Dissertations / Theses on the topic 'Cardiovascular and autonomic response'
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Castaldo, Rossana. "Monitoring cardiovascular and autonomic response in real-life settings." Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/106454/.
Full textYoung, Tim. "Cardiovascular autonomic responses in pre- and post-ganglionic models of chronic autonomic failure." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/4718.
Full textMcginley, Jared Joseph. "Lateralized Induction of Cardiovascular Responses: Exploring Asymmetric Autonomic Regulation." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32888.
Full textMaster of Science
Calvo, González Mireia. "Analysis of the cardiovascular response to autonomic nervous system modulation in Brugada syndrome patients." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461612.
Full textEl síndrome de Brugada (SB) es una enfermedad genética asociada a un patrón electrocardiográfico característico y a un elevado riesgo de muerte súbita cardíaca (MSC), causada por fibrilación ventricular (FV) en ausencia de cardiopatías estructurales. Debido a su naturaleza compleja y multifactorial, la estratificación del riesgo supone, en la actualidad, uno de los aspectos más controvertidos. Ciertas alteraciones en la modulación del sistema nervioso autónomo (SNA) se han relacionado con eventos arrítmicos en esta población; no obstante, nuevos marcadores con valores predictivos más elevados que permitan identificar a aquellos pacientes con un alto riesgo de sufrir MSC son todavía necesarios. El uso de maniobras estandarizadas con el objetivo de estimular el SNA permiten mejorar la caracterización de la función autonómica. Por ello, en esta tesis doctoral se propone una evaluación exhaustiva de la respuesta cardiovascular a la modulación del SNA durante la noche, así como en respuesta al ejercicio y a la prueba de mesa inclinada, en una base de datos clínicos compuesta por sujetos con diferentes niveles de riesgo (pacientes sintomáticos y asintomáticos). En este contexto, la evaluación de la función autonómica se llevó a cabo mediante tres estrategias principales. En primer lugar, se caracterizaron y compararon la variabilidad y complejidad del ritmo cardíaco, así como la sensibilidad barorrefleja, en pacientes sintomáticos y asintomáticos, con el objetivo de identificar nuevos marcadores capaces de distinguir entre grupos de pacientes. Los resultados mostraron, en el grupo sintomático, una menor variabilidad y complejidad durante la noche, así como un mayor tono vagal y una menor actividad simpática tanto durante el ejercicio como en respuesta a la prueba de mesa inclinada. En un segundo análisis, se abordó la etiología multifactorial del síndrome mediante un enfoque multivariado basado en un método de aprendizaje automático por etapas. A partir de marcadores extraídos en la etapa anterior, se propusieron modelos predictivos capaces de clasificar pacientes diagnosticados con SB en función de su nivel de riesgo. El mejor clasificador (AUC = 95%) fue diseñado a partir de marcadores autonómicos obtenidos durante la noche, superando modelos predictivos previamente descritos para la estratificación del riesgo en el SB a partir de la combinación de parámetros no invasivos. Finalmente, se analizaron las interacciones entre las funciones mecánica, circulatoria y autonómica de estos pacientes a partir de modelos fisiológicos. En primer lugar, mediante la implementación y evaluación de un modelo computacional integrando la dinámica del sistema cardiovascular y su respuesta autonómica a la prueba de mesa inclinada. Asimismo, se propuso la identificación recursiva de un modelo implementado para el análisis de la evolución temporal de las contribuciones simpática y parasimpática del SNA durante una prueba de esfuerzo. Los resultados mostraron una menor contractilidad, así como una actividad parasimpática significativamente mayor durante el ejercicio, en pacientes sintomáticos. Con el objetivo de combinar características extraídas del modelado fisiológico, un último estudio prospectivo propuso el diseño de un clasificador multivariado integrando los parámetros estimados en esta última etapa. Los resultados obtenidos indican importantes tendencias de relevancia clínica que aportan nuevos conocimientos sobre los mecanismos autonómicos encargados de regular el sistema cardiovascular en el SB. Su interpretación permite mejorar la estratificación del riesgo en estos pacientes y, por tanto, optimizar las estrategias terapéuticas aplicadas. La metodología propuesta se presenta como un instrumento para la identificación de aquellos pacientes con alto riesgo de MSC que podrían beneficiarse de la implantación de desfibriladores automáticos.
Le syndrome de Brugada (BS) est une maladie cardiaque caractérisée par la survenue d’une syncope ou mort subite, provoquées par une arythmie cardiaque, chez les patients avec un coeur structurellement normal, mais présentant des altérations électrocardiographiques spécifiques. Cependant, ces modifications sont intermittentes et varient avec la température ou les traitements appliqués, ce qui rend particulièrement difficile le diagnostic chez un patient donné. En outre, elles sont fortement modulées par le système nerveux autonome (SNA), partie du système nerveux périphérique responsable de la régulation des organes internes. Les défibrillateurs implantables (DI) sont le traitement principal pour les patients symptomatiques, c’est-à-dire les patients documentés d’arythmie ventriculaire, syncope ou ayant survécu à un épisode de mort subite. Cependant, la décision d’implanter un DI peut être très difficile pour des patients asymptomatiques sans antécédents familiaux de morte subite. Dans ce contexte, l’objectif de la thèse était d’améliorer la compréhension de l’influence du SNA chez les patients souffrant du BS. Une méthodologie globale fusionnant traitement du signal, machine learning et modélisation a été proposée durant la thèse. Cette chaine de traitement originale a pu être mise en oeuvre sur trois bases de données de patients BS symptomatiques et asymptomatiques. Les bases de données cliniques utilisées dans ce travail sont le résultat d’une étude prospective, multicentrique dont l’objectif était de provoquer des modifications de l’activité du SNA chez les patients BS. L’acquisition des données s’est déroulée entre 2009 et 2013 dans le service de cardiologie du CHU de Rennes et les participants provenaient de 8 hôpitaux français situés à La Rochelle, Angers, Bordeaux, Brest, Nantes, Rennes, Poitiers et Tours. Afin de caractériser les patients présentant différents niveaux de risque, les participants ont été classés en patients symptomatiques et asymptomatiques, selon leurs historiques cliniques. Les patients symptomatiques devaient présenter les symptômes documentés suivants : arrêt cardiaque dû à une fibrillation ventriculaire, syncopes, vertiges, palpitations et convulsions nocturnes. La base de données est constituée des ECG (12 dérivations) de 87 patients, collectés pendant 24 heures, incluant un test d’orthostatisme (tilt-test) et une épreuve d’effort. L’acquisition était réalisée à l’aide d’un moniteur Holter (ELA medical, Sorin Group, Le Plessis Robinsson, France) à une fréquence d’échantillonnage de 1000 Hz. Par ailleurs, des tilt-tests ont été réalisés sur 32 patients en mesurant de manière non-invasive la pression artérielle et l’ECG avec le moniteur Task Force (CN Systems, Graz, Autriche) à une fréquence d’échantillonnage de 100 Hz et 1000 Hz, respectivement. Des signaux ECG à 12 dérivations échantillonnés à 1000 Hz ont été acquis chez 36 autres patients BS lors d’un test d’exercice avec le moniteur ECG (Cardionics, Webster, Texas). Par conséquent, l’analyse de l’activité du système nerveux autonome est basée sur 3 périodes différentes : 1) une épreuve d’effort, 2) un test d’orthostatisme (tilt-test) et 3) un recueil de données pendant la nuit. La réponse du système nerveux autonome, à ces trois tests, a tout d’abord été évaluée avec des méthodes d’estimation du gain du baroréflexe, de variabilité et de complexité cardiaque. L’une des difficultés du traitement des signaux associés à l’épreuve d’effort et au test d’orthostatisme réside dans leurs natures non-stationnaires. L’analyse spectrale de ces signaux nécessite la mise en oeuvre d’outils spécifiques permettant de décrire une évolution temporelle des caractéristiques fréquentielles. Des analyses temps-fréquence, basées sur la transformée de Wigner-Ville, ont ainsi été utilisées afin d’étudier conjointement, le contenu spectral des signaux, et leurs évolutions temporelles. Cependant, ces méthodes classiques d’analyse de la variabilité cardiaque ne permettent pas de capturer la non-linéarité de la dynamique cardiovasculaire. Ainsi, des méthodes spécifiques d’analyse de la complexité des séries cardiaques ont pu être utilisées. La sensibilité du baroréflexe de ces patients a été évaluée à partir de différentes méthodes proposées dans la littérature. Une série d’indices a ainsi été déduite des signaux avant d’être analysée pour trouver des différences significatives entre les patients symptomatiques et asymptomatiques. Les résultats ont mis en évidence que les indices calculés chez les patients symptomatiques sont associés à une baisse de la variabilité et de la complexité cardiaque pendant la nuit. Par ailleurs, pendant le test d’exercice, les patients symptomatiques ont montré une activité vagale augmentée et un tonus sympathique réduit. Lors de la réponse au tilt-test, les patients symptomatiques ont présenté une augmentation du tonus parasympathique et une réduction de l’équilibre sympatho-vagal par rapport aux patients asymptomatiques. L’étiologie multifactorielle du BS nécessite l’utilisation d’approches complexes capables de capturer les multiples mécanismes sous-jacents à la maladie. Ainsi, une analyse multivariée a été réalisée à partir de la série d’indices calculés précédemment. L’approche globale, basée sur des méthodes de machine learning, permet de combiner de manière optimale les indices autonomiques extraits précédemment, afin de concevoir des classificateurs capables de différencier les patients BS, en fonction de leur symptomatologie. La sélection de ces indicateurs autonomiques, permettant une meilleure caractérisation du BS, peut être difficile surtout lorsque le nombre de sources dépasse la quantité d’observations et que les variabilités entre patients sont significatives. Ainsi, une approche robuste basée sur un processus de sélection de paramètres en deux étapes a été mise en oeuvre. La méthodologie proposée a été optimisée, évaluée et comparée sur les données extraites lors de différents tests autonomiques. Les résultats montrent que le meilleur classificateur (AUC = 95%) a été conçu à partir de marqueurs autonomiques obtenus pendant la nuit, améliorant des modèles prédictifs décrits précédemment pour la stratification du risque dans le BS à partir de la combinaison de paramètres non invasifs. Bien que l’analyse multivariée proposée montre une amélioration des performances de classification par rapport à la littérature, les méthodes utilisées n’intègrent pas de connaissance physiologique dans le traitement des données. Or le BS étant une pathologie complexe et multifactorielle, l’utilisation de modèles mathématiques de connaissance peut s’avérer pertinente car cela permet l’intégration d’information physiologique dans le traitement des données et l’analyse de mécanismes sous-jacents qui sont difficiles ou impossibles à observer en clinique avec des méthodes non-invasives, comme le tonus vagal ou sympathique. Une analyse à base de modèle a été proposée durant la thèse afin : 1) d’étudier la réponse autonomique et hémodynamique au test d’orthostatisme chez des sujets sains et des patients BS, 2) de simuler les réponses vagales et sympathiques durant l’épreuve d’effort chez les patients BS symptomatiques et asymptomatiques. Concernant l’étude de la réponse au test d’orthostatisme, un modèle a été proposé de manière à intégrer les représentations : i) de l’activité électrique cardiaque, ii) de la mécanique des ventricules et des oreillettes, iii) des circulations systémique et pulmonaire et iv) du baroréflexe incluant les voies vagale et sympathique. Le modèle complet permet de simuler les réponses hémodynamiques et autonomiques au test d’orthostatisme. Des analyses de sensibilité, basées sur des méthodes globales et de criblage, ont mis en évidence l’importance de certains paramètres du baroréflexe et en lien avec la description des propriétés diastoliques des ventricules. Ces paramètres ont pu être identifiés, à l’aide d’algorithmes évolutionnaires, afin de créer des modèles spécifiques-patients de 8 sujets sains et 12 patients BS. Les résultats ont montré des différences significatives concernant la réponse sympathique au tilt-test entre sujets sains et BS. Par ailleurs, les patients symptomatiques et asymptomatiques sont associés des modifications significatives des paramètres diastoliques ventriculaires. Concernant les simulations de la réponse autonomique durant l’épreuve d’effort, un algorithme d’identification récursif a pu être mis en oeuvre sur un modèle composé des cavités cardiaques, des circulations systémique et pulmonaire, couplées au baroréflexe. L’identification récursive réalisée sur le modèle a permis une estimation des activités vagale et sympathique durant l’effort chez 13 patients BS symptomatiques et 31 asymptomatiques. Les patients symptomatiques ont montré une élévation significative de l’activité vagale, spécialement à la fin de l’échauffement. Les analyses réalisées sur les modèles proposés, concernant le test d’orthostatisme et l’épreuve d’effort, ont permis une exploration de variables physiologiques, difficilement observables. Les résultats obtenus avec les modèles mettent en évidence des modifications de la réponse hémodynamique cardiaque et confirment des modifications de la balance sympatho-vagale entre les patients symptomatiques et asymptomatiques. En résumé, les résultats obtenus mettent en évidence un déséquilibre de la balance sympathovagale entre les patients symptomatiques et asymptomatiques et montrent l’utilité des indices de variabilité cardiaque pour la classification des patients en fonction de la symptomatologie. Les résultats obtenus sont cohérents avec la littérature, rapportant un tonus vagal plus élevé, ainsi qu’une activité sympathique, variabilité et complexité cardiaques plus faibles, chez les patients symptomatiques. Des études précédentes ont rapporté que la plupart des événements cardiaques majeurs se produisent au repos et pendant le sommeil, ainsi que l’apparition des altérations électrocardiographiques caractéristiques du BS augmente avec la stimulation vagale. Les résultats obtenus pendant la nuit, lorsque l’activité parasympathique est prédominante, ont montré des résultats particulièrement pertinents pour la différentiation des populations de patients. De plus, étant donnée qu’il existe une activité parasympathique significativement plus élevée chez les patients symptomatiques pendant les tests d’exercice et d’orthostatisme par rapport aux sujets asymptomatiques, les résultats soulignent le rôle de l’analyse du tonus vagal pour la stratification du risque dans cette population. Enfin, l’analyse basée sur un modèle du système cardiovasculaire a permis de mettre en évidence des différences concernant les propriétés diastoliques cardiaques et la réponse du baroréflexe pendant le test d’orthostatisme. L’ensemble des résultats de la thèse permet une meilleure caractérisation des profils autonomiques des patients atteints du syndrome de Brugada et laisse envisager une amélioration de la sélection des patients pour implantation d’un DI.
Calvo, Gonźalez Mireia. "Analysis of the cardiovascular response to autonomic nervous system modulation in Brugada syndrome patients." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S056/document.
Full textBrugada syndrome (BS) is a genetic arrhythmogenic disease characterized by a distinctive electrocardiographic pattern, associated with a high risk for sudden cardiac death. Its complex and multifactorial nature turns risk stratification into a major challenge. Although variations in autonomic modulation are commonly related to arrhythmic events in this population, novel markers with higher predictive values are still needed so as to identify those patients at high risk. Since the autonomic function can be better characterized through the application of standardized maneuvers stimulating the autonomic nervous system (ANS), the main objective of this thesis is to evaluate and compare the cardiovascular response to ANS modulations overnight, as well as in response to exercise and HUT testing, on a series of BS patients with different levels of risk (symptomatic and asymptomatic subjects). In a first part of this work, we apply previously described methods for the analysis of heart rate complexity, baroreflex sensitivity, and non-stationary heart rate variability, never before studied in the context of BS patients. In a second part, in order to address the multifactorial nature of the disease, a multivariate approach based on a step-based machine learning method is introduced. By employing markers extracted at signal-processing analysis, robust classifiers capable of distinguishing patients at different levels of risk are proposed. The third part of this work has been focused on the proposal of novel mathematical models and the associated model analysis methods, so as to study the autonomic and hemodynamic responses to exercise and HUT testing. Finally, a prospective application of a multivariate approach integrating parameters extracted at the model-based stage is also presented. Overall, the obtained results provide new insights into the underlying autonomic mechanisms regulating the cardiovascular system in BS, improving physiopathology and prognosis interpretation. The proposed approach may be used as an instrument for the identification of those asymptomatic patients at high risk who may benefit from a cardioverter defibrillator implantation
El síndrome de Brugada (SB) es una enfermedad genética asociada a un patrón electrocardiográfico característico y a un elevado riesgo de muerte súbita cardíaca (MSC), causada por fibrilación ventricular (FV) en ausencia de cardiopatías estructurales. Debido a su naturaleza compleja y multifactorial, la estratificación del riesgo supone, en la actualidad, uno de los aspectos más controvertidos. Ciertas alteraciones en la modulación del sistema nervioso autónomo (SNA) se han relacionado con eventos arrítmicos en esta población; no obstante, nuevos marcadores con valores predictivos más elevados que permitan identificar a aquellos pacientes con un alto riesgo de sufrir MSC son todavía necesarios. El uso de maniobras estandarizadas con el objetivo de estimular el SNA permite una mejor caracterización de la función autonómica. El principal objetivo de esta tesis doctoral es, por tanto, la evaluación exhaustiva de la respuesta cardiovascular a la modulación del SNA en una serie de pacientes con SB y diferentes niveles de riesgo (sujetos sintomáticos y asintomáticos), a través de diferentes maniobras autonómicas, con la finalidad de identificar nuevos marcadores potencialmente útiles para la estratificación de riesgo en esta población. En este contexto, la evaluación de la función autonómica se llevó a cabo mediante tres estrategias principales. En primer lugar, se caracterizaron y compararon la variabilidad y complejidad del ritmo cardíaco, así como la sensibilidad barorrefleja, en pacientes sintomáticos y asintomáticos, con el objetivo de identificar nuevos marcadores capaces de distinguir entre grupos de pacientes. Los resultados mostraron, en el grupo sintomático, una menor variabilidad y complejidad durante la noche, así como un mayor tono vagal y una menor actividad simpática tanto durante el ejercicio como en respuesta a la prueba de mesa inclinada. En un segundo análisis, se abordó la etiología multifactorial del síndrome mediante un enfoque multivariado basado en un método de aprendizaje automático por etapas. A partir de marcadores extraídos en la etapa anterior, se propusieron modelos predictivos capaces de clasificar pacientes diagnosticados con SB en función de su nivel de riesgo. El mejor clasificador (AUC = 95%) fue diseñado a partir de marcadores autonómicos obtenidos durante la noche, superando modelos predictivos previamente descritos para la estratificación del riesgo en el SB a partir de la combinación de parámetros no invasivos. Finalmente, se analizaron las interacciones entre las funciones mecánica, circulatoria y autonómica de estos pacientes a partir de modelos fisiológicos. En primer lugar, mediante la implementación y evaluación de un modelo computacional integrando la dinámica del sistema cardiovascular y su respuesta autonómica a la prueba de mesa inclinada. Asimismo, se propuso la identificación recursiva de un modelo implementado para el análisis de la evolución temporal de las contribuciones simpática y parasimpática del SNA durante una prueba de esfuerzo. Los resultados mostraron una menor contractilidad, así como una actividad parasimpática significativamente mayor durante el ejercicio, en pacientes sintomáticos. Con el objetivo de combinar características extraídas del modelado fisiológico, un último estudio prospectivo propuso el diseño de un clasificador multivariado integrando los parámetros estimados en esta última etapa. Los resultados obtenidos indican importantes tendencias de relevancia clínica que aportan nuevos conocimientos sobre los mecanismos autonómicos encargados de regular el sistema cardiovascular en el SB. Su interpretación permite mejorar la estratificación del riesgo en estos pacientes y, por tanto, optimizar las estrategias terapéuticas aplicadas. La metodología propuesta se presenta como un instrumento para la identificación de aquellos pacientes con alto riesgo de MSC que podrían beneficiarse de la implantación de desfibriladores automáticos
Hautala, A. (Arto). "Effect of physical exercise on autonomic regulation of heart rate." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514273354.
Full textGiles, Luisa. "The cardiovascular, respiratory, systemic, and autonomic responses to exercise in diesel exhaust." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46012.
Full textUys, Aletta Sophia. "Comparing autonomic and cardiovascular responses in African and Caucasian men : the SABPA study / Aletta Sophia Uys." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9851.
Full textThesis (PhD (Physiology))--North-West University, Potchefstroom Campus, 2013.
Beda, Alessandro. "Cardiovascular and respiratory responses to psychophysiological tasks : methodological issues for assessing autonomic regulation." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440413.
Full textPark, Young Jin Medical Sciences Faculty of Medicine UNSW. "Effects of exercise-based lifestyle interventions on cardiovascular reactivity of untrained premenopausal women." Publisher:University of New South Wales. Medical Sciences, 2008. http://handle.unsw.edu.au/1959.4/41449.
Full textClaiborne, Stephen Alexander. "RESPONSE OF HEART RATE VARIABILITY TO PHYSIOLOGICAL STRESS IN HEALTHY COLLEGE STUDENTS." Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1524782664217834.
Full textBurgess, Kaleena Dennielle. "The Effect of Hostile and Benevolent Sexism on Women's Cardiovascular Reactivity to and Recovery from a Laboratory Stressor." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4646.
Full textTomimura, Suely. "Avaliação do estresse oxidativo e modulação autonômica cardiovascular pós-irradiação de laser de baixa intensidade em ratos espontaneamente hipertensos: estudo experimental." Universidade Nove de Julho, 2013. https://bibliotecatede.uninove.br/handle/tede/1132.
Full textMade available in DSpace on 2015-07-20T18:01:54Z (GMT). No. of bitstreams: 1 Suely Tomimura.pdf: 1781054 bytes, checksum: acaac7dbd088721fbe65530e5cd96c5f (MD5) Previous issue date: 2013-12-17
Due to the increasing numbers of Systemic Arterial Hypertension (HBP) patients in population and its senescence, steadily increased from 600 million in 1980 to 1.2 billion in 2008. The World Health Organization (WHO) in 2009 attributed to high blood pressure (BP) was the death cause for 9.5 million people worldwide. Currently, the hypertension has become a serious public health problem. This entity is an important risk factor for congestive heart failure, cerebrovascular disease, acute myocardial infarction, nephropathy, retinopathy and peripheral vascular insufficiency. Studies have suggested that laser photobiomulation, employing a low power, acts into the inflammatory and proliferative phases of tissue repair, by modulating the inflammatory mediators synthesis as same as the Reactive Oxygen Species (ROS). According scientific publications indicate that the inflammation component is closely related to systemic arterial hypertension as well as possibly to the oxidative stress, both participates in the Hypertension genesis. The aim of this study was to verify the long-term effects of Low Level Laser Therapy (LLLT) application in Spontaneously Hypertensive Rats-SHR (Spontaneously Hypertensive Rats) through on cardiovascular autonomic modulation and oxidative stress in the blood. The experiment consisted in 3 phases: Phase I – LLLT irradiation on SHR: The experiment's phase I consisted of animal’s irradiation, when the laser group received three times LLLT applications weekly for a 7 weeks total; the sham group received three times per week of LLLT simulation for 7 weeks and a total of 21 applications. Prospective, randomized, controlled study, with 16 SHR approximately 2 months age, randomly divided into 2 groups : Sham (n = 8) and Laser (n = 8). The animals were irradiated in a prompt, onto the tail’s dorsal area, using a Diode Laser (MMOptics, São Carlos, SP, Brazil) with a wavelength (λ) of 780 ± 2 (nm), output power at 40 mW, with a 0.04 cm2 beam area, dose of 30 J/cm2 power density of 1W/cm2 and irradiation time of 90 s. In Phase II - Hemodynamic and autonomic cardiovascular evaluation: for a period of 7 weeks, consisted in the cannulation procedure, collecting and analysis. The animals were cannulated, evaluated hemodynamically and analyzed the cardiovascular autonomic modulation. Phase III - Oxidative stress analysis, were analyzed: a) protein damage; b) cell membrane damage; c) antioxidant enzyme activity; d) nitrite concentrations. Data from phase II and III were collected and statistically analyzed applying One Way ANOVA test, followed by post hoc Student - Newman Keulls and considering the significance level of p < 0.05, equivalent to an error α 0.05. The results demonstraded hemodynamic parameters of group LLLT treated showed a BP reduction, when compared with the Sham group. In laser group the diastolic arterial pressure (DAP) showed a reduction of -14 mmHg (± 143 * 4 x 157 ± 3 mmHg Sham) and mean arterial pressure (MAP) - 13mmHg (169 ± 4 * x 182 ± 4 mmHg Sham) there were statistically significant difference. Although the value of systolic arterial pressure (SAP) (196 ± 5 x 207 ± 4 mmHg) showed no differences. There was a decreased in resting HR with a statistically significant difference in the laser group compared to Sham (312 ± 14 vs. 361 ± 13 bpm sham). The spectral reviews in the field of time and frequency showed that the Laser group decreased sympathetic activity on the heart and blood vessels while compared to the Sham group. The heart rate variation was analyzed using the DP-PI ( standard deviation of the pulse interval) VAR-PI components (pulse interval variability) and it demonstrated that LLLT was effective in diminishing variation in heart rate (HR) and sympathetic activity in heart, inducing a substantial fall in blood pressure. Lasertherapy presented a rise in spectral low-frequency component in the pulse interval (LF - IP action of the sympathetic at heart), though the sham group showed up exaggeratedly decreasing (6.77 ± 4:35 and 2:31 ± 0:16 ms ² Sham) as a function of saturation variation. Thus, there was a significant reduction in sympathetic activity after LLLT using. A high-frequency band on interval pulse HF-IP (parasympathetic activity) showed no statistically significant differences between the groups and Laser Sham group. The baroreceptor sensitivity, assessed by the alpha index, signalized a significant increase in the Laser (1:07 ± 0:23 vs. 0:45 ± 0:20 ms / mmHg Sham) group, presenting an improvement in the receptors sensitivity. The baroreflex results were associated with other relevant data, the VAR - SAP (49.55 ± 15.94 * vs 70.51 ± 13:55 mmHg² Sham) and SD -SAP (6.94 ± 1.21 * vs 8.68 ± 1.11 mmHg Sham) that proved to be diminished in the laser group, indicating baroreflex improvement sensitivity concomitantly to the positive SAP variation reduction of. There were no significant differences in baseline SAP (196 ± 5 vs. 207 ± 4 mmHg Sham) between the two groups. The results in the oxidative stress and autonomic analysis demonstrated an association between increased NO production (nitrite 0:36 ± 0:03 vs 0:26 ± 0:03 nm / mg Sham) and decreased in the vascular sympathetic (LF - SAP 7.28 ± 1.63 * vs 9.86 ± 0.47 Sham), both leading to a profound vasodilatation then a significant fall in of blood pressure. Lasertherapy shown to alter the plasma parameters such as oxidative nitrite, revealing an NO increased metabolism, as described above and, moreover, accounted for a significant reduction in carbonyl plasma concentration (vs 3.93 ± 0.24, 4.75 ± 0:26 * nm / mg Sham). Our experimental study indicate that LLLT was able to reduce the oxidative stress parameters through diminishing the damage to the proteins. The enzymatic defense was analyzed by the enzyme SOD concentration in blood plasma, denoted that no significant differences (4:42 ± 0:10 4:25 ± 0:06 vs usod / mg) between groups. Thus, low level laser therapy has shown to improve cardiovascular autonomic activity as well as oxidative parameters which resulted in steadily staggeringly reduce the blood pressure of hypertensive animals.
Em razão do aumento populacional e a senescência, o número de indivíduos com Hipertensão Arterial Sistêmica (HAS) cresceu de 600 milhões em 1980 para 1,2 bilhões (OMS 2011). Lim (2012) atribuiu que a pressão arterial (PA) elevada fosse a causa mortis de 9,5 milhões de indivíduos ao redor do mundo. Atualmente, a HAS tornou-se um grave problema de saúde pública. A hipertensão é um importante fator de risco para insuficiência cardíaca congestiva, doenças cerebrovasculares, infarto agudo do miocárdio, nefropatia, insuficiência vascular periférica e retinopatia hipertensiva. Considerando publicações científicas que demonstram que o componente da inflamação e do estresse oxidativo estão intimamente relacionados à gênese da hipertensão arterial sistêmica (HAS), e que o laser com potência baixa tem efeito positivo no estresse oxidativo e apresenta ação antiinflamatória eficaz, desta forma buscamos estudar a resposta da Laserterapia na HAS. Inúmeros estudos vêm sugerindo, ao longo de décadas, que a fotobiomulação pelo laser empregado uma potência baixa, atua durante as fases inflamatórias e proliferativas da reparação tissular, modulando síntese de mediadores inflamatórios e espécies reativas de oxigênio (ROS). O objetivo deste estudo foi analisar os efeitos da aplicação do laser de baixa intensidade em ratos espontaneamente hipertensos SHR (Spontaneously Hypertensive Rats) em longo prazo na modulação autonômica cardiovascular e no estresse oxidativo sangúineo. Estudo prospectivo, randomizado e controlado com 16 ratos SHR, divididos aleatoriamente em 2 grupos: Sham (n=8) e Laser (n=8).O experimento foi dividido em três fases: Fase I – Irradiação dos animais: constituiu-se na irradiação com laser nos animais SHR, onde o grupo Laser recebeu três aplicações semanais de LBI durante sete semanas; já no grupo Sham foram realizados três simulações de aplicação semanais de Laser de Baixa Intensidade (LBI) durante 7 semanas, totalizando 21 aplicações de LBI. Os animais foram irradiados pontualmente, na região dorsal da cauda, utilizando um Laser Diodo (MMOptics, São Carlos, SP, Brasil) com comprimento de onda de λ = 780 ± 2 (nm); potência de 40 mW, área do feixe de 0,04 cm2, densidade de energia de 30 J/cm2, densidade de potência de 1W/cm2, tempo total de irradiação de 90 s de exposição. Fase II – Avaliação hemodinâmica e autonômica cardiovascular: constituiu-se nos procedimento de canulação, registro de dados e coleta de material, teve inicio após sete semanas de irradiação. Os animais canulados foram avalidados de forma hemodinâmica, bem como analisada a modulação autonômica cardiovascular. Fase III – Análises do estresse oxidativo, foram analisadas: a) danos à proteína; b) danos à membrana celular; c) atividade enzimática; d) concentração de nitrito. Os dados da fase II e III foram coletados e analisados estatisticamente através dos testes Anova One Way, seguido de Post Hoc de Student Newman-Keulls, considerando-se o nível de significância p < 0,05, equivalendo a um erro α de 0.05. Os resultados hemodinâmicos do grupo tratado com LLLT denotaram um decréscimo significativo da PA quando comparado com o grupo Sham. A pressão arterial diastólica (PAD) do grupo Laser revelou uma redução de -14 mmHg (143± 4*vs157±3 mmHg Sham) e a pressão arterial média (PAM) -13mmHg (169±4*vs182±4 mmHg Sham), a frequência cardíaca (FC) em repouso (312±14*vs361±13 bpm Sham) revelando uma diferença estatisticamente significante, porém o valor da pressão arterial sistólica(PAS) não mostrou (196±5 x 207±4 mmHg) alterações entre os grupos. As avaliações espectrais no domínio do tempo e da frequencia demostraram que o grupo Laser reduziu a atividade simpática sobre o coração e vasos sanguíneos quando comparados ao grupo Sham. A variação frequência cardíaca foi analisada através dos componentes VAR-IP (variabilidade do intervalo de pulso) e o DP-IP (desvio do intervalo de pulso) que evidenciaram que o LBI foi eficaz no decréscimo variação da FC e da atividade simpática no coração, induzindo assim a queda das pressões arteriais. A laserterapia mostrou um incremento no componente espectral baixa frequência no intervalo de pulso (BF-IP ação do simpático no coração), porém o grupo Sham apresentou-se exacerbadamente diminuído (6.77 ± 4.35 e 2.31±0.16 ms² Sham) em função da saturação da variação desse componente que foi reduzido. Desta forma, houve um importante decréscimo da atividade simpática com o uso do LBI, significando uma importante diminuição dos níveis pressóricos. A banda de alta frequência (AF-IP atividade parassimpática cardíaca) não mostrou diferenças estatísticas significantes entre os grupos Laser e grupo Sham. A sensibilidade dos barorreceptores, avaliada pelo índice alfa, demonstrou um significativo incremento da resposta no grupo Laser (1.07 ± 0.23 vs 0.45 ± 0.20 ms/mmHg Sham), revelando uma melhora na sensibilidade destes receptores. Os resultados dos barorreflexos encontravam-se associados a outro dado relevante, o componente VAR-PAS (49.55 ± 15.94* vs 70.51 ± 13.55 mmHg² Sham) e DP-PAS (6.94 ± 1.21* vs 8.68 ± 1.11 mmHg Sham) que mostrou-se diminuído no grupo Laser, indicando que a melhora da sensibilidade barorreflexa ocorreu, concomitantemente, à redução positiva da variação da PAS. Não houve diferenças estatísticas significantes na PAS basal (196±5 vs 207 ± 4 mmHg Sham) entre os dois grupos. Já os resultados encontrados na análise do estresse oxidativo e autonômica demonstraram uma associação entre o incremento da produção do óxido nitrico (NO) (nitrito 0.36 ± 0.03 vs 0.26 ± 0.03 nm/mg Sham) e redução do simpático vascular (BF-PAS 7.28 ± 1.63* vs 9.86 ± 0.47 Sham), ambos levando a uma vasodilatação com consequente queda dos níveis pressóricos arteriais. A laserterapia mostrou alterar parâmetros oxidativos como as espécies reativas de nitrogênio (RNS reactive nitrogen species), o nitrito plasmático, revelando um aumento do metabolismo do NO, como já descrito anteriormente e denotou uma diminuição significativa da concentração de carbonilas plasmáticas (3.93 ± 0.24 * vs 4.75 ± 0.26 nm/mg Sham). A defesa enzimática foi analisada através da concentração da enzima SOD no plasma sanguíneo, que não apontou diferenças significativas (4.42 ± 0.10 vs 4.25 ± 0.06 usod/mg) entre os grupos. Evidenciamos que o LBI foi capaz de reduzir este parâmetro oxidativo, reduzindo os danos às proteínas decorrente do estresse. Desta forma, concluímos que a laserterapia demonstrou resposta positiva ao melhorar a atividade autonômica cardiovascular e parâmetros oxidativos que resultaram na redução dos níveis pressóricos dos animais hipertensos.
Kallio, M. (Mika). "Cardiovascular autonomic dysfunction in Parkinsonian syndromes." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514264487.
Full textYlitalo, A. (Antti). "Cardiovascular autonomic regulation in systemic hypertension." Doctoral thesis, Oulun yliopisto, 1999. http://urn.fi/urn:isbn:9514252128.
Full textRitter, Ophelie. "Effets périphériques et centraux de l'exercice excentrique aigu sur bicyclette ergométrique chez le sujet sain et le patient atteint de BPCO." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD024.
Full textNew exercise modalities are required for patients severely limited during exercise such as chronic obstructive pulmonary disease patients (COPD). Eccentric “cycling”, characterized by better efficiency, could allow COPD patients to train more effectively. Nonetheless, prescription modalities and effects of eccentric cycling deserve to be more studied.In healthy subjects, our results showed a delayed parasympathetic reactivation after eccentric compared to concentric cycling matched for mechanical power, together with an influence of pedalling frequency on autonomic and cardiorespiratory responses. At similar metabolic power, eccentric cycling is characterized by a greater cardiovascular and respiratory stress than during concentric cycling, and altered autonomic nervous systems responses in favour to greater sympathetic activity. Vascular function is altered after eccentric cycling. In COPD patients, as in healthy subjects, eccentric cycling impose tachypneic breathing pattern.We believe that the higher muscle tension during eccentric cycling necessary to reach metabolic power similar to concentric leads to greater sympathetic activity and peripheral hemodynamic constraint, likely explaining the increased constraints on cardiovascular system during eccentric cycling
Wang, Siqi. "NONINVASIVE ASSESSMENT AND MODELING OF DIABETIC CARDIOVASCULAR AUTONOMIC NEUROPATHY." UKnowledge, 2012. http://uknowledge.uky.edu/cbme_etds/5.
Full textMiranda, Luísa Maria da Cruz Soares. ""Associations between cardiovascular risk factors, physical activity and autonomic function"." Tese, Faculdade de Desporto da Universidade do Porto, 2011. http://hdl.handle.net/10216/56801.
Full textMiranda, Luísa Maria da Cruz Soares. ""Associations between cardiovascular risk factors, physical activity and autonomic function"." Doctoral thesis, Faculdade de Desporto da Universidade do Porto, 2011. http://hdl.handle.net/10216/56801.
Full textSteele, Shelby L. "Autonomic Control of Cardiac Function." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19763.
Full textHooper, Justin Shane. "Cardiovascular Effects Evoked by Airway Nociceptive Reflexes in Healthy and Cardiovascular Diseased Rats." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6258.
Full textNelson, Jasmine N. Fadel Paul J. "Metabolic and autonomic nervous system effects of bariatric surgery." Diss., Columbia, Mo. : University of Missouri-Columbia, 2009. http://hdl.handle.net/10355/6658.
Full textLamensdorf, Angela Mona-Lisa. "Cardiovascular risk and autonomic changes during high and low affect provocations." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28098.
Full textArts, Faculty of
Psychology, Department of
Graduate
Esco, Michael R. Blessing Daniel L. "Cardiovascular autonomic modulation following maximal exercise Its relationship to race, VO2max, and resting heart rate variability /." Auburn, Ala, 2009. http://hdl.handle.net/10415/1626.
Full textOnyemaechi, Clinton. "Autonomic Nerve Activity and Cardiovascular Function in the Chicken Embryo [Gallus gallus]." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc1404516/.
Full textO'Driscoll, Jamie. "Differences in autonomic function between high and low cardiovascular disease risk patients." Thesis, University of West London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527469.
Full textMukkamala, Ramakrishna 1971. "Closed-loop system identification of cardiovascular control mechanisms in diabetic autonomic neuropathy." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36969.
Full textIncludes bibliographical references (p. 92-95).
by Ramadrishna Mukkamala.
M.S.
Onyemaechi, Clinton. "Autonomic Nerve Activity and Cardiovascular Function in the Chicken Embryo (Gallus gallus)." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404516/.
Full textKaemingk, Kristine Lynn. "Human immunodeficiency virus and the autonomic nervous system: A study of cardiovascular reflexes." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277035.
Full textD'Silva, Lindsay Antonio. "Longitudinal characterisation of cardiovascular haemodynamic and autonomic nervous system function in normal pregnancy." Thesis, Swansea University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678627.
Full textMäkikallio, A. (Anne). "Cardiovascular autonomic and hormonal dysregulation in ischemic stroke with an emphasis on survival." Doctoral thesis, University of Oulu, 2005. http://urn.fi/urn:isbn:9514278526.
Full textNelligan, Julie. "Anxiety and autonomic nervous system function during stress and recovery." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1060797984.
Full textTitle from first page of PDF file. Document formatted into pages; contains xiii, 127 p.; also includes graphics Includes bibliographical references (p. 91-105). Available online via OhioLINK's ETD Center
Jones, Emma Louise. "Assessment of the autonomic nervous system through the study of cardiovascular autonomic reflexes and their association with inflammation in three clinical settings." Thesis, Bournemouth University, 2014. http://eprints.bournemouth.ac.uk/21493/.
Full textLaird, Angela S. Medical Sciences Faculty of Medicine UNSW. "Autonomic dysreflexia following high level spinal cord injury: time course, mechanisms and possible intervention." Awarded by:University of New South Wales. School of Medical Sciences, 2007. http://handle.unsw.edu.au/1959.4/31523.
Full textClift, Paul F. J. "Endothelin and the cardiovascular response to hypoxia." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341139.
Full textKalla, Manish. "Mechanistic insights in the autonomic modulation of ventricular arrhythmia." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:019a87c7-322d-4d0b-befa-0da43378b13f.
Full textEverhart, Daniel Erik Jr. "Cerebral Regulation of Cardiovascular Functioning and Fluency among Anxious and Nonanxious Men." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30497.
Full textPh. D.
Vella, Elizabeth Jane. "The Autonomic Characteristics of Defensive Hostility: Reactivity and Recovery to Active and Passive Stressors." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33754.
Full textMaster of Science
Knepp, Michael Matthew. "Cardiovascular Reactivity to and Recovery from Laboratory Tasks in Low and High Worry Women." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/37508.
Full textPh. D.
Nelson, Charles. "Autonomic Balance and Control of Stress for Participants Identified as High or Low Hostile and as Having a Positive or No Family History of Cardiovascular Disease." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4301/.
Full textSpitler, Kevin M. "The Role of the Monkey Amygdala in the Autonomic Expression of Emotion." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194823.
Full textLabruto, Fausto. "Modifications of cardiovascular response to ischemia and trauma /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-379-5/.
Full textZamanian, Sam Ahmad. "Modeling and simulating human cardiovascular response to acceleration." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40536.
Full textIncludes bibliographical references (p. 95-98).
The human cardiovascular system routinely encounters conditions that cause it to adapt. For example, when an astronaut enters microgravity, his/her cardiovascular system adapts rapidly to the weightless environment with no functional impairment. This adaptation is entirely appropriate while in space. However, it predisposes astronauts to problems when they return. It has been suggested that the regimen for astronauts on long-duration space travel include periods of artificial acceleration via centrifugation, in order to maintain some exposure to a gravitational gradient and thus ameliorate some of the physiological consequences of exposure to microgravity. To design such an intervention, it is desirable to know and understand, as well as to predict the cardiovascular response to centrifugation stress. A reasonably compartmentalized mathematical model of the cardiovascular system that represents these conditions is presented, which will allow for understanding and predicting cardiovascular behavior under such conditions. We validated our simulations against human data and showed that our results closely matched the experimental data. Upon validation, we used our model to predict the response of the cardiovascular system to levels of stress that cannot yet be tested on human subjects.
by Sam Ahmad Zamanian.
S.M.
Heldt, Thomas 1972. "Computational models of cardiovascular response to orthostatic stress." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28761.
Full textIncludes bibliographical references (p. 163-185).
The cardiovascular response to changes in posture has been the focus of numerous investigations in the past. Yet despite considerable, targeted experimental effort, the mechanisms underlying orthostatic intolerance (OI) following spaceflight remain elusive. The number of hypotheses still under consideration and the lack of a single unifying theory of the pathophysiology of spaceflight-induced OI testify to the difficulty of the problem. In this investigation, we developed and validated a comprehensives lumped-parameter model of the cardiovascular system and its short-term homeostatic control mechanisms with the particular aim of simulating the short-term, transient hemodynamic response to gravitational stress. Our effort to combine model building with model analysis led us to conduct extensive sensitivity analyses and investigate inverse modeling methods to estimate physiological parameters from transient hemodynamic data. Based on current hypotheses, we simulated the system-level hemodynamic effects of changes in parameters that have been implicated in the orthostatic intolerance phenomenon. Our simulations indicate that changes in total blood volume have the biggest detrimental impact on blood pressure homeostasis in the head-up posture. If the baseline volume status is borderline hypovolemic, changes in other parameters can significantly impact the cardiovascular system's ability to maintain mean arterial pressure constant. In particular, any deleterious changes in the venous tone feedback impairs blood pressure homeostasis significantly. This result has important implications as it suggests that al-adrenergic agonists might help alleviate the orthostatic syndrome seen post-spaceflight.
by Thomas Heldt.
Ph.D.
Mickelson, Carol Smith. "Do aggressive video games cause increased cardiovascular response?" Scholarly Commons, 1997. https://scholarlycommons.pacific.edu/uop_etds/2317.
Full textAnsakorpi, H. (Hanna). "Cardiovascular regulation in epilepsy with emphasis on the interictal state." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514271343.
Full textScanlin, Matthew C. "The Effects of a Hydration Intervention on Cardiac Function, Autonomic Activity, and Cerebral Oxygenation during Phlebotomy." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1428598371.
Full textTurkstra, Lyn Siobhan. "Autonomic response to auditory and visual stimulation in severely brain-injured adults." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186485.
Full textPardikes, Thomas James. "Measuring the Relationship Between Reflexive and Intentional ANS Response." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32518.
Full textMaster of Science
Grant, Shara Soyini. "Multidimensional Cardioception and Trait Anxiety: Potential Clues from Baroreflex Sensitivity." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/96657.
Full textPHD