioversion of atrial fibrillation and factors influencing its effectiveness

Stanaitienė, Giedrė 02 October 2008 (has links)
Prieširdžių virpėjimas (PV) dažniausiai klinikinėje praktikoje pasitaikanti širdies aritmija. PV dažnis populiacijoje – 0,4–1 proc. ir su amžiumi didėja, o tarp vyresnių nei 80 metų žmonių išauga iki 8 proc. Per pastaruosius 20 metų hospitalizavimo dėl PV atvejų padaugėjo 66 proc. PV metu išnyksta normali prieširdžių sistolė, vyksta prieširdžių remodeliavimasis, širdies ertmėse susidaro trombai, trinka hemodinamika. Tai susiję su sunkiomis komplikacijomis: širdies funkcijos nepakankamumu, insultu ir padidėjusiu mirštamumu. Veiksmingiausias PV nutraukimo būdas – elektrinė kardioversija, kuri klinikinėje praktikoje taikoma nuo 1962 m. Darbo tikslas – įvertinti prieširdžių virpėjimo gydymą elektrine kardioversija ir veiksnius, sąlygojančius jos efektyvumą. Darbo uždaviniai: 1. Nustatyti veiksnius, turinčius įtakos elektrinės kardioversijos efektyvumui. 2. Nustatyti ir įvertinti optimalią pradinio elektros impulso energiją, reikalingą prieširdžių virpėjimui nutraukti. 3. Nustatyti veiksnius, turinčius įtakos ankstyvajam prieširdžių virpėjimo atkryčiui po elektrinės kardioversijos. 4. Įvertinti veiksnius, nulemiančius elektrinės kardioversijos komplikacijas. Kauno medicinos universiteto Kardiologijos klinikos Kardiologijos intensyviosios terapijos skyriuje 2005–2007 m. atliktas prospektyvusis atsitiktinių imčių klinikinis tyrimas. Ištirta 224 prieširdžių virpėjimu sergančių pacientų, kuriems nuspręsta taikyti elektrinę kardioversiją sinusinio ritmo atkūrimui. Atsitiktinai... [toliau žr. visą tekstą] / Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. AF occurs in 0.4 – 1 % of population and its frequency increases with age and reaches 8 % above 80 years age. During the last 20 years hospitalization for AF rate increased by 66 %. In AF normal atrial systole does not occur, atrial remodeling starts, intracardiac thrombi start forming, haemodynamics becomes compromised. That leads serious complications – heart failure, stroke and increased mortality rate. The most effective AF termination method is direct current cardioversion, which has been used in clinical practice since 1962. The aim of the study was to evaluate the treatment of atrial fibrillation by direct current cardioversion and to identify the factors, contributing to its effectiveness. The objectives of the study: 1. To identify the factors, contributing to the effectiveness of direct current cardioversion. 2. To estimate and to evaluate the optimal energy of the initial electrical impulse required to terminate atrial fibrillation. 3. To identify the factors, contributing to immediate recurrence of atrial fibrillation after successful direct current cardioversion. 4. To evaluate the factors, influencing complications after direct current cardioversion. A prospective randomized clinical trial has been held in Intensive Care Unit of the Department of Cardiology of Kaunas Medical University Hospital between 2005 and 2007. We examined 224 patients with AF, selected for electrical... [to full text]
130

Einfluss des obrstruktiven Schlafapnoesyndroms auf den interventionellen Therapieerfolg bei Vorhofflimmern / Association between obstructive sleep apnea and long term success of pulmonary vein ablation using remote magnetic navigation

Hahnefeld, Lena Marie 25 February 2014 (has links)
No description available.

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