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1
Soueidan, Karen. "Augmented blood pressure measurement through the estimation of physiological blood pressure variability." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28828.
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Current noninvasive blood pressure (BP) measurement methods estimate the systolic and diastolic blood pressure (SBP and DBP) at two random instants in time. The BP variability and its serious consequences on the measurement are not recognized by most physicians. The standard for automated BP devices sets a maximum allowable system error of +/- 5 mmHg, even though natural BP variability often exceeds these limits. This thesis characterizes the variability of SBP and DBP and proposes a new approach to augment the conventional noninvasive measurement using simultaneous recordings of the oscillometric and continuous arterial pulse waveforms by providing: 1) The mean SBP (or DBP) over the measurement interval, 2) Their respective standard deviations, and 3) An indicator as to whether or not the oscillometric reading is an outlier. Recordings with healthy subjects showed that the approach has prominent potential and does not suffer from bias relative to the conventional method.
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Svensson, Per. "Blood pressure, blood pressure variability and myocardial ischemia : studies in patients with peripheral arterial disease and matched control subjects /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-826-2.
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Dawson, Suzanne L. "Blood pressure variability and cerebral autoregulation in acute ischaemic stroke." Thesis, University of Leicester, 2000. http://hdl.handle.net/2381/29609.
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This thesis examines the haemodynamic changes that occur following acute ischaemic stroke with reference to beat-to-beat blood pressure (BP) levels and variability as well as static and dynamic cerebral autoregulation (CA). Elevated 24h BP levels following acute stroke are associated with a poor outcome, but whether shorter durations of recording using beat-to-beat measurements or other BP parameters such as variability have the same prognostic significance is unknown. A single 10 minute non-invasive beat-to-beat BP monitoring period following acute cerebral infarction showed that increasing BP levels and beat-to-beat beat variability of mean arterial and diastolic BP were associated with a worse prognosis in terms of post ictal death/disability. These initial prognostic findings for BP variability might be explained if CA responses to rapid changes in systemic BP were impaired post stroke. The second part of the thesis set out to measure dynamic and static CA using novel non-invasive techniques employing transcranial Doppler ultrasonography to measure cerebral blood flow velocity in response to non-pharmacologically induced pressor and depressor BP stimuli. The initial study found that in normal controls, the reproducibility and actual values obtained for the autoregulatory indices for both static and dynamic tests varied according to the BP stimulus used. As a result of these initial studies thigh cuff release was used as the stimulus for dynamic CA, and isometric hand grip and thigh cuff inflation as the stimuli for static CA. When the CA results for a study group of acute ischaemic stroke patients were compared to an age and sex matched control group dynamic CA was significantly reduced in the patients' affected and non-affected hemispheres, whereas static CA was unimpaired.
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Terathongkum, Sangthong. "Relationships Among Stress, Blood Pressure, and Heart Rate Variability in Meditators." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/1497.
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PROBLEM STATEMENT: Growing evidence indicates that psychological stress contributes to cardiovascular diseases through complex neuroendocrine mechanisms. Psychological stress leads to several physiological responses including increased heart rate (HR) and blood pressure (BP) as well as decreased heart rate variability (HRV) through alterations in the autonomic nervous system (ANS), specifically increased sympathetic nervous system (SNS) activity and decreased parasympathetic nervous system (PNS) activity. Meditation is thought to induce an innate relaxation response leading to reduced psychological stress. Findings from past studies have provided inconclusive evidence regarding the direction and strength of relationships among stress, BP, HRV, and meditation practice. PROCEDURES: A cross-sectional descriptive-correlational design was used to examine relationships among perceived stress, BP, HRV and meditation practice in meditators. A convenience sample of 71 meditators at two meditation centers in the southeast United States was used. Sample size was based on a power analysis. Each participant was asked to complete meditation, perceived stress, and demographic questionnaires. Participants' BP was measured before meditation and HRV was recorded during a 30 minute meditation session. Finally, BP was recorded after meditation. RESULTS: Participants were predominantly female (55%), Caucasian/white (94%), and Buddhist (76%), with 93% having at least college graduate. Most participants practiced soto zen or vipassana meditation (45% and 30%, respectively). The average length of total meditation practice was 103.66 months. Participants practiced meditation an average of once a day for 4 days a week with mean session duration of 34 minutes. Most participants had a low level of perceived stress and normal HRV. There was a statistically significant decrease in mean systolic BP after meditation (t = 5.31, p CONCLUSIONS: The results suggested meditators had low levels of perceived stress and that meditation had an effect on systolic BP and perceived current stress. Future research needs to include longitudinal studies to elucidate the cumulative effects of consistent meditation practice on psychological and physiological outcomes.
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Rantala, M. (Maire). "Dietary modification and genetic variability of atherosclerosis risk factors." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514256522.
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Abstract
The risk factors for atherosclerosis and coronary heart disease
(CHD) are multiple and may interact with each other. Diet has a
significant role among the main risk factors for atherosclerosis,
as it regulates the levels of plasma lipids and lipoproteins, their
oxidative modification or protection from oxidation, blood pressure,
energy balance, and thrombogenesis. Nutrients can transfer their
effects directly through plasma concentrations or modify the cell
transduction or gene expression of important regulatory genes. The
response to dietary modification varies between individuals. The plasma
cholesterol response induced by dietary modification is at least
partly regulated genetically and some of the variation is explained
by other environmental factors.
Apolipoprotein E (apo E) and apolipoprotein B (apo B) are
the key regulatory proteins in cholesterol and lipoprotein metabolism.
The genetic variation of apo E is associated with the plasma lipid
levels and the CHD risk. The polymorphic variation of the apo B
gene is also associated with increased plasma cholesterol and CHD
risk. Obesity is associated with increased morbidity and mortality.
Plasma lipid abnormalities, impaired glucose metabolism and increased
blood pressure caused by obesity are the main reasons for increased
CHD mortality among obese subjects.
To study the magnitude of the response to dietary modification,
genetically selected groups were investigated. Dietary modification
had a significant impact on plasma total, LDL, and HDL cholesterol
concentrations, and the individual response in plasma LDL cholesterol
varied from 3 to 100%. The role of genetic variation in
the apo E gene was not significant in the lipid response, but the
blood pressure response was more distinct among subjects with the ε 4
allele than those with the ε 3 allele. The determination
of apo B EcoRI and MspI gene polymorphisms revealed subjects with a
greater response to diet, a finding which may have clinical importance
in the future for the attempt to identify subjects for effective
dietary counselling.
The effect of caloric restriction on gene expression was studied
in obese gallstone patients. Moderate weight reduction during caloric
restriction was associated with reduced lipoprotein lipase gene
expression, while the cholesteryl ester transfer protein gene expression
remained unchanged. Some of the beneficial changes in plasma lipids
and lipoproteins during and after weight reduction may be followed
by altered transcription of their modifying genes.
Meta-analysis is a modern and generally accepted method. Many
clinical uncertainties can be solved by combining all the data available
to a quantitative and objective analysis. However, the use of meta-analysis
do not resolve the problem of the effect of publication bias.
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Manning, Lisa Suzanne. "Blood pressure variability : its definition, measurement, and prognostic significance in acute stroke." Thesis, University of Leicester, 2016. http://hdl.handle.net/2381/37832.
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Background: How best to manage elevated blood pressure (BP) in the acute stroke period remains unclear. Blood pressure variability (BPV), that is variability in BP over a period of time, may predict outcome in acute stroke, and could explain the ongoing uncertainty surrounding acute stroke BP management. Moreover, it presents a potentially modifiable therapeutic target. Evidence of the effect of BPV on outcome following stroke is scarce, and how best to measure or define BPV in acute stroke is unknown. Objectives: This thesis aimed to determine the prognostic significance of BPV in acute stroke, and to investigate how best to measure and define BPV in the immediate post-stroke period. Methods: The following studies were undertaken: a systematic review and meta‐analysis of observational studies to assess the effect of BPV on outcome in acute stroke; a feasibility study to assess the ability of a novel BP measurement device to capture very‐short‐term BPV; post‐hoc analyses of three acute stroke randomised controlled trials to assess the effect of BPV on outcome using individual patient data; a prospective observational study to measure acute stroke BPV using a variety of measurement techniques. Results: This thesis has demonstrated that greater BPV is associated with poor outcome in acute stroke. However, the presence and strength of this relationship is influenced by a number of factors including: frequency, timing, and nature of BP measurements; time from stroke onset; BPV parameters; use of thrombolytic therapy; and the timing of outcome measures. For the first time in acute stroke, the observational study describes and compares beat‐to‐beat, casual cuff, and ambulatory BP monitoring (ABPM) derived BPV, showing that it is feasible and acceptable to patients to measure BPV using casual cuff and beat‐to‐beat measurements, and reports significant associations between beat‐to‐beat and casual cuff BPV parameters and outcome.
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Seydnejad, Saeid Reza. "Analysis of heart rate variability and blood pressure variation by nonlinear modelling techniques." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7814.
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Schurtz-Bouissou, Camille. "Relations entre la variabilité tensionnelle et la rigidité des gros troncs artériels chez le rat : Etudes dans trois modèles expérimentaux." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST0070.
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La rigidité artérielle ayant une valeur prédictive forte et indépendante d'évènements cardiovasculaires, nous émettons l'hypothèse que l'accumulation de variations de contraintes hémodynamiques altère la fonction et la structure des gros troncs artériels, indépendamment du niveau de pression artérielle. Nous avons donc mesuré l'impact de la variabilité tensionnelle sur la rigidité et la structure artérielles dans différents modèles de variabilité tensionnelle chez le rat.Chez le rat barodénervé et le rat sympathectomisé par la guanéthidine, 2 modèles de variabilité tensionnelle à court terme, une augmentation de la rigidité artérielle est associée à des altérations tissulaires différentes. En effet chez les rats barodénervés, une hypertrophie aortique est couplée à une augmentation du collagène et des attachements cellule-matrice (fibronectine et intégrine α5). Au contraire, chez les rats sympathectomisés, une hypotrophie vasculaire est associée à une diminution de l'élastine et une augmentation des attachements via l'intégrine αv.Nous avons ensuite créé, caractérisé et validé un modèle de variabilité tensionnelle à long terme, le rat spontanément hypertendu traité de façon discontinue par un antihypertenseur. Le traitement discontinu réduit la pression artérielle systolique tout en augmentant isolément la variabilité tensionnelle à long terme. La rigidité artérielle, élevée sous traitement discontinu, est associée à une hypertrophie vasculaire avec augmentation des attachements (fibronectine et intégrine αv) et sans modification du rapport élastine/collagène.En conclusion, l'élevation de variabilité tensionnelle engendre de la rigidité artérielle, et ce à pression artérielle constante. Les altérations structurales dans les modèles de variabilité tensionnelle étudiés impliquent des mécanismes différents reposant sur des modifications des relations cellule-matrice, mettant en jeu la fibronectine et les intégrines α5 et αvArterial stiffness is nowadays accepted as a strong and independent predictor of cardiovascular disease. We hypothesized that increased blood pressure variability (BPV) may lead to arterial damage, independently of the blood pressure level. We thus aimed investigating the relationship between BPV and arterial stiffness and composition of the aorta in different rat models of increased BPV.In a first study performed in two models of increased short term BPV, sinoaortic denervated and chemically sympathectomized rats, an increase in wall stiffness was associated with different modifications of cell-extracellular matrix adhesion. Indeed in sinoaortic denervated rats, increased media cross-sectional area was coupled with an increased collagen content and muscle cell attachments to its cell-extracellular matrix (fibronectin and its α5β1 integrin). In contrast, chemically sympathectomized rats were characterized by a reduced media cross-sectional area associated to a reduction of elastin content and upregulation of αvβ3 integrin.In a second study, we created, characterized and validated a new experimental model of long term BPV by discontinuously treating spontaneously hypertensive rats with valsartan. Discontinuous treatment reduced systolic blood pressure level but increased long term BPV. In addition, this treatment regimen failed to reduce arterial stiffness and induced a vascular hypertrophy without modification of elastin/collagen ratio. Discontinuous treatment also highly increased vascular fibronectin in parallel to αv integrin.In conclusion, a rise of both short- and long-term BPV leads to an increase in arterial stiffness, independently of blood pressure level. The structural changes at the origin of this increase in arterial rigidity involve different mechanisms, in which fibronectin and integrin α5 and αv play a key role
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Gagnon, Marie-Claude. "Sympathovagal influences on heart rate and blood pressure variability in highly trained endurance athletes." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24080.
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The evidence for an increase in resting vagal tone to explain the lower heart rate of endurance athletes remains controversial. This study used spectral analysis of heart rate (HRV) and blood pressure (BPV) variability to examine the vagal and sympathovagal influences on the sinus node in 12 endurance-trained athletes (A) and 10 age and sex-matched control subjects (C) (age: 26(1.2) yrs; VO2max: A: 68.2(2.1) vs C: 41.4(2.0) ml/kg/min; p $<$ 0.05). Continuous ECG and BP recordings were obtained during supine rest, sitting, controlled respiration (12 breaths/min), standing, exercise at heart rates of 100 and 130 beats/min, and after 5 and 15 minutes of seated recovery. No differences were observed between A and C in the vagal or high frequency (HF) components (48.0(4.0) vs 44.2(6.9) nu), in the low frequency (LF) components (55.8(6.9) vs 52.0(4.0) nu), or in the LF/HF ratios (1.72(0.4) vs 1.22(0.2)) of the HRV spectral components at rest or other experimental conditions, despite the lower resting heart rates of the A (53.1(1.8) vs 65.1(2.1) beats/min; p $<$ 0.05). Standing and exercise decreased the HF components and increased the LF/HF ratios similarily in both the A and C, controlled respiration induced similar rises in the HF component of HRV. Despite a significantly higher systolic BP in athletes, no difference was observed between A and C in the HF or LF components of either systolic or diastolic BPV. Exercise induced an increase in the HF component of BPV which was associated with the rise in breathing frequency. These results indicate a similar sinoatrial sympathovagal balance in A and C suggesting that training-induced bradycardia could result from an adaptation in the intrinsic sinoatrial properties. Also, endurance training does not appear to influence the beat-to-beat BPV.
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Diaz, Keith M. "Blood Pressure Variability: Relationship with Endothelial Health and Effects of an Exercise Training Intervention." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/183386.
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KinesiologyPh.D.
Purpose: Evidence has accumulated to show that blood pressure variability (BPV) has a striking relationship with cardiovascular (CV) risk. Despite the mounting evidence implicating BPV as a CV risk factor, scant attention has been paid to: (1) the mechanisms by which high BPV confers greater CV risk; and (2) the efficacy of non-pharmacologic treatment modalities in the attenuation of BPV. In order to address these two unresolved questions, the purpose of this dissertation was twofold. The purpose of study #1 was to investigate the association between measures of short-term BPV (24-hour BPV) and long-term BPV (visit-to-visit BPV) with markers of endothelial health in a cohort of African Americans in order to determine if increased BPV may confer greater CV risk by eliciting injury to the endothelium. The purpose of study #2 was to investigate the effects of a 6-month aerobic exercise training (AEXT) intervention on visit-to-visit BPV and 24-hour BPV in the same cohort of African Americans in order to provide the first available data on the efficacy of a non-pharmacologic treatment modality in the lowering of BPV. Methods: We recruited 72 African Americans who were sedentary, non-diabetic, non-smoking, and free of CV and renal disease. Before and after a 6-month AEXT intervention, office blood pressure (BP) was measured at 3 separate visits and 24-hour ambulatory BP monitoring (ABPM) was conducted to measure visit-to-visit BPV and 24-hour BPV, respectively. Right brachial artery diameter was assessed at rest, during flow-mediated dilation (FMD), and after nitroglycerin-mediated dilation (NMD). Peak and area under the curve (AUC) were calculated as measures of FMD and NMD, and the FMD/NMD ratio was calculated as a measure of endothelial function normalized by smooth muscle function. Fasted blood samples were obtained and were analyzed for circulating EMPs expressed as CD31+CD42- and CD62E+ EMPs. Results: In study #1, participants with higher 24-hour diastolic BPV (DBPV) had significantly lower CD31+CD42- EMPs compared to participants with lower 24-hour DBPV. When categorized according to visit-to-visit DBPV, participants with higher visit-to-visit DBPV had a significantly lower FMD/NMD ratio, and significantly higher %NMDpeak and NMDAUCs compared to participants with lower visit-to-visit DBPV. When analyzed as continuous variables, 24-hour mean arterial pressure variability (MAPV) was inversely associated with CD31+CD42- EMPs visit-to-visit DBPV was inversely associated with the FMD/NMD ratio and positively associated with %NMDpeak and NMDAUC; and 24-hour DBPV was positively associated with NMDAUC. All associations were independent of age, gender, BMI, mean BP, and pulse pressure. In study #2 investigating the effects of AEXT in 33 participants who completed the study, 24-hour DBPV and 24-hour MAPV were significantly increased after AEXT. The increase in 24-hour DBPV was independent of changes in BMI, mean BP, and self-reported sleep time. Heart rate variability (HRV) derived from ABPM was associated with the changes in 24-hour DBPV and 24-hour MAPV. There were no significant changes in visit-to-visit BPV after AEXT. Conclusions: The results from study #1 provide evidence that BPV is associated with vascular health as endothelial function was decreased in participants with high visit-to-visit DBPV, while smooth muscle function was increased in participants with higher visit-to-visit and 24-hour DBPV. The findings from study #2 show that 6-months of AEXT do not elicit beneficial changes in BPV. The finding of an association between changes in 24-hour BPV with HRV could indicate, however, that changes in activity levels during ABPM, in part, contributed to the observed changes in 24-hour BPV.
Temple University--Theses
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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.
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Anxiety and its cognitive component of worry have been related to exaggerated cardiovascular reactivity and delayed recovery to laboratory stressors, and to increased risk of cardiovascular disease. Previous research on the anxiety-cardiovascular system relationship, including data from Knepp and Friedman (2008), are included to support this project. Two experiments were completed during the course of this study. The first consisted of two peripheral-based body positioning tasks. The second experiment used an active versus passive sympathetic stress task paradigm (mental arithmetic, hand cold pressor). Subjects were nonsmokers free of cardiovascular and neurological disease. Trait worry was examined through the Penn State Worry Questionnaire (PSWQ). Blood pressure recordings and cardiac recordings through ECG and ICG were done in each experiment during seven epochs: an anticipatory baseline with three baselines preceding and three recovery periods following each task. Repeated measures analysis was run on all cardiovascular measures. In the first experiment, high worriers had worsened blood pressure reactivity to task. The second experiment found that high worriers had increased stroke volume across all epochs. There were mixed findings in the studies relating to subjects acclimated to the laboratory experience. Future directions of research relating anxiety, worry, and cardiovascular risk factors are discussed.Ph. D.
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O'Rielly, Susan. "What Explains Variability in Blood Pressure Readings? Multilevel Analysis of Data from 8,731 Older Adults in 20 Ontario Communities." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20308.
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Title:
What explains variability in blood pressure readings? Multilevel analysis of data from 8,731 older adults in 20 Ontario Communities
Objectives:
Despite universal healthcare and drug coverage for adults aged 65 and over in Ontario, hypertension, a treatable condition, remains uncontrolled among many older adults. Moreover, there are geographic disparities in blood pressure and hypertension within and across Canadian provinces and territories. Using baseline data collected on 8,731 older adults participating in the Cardiovascular Health Awareness Program (CHAP) in 20 randomly selected Ontario communities, we investigated associations between systolic blood pressure (SBP) and individual- and community-level characteristics, controlling for self-reported use of blood pressure medications.
Method:
Older adults were recruited via invitation by local family physicians, public advertising and word of mouth to attend community pharmacy sessions. During the sessions, trained older adult volunteers assisted participants to complete a cardiovascular disease risk factor questionnaire and blood pressure assessments using an automated blood pressure measuring device. The Postal Code Conversion File Plus was used to confirm residence within one of the 20 study communities. A multilevel linear regression analysis with participants nested within communities was used to determine which individual- and/or community-level characteristics were associated with measured systolic blood pressure level controlling for self-reported use of blood pressure medication.
Results:
4,706 participants (53.9%) reported the use of blood pressure medication. Mean systolic blood pressure (SBP) levels varied among the 20 communities from 128.1 mmHg to 134.7 mmHg for participants not using blood pressure medication and from 131.9 mmHg to 139.0 mmHg for participants using blood pressure medication. The intraclass correlation coefficients were very small: less than 0.2% of the total variance was between communities. Among participants not using blood pressure medication, SBP was associated with the following individual- level characteristics: age, sex, body mass index , smoking, physical activity, stress, fruit/vegetable intake, and alcohol consumption and the following community-level characteristics: community size, community growth and the Rurality Index. Among participants using blood pressure medication, SBP was associated with the following individual-level characteristics: age, sex, body mass index, diabetes, fruit/vegetable intake, alcohol intake and one community-level characteristic: community size. The significance and magnitude of these associations were modified by the use of blood pressure medication.
Conclusion:
The majority of the variability in blood pressure occurs at the individual-level. There are specific individual- and community-level factors that explain variability in blood pressure readings among communities. These results can be used to inform health promotion strategies to decrease mean levels of blood pressure among older adults.
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Saxon, LaDonna Christine Doster Joseph A. 1943. "Heart rhythm variability in persons with chronic pain." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-9037.
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Webb, Alastair John Stewart. "Determinants of medium-term blood pressure variability and the related risks of stroke and dementia." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:cd97daf5-c6d7-4386-94d7-a710d8ea5292.
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Visit-to-visit variability in blood pressure (BP) increases stroke risk, independent of mean BP. However, its physiological validity, the ideal method of measurement and the mechanisms increasing cardiovascular risk are unclear. In meta-analyses of individual patient data, I pooled associations between BP variability and risk of stroke, all cardiovascular events and death. I then determined antihypertensive drug-class differences in cardiovascular risk, intra-individual (I-VR) and inter-individual BP variability (M-VR). In 500 Oxford Vascular Study (OXVASC) patients undergoing thrice-daily home (HBPM) and awake ambulatory monitoring (ABPM), associations between mean, maximum or variability in BP (CV-BP) were determined with premorbid BP, hypertensive arteriopathy (creatinine, aortic stiffness, cognitive impairment, stroke versus TIA and leukoaraiosis) and cardiovascular events. In 200 patients, I determined associations with pulsatility or stiffness (pulse wave velocity) in cerebral and aortic vessels. There was a 21% and 27% increased risk of stroke and myocardial infarction per standard deviation of CV-SBP in 318700 patients, independent of mean SBP. In 244,479 patients, SBP variability was reduced by CCBs and diuretics within (I-VR=0.89, 95% CI=0.82-0.96, p=0.0001) and between individuals (M-VR 0.83, 0.77-0.89, p<0.0001), especially in the first year of treatment, explaining drug class differences in stroke risk (OR=0.76, 0.68-0.87, p<0.0001). In OXVASC, drug class differences on day-to-day SBP variability were greatest immediately after waking. Residual hypertension after treatment on HBPM but not ABPM (BP>135/85) predicted recurrent cardiovascular events (HR 2.82, 1.44-5.51, p=0.002 vs. 1.48, 0.68-3.23, p=0.33), reflecting stronger associations with premorbid BP and hypertensive arteriopathy, due largely to inaccuracy of ABPM in patients aged >65 years. Furthermore, day-to-day maximum and CV-SBP were associated with premorbid BP, hypertensive arteriopathy and cardiovascular events, with no additional predictive value of mean SBP when analysed with maximum SBP. Maximum SBP was greater in men and CV-SBP in women, whilst age and creatinine determined both. Increased stroke risk may partly be due to the association between BP variability and cerebral pulsatility, which was correlated with leukoaraiosis (p=0.01) and determined by aortic stiffness (p=0.016) and pulsatility (p<0.001). BP variability is clinically significant and physiologically valid, and is treatable with CCBs and diuretics. After TIA or minor stroke, HBPM best identifies residual hypertension and demonstrates the predictive value of BP variability and maximum BP, but associated arterial changes might explain some of the increased stroke risk.
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Rarick, Kevin Richard. "Cardiovascular end-organ damage in response to increased blood pressure variability : impact of oxidative stress." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/3370.
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Baroreflex sensitivity (BRS) is often reduced in elderly populations and patients with chronic cardiovascular diseases leading to a concomitant rise in blood pressure variability (BPV) that is associated with increased cardiovascular related morbidity and mortality. Thus, there is a need to better understand the mechanisms by which BPV causes cardiovascular end-organ damage. Animal studies using sinoaortic denervation (SAD) to increase BPV have demonstrated pathologic changes in the structure of the heart and blood vessels; however, there is a paucity of data investigating changes in functional measures of the heart and smaller, resistance type arteries. Furthermore, the pathogenic mechanisms involved in BPV-induced cardiovascular end-organ damage remain unknown. Baroreceptor denervation results in multiple cardiac stressors, many of which are associated with production of reactive oxygen species. Oxidative stress is known to promote cardiovascular end-organ damage but it is unclear if it plays a role in models of increased BPV. Thus, this study was designed to investigate the functional responses of smaller resistance type arteries and the heart to chronic exposure to enhanced BPV. In addition, the role of oxidative stress on these functional responses in a normotensive rat model of increased BPV was also investigated. Rats were subjected to either SAD surgery or a sham procedure and were observed for six weeks. To determine the role of oxidative stress, SAD rats were either treated with the superoxide dismutase mimetic tempol or left untreated. During the observation period, mean blood pressure remained normotensive, whereas baroreflex sensitivity was reduced and BPV increased two to three fold. Weekly in vivo assessment of vascular function of the long posterior ciliary artery (LPCA) demonstrated a significant reduction in endothelial-dependent dilation starting three weeks after SAD surgery compared to the sham group. Endothelial-independent dilation was not affected by SAD. Structural changes were not evident in the LPCA following SAD. However, structural (wall thickness, wall area, and wall area/lumen area ratio) and functional (strain and distensibility) changes were observed in the aorta. Cardiac structural (hypertrophy) and functional (diastolic dysfunction) effects were also evident following six weeks of increased BPV. Antioxidant treatment with tempol did not have any effect on the SAD-induced increase in BPV or decrease in BRS. Nevertheless, chronic tempol treatment prevented or reduced the cardiovascular end-organ damage (endothelial-dependent vascular dysfunction, decreased aortic distensibility, cardiac and vascular hypertrophy, and cardiac dysfunction) observed in the untreated SAD group. These findings suggest that the pathology observed following SAD is at least partly mediated by oxidative stress. Antioxidant treatment in patients with increased BPV (e.g., hypertension, diabetes, heart failure) may prevent or ameliorate cardiovascular end-organ damage and reduce the overall risk for cardiovascular disease events.
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Xie, Bingjiao, and 謝冰姣. "Association of arterial stiffness and blood pressure variability with silent brain lesions in healthy hypertensive elderly Chinese." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/212629.
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McLaren, Andrew. "Heart rate and blood pressure variability : association with white matter lesions and cognitive function following stroke." Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/965.
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Dementia presents a significant health care burden. Older post-stroke patients suffer high rates of dementia. Subcortical ischaemia may be an important mechanism of cognitive decline, particularly in older patients with cerebrovascular disease. It is hypothesised that abnormal heart rate and blood pressure variability will increase white matter lesion volume through hypoperfusion. This may lead to a subcortical pattern of cognitive decline characterised for example by deficits in attention and concentration. Stroke patients aged > 75 years and free of dementia had a series of cardiovascular autonomic, brain imaging and neuropsychometric investigations performed more than three months following incident stroke. Annual neuropsychometric assessment included CAMCOG score and measures of reaction time and concentration using a series of visual and numerical tasks presented on computer (Cognitive Drug Research Assessment System). Autonomic function is impaired in older stroke patients in the long term after stroke. These deficits are weakly associated with cross-sectional measures of sub-cortical performance but do not predict subsequent decline in cognitive function. Twenty-four hour blood pressure variability is associated with white matter disease and excessive nocturnal dipping is associated with impaired cognitive function. Again blood pressure variability does not help predict subsequent change in white matter lesion burden or cognitive function. This study provides limited support for the hypoperfusion theory of post-stroke cognitive impairment. However it does not indicate a role for heart rate and blood pressure variability in the mechanism of increasing white matter disease or decline in cognition in the two years following stroke.
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Korhonen, Iikka. "Methods for the analysis of short-term variability of heart rate and blood pressure in frequency domain /." Espoo : Technical Research Centre of Finland, 1997. http://www.vtt.fi/inf/pdf/publications/1997/P316.pdf.
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Bourassa, K. J., K. Hasselmo, and D. A. Sbarra. "Heart Rate Variability Moderates the Association Between Separation-Related Psychological Distress and Blood Pressure Reactivity Over Time." SAGE PUBLICATIONS INC, 2016. http://hdl.handle.net/10150/621209.
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Divorce is a stressor associated with long-term health risk, though the mechanisms of this effect are poorly understood. Cardiovascular reactivity is one biological pathway implicated as a predictor of poor long-term health after divorce. A sample of recently separated and divorced adults (N = 138) was assessed over an average of 7.5 months to explore whether individual differences in heart rate variability—assessed by respiratory sinus arrhythmia—operate in combination with subjective reports of separation-related distress to predict prospective changes in cardiovascular reactivity, as indexed by blood pressure reactivity. Participants with low resting respiratory sinus arrhythmia at baseline showed no association between divorce-related distress and later blood pressure reactivity, whereas participants with high respiratory sinus arrhythmia showed a positive association. In addition, within-person variation in respiratory sinus arrhythmia and between-persons variation in separation-related distress interacted to predict blood pressure reactivity at each laboratory visit. Individual differences in heart rate variability and subjective distress operate together to predict cardiovascular reactivity and may explain some of the long-term health risk associated with divorce.
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Kiru, Gayithri. "Investigating the roles of peripheral and central blood pressure and blood pressure variability on the size and growth rate of AAAs in the AARDVARK trial and the CAVE sub-study." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/53377.
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The AARDVARK (Aortic Aneurysmal Regression of Dilation: Value of ACE-Inhibition on RisK) trial was designed to investigate whether ACE-inhibition reduces the growth rate of small abdominal aortic aneurysms (AAA), independent of blood pressure (BP) lowering. A cohort of patients from the AARDVARK trial contributed data to the CAVE sub-study which investigated the roles of peripheral and central BP and 3 measures (standard deviation, coefficient of variation and variation independent of the mean) of visit-to-visit BP variability (BPV) of peripheral and central BPs on the size and growth rate of the diameters of small AAAs. Subjects aged ≥55 years with AAA diameter 3.0–5.4 cm were randomised 1:1:1 to receive perindopril 10 mg, or amlodipine 5 mg, or placebo. Three standardised BP measurements and an AAA ultrasound scan were performed at every trial visit (every 3-6 months over 2 years). Five of 14 trial sites were provided with a BP+ machine which measures both peripheral and central BP. Nine sites collected peripheral BP only with an Omron machine. BPV was based on readings taken after 3 months to avoid confounding from the impact of trial treatments. The primary outcome of the AARDVARK trial was AAA diameter growth (based on external antero-posterior ultrasound measurements in the longitudinal plane), determined by multi-level modelling. 224 patients were randomised between 2011 and 2013 to receive either placebo (n = 79), perindopril (n = 73), or amlodipine (n = 72). Mean baseline age, peripheral BP and AAA size among the 224 patients who contributed peripheral BP data were 71.3 years, 131.5/77.7 mmHg and 4.0cm (external diameter) respectively and were not significantly different from the 139 patients who also contributed central BP data. No significant differences in the modelled annual growth rates were apparent among the 3 randomised groups [placebo 1.68 mm (SE 0.2), perinodopril 1.77 mm (0.2), and amlodipine 1.81 mm (0.2), respectively]. The estimated difference in annual growth between the perindopril and placebo group was 0.08 mm (CI 20.50, 0.65). No evidence of an association was found between peripheral or central BP and AAA size at baseline or AAA growth in-trial. However, significant associations were found between central (but not peripheral) BPV and AAA growth using linear regression after adjustment for possible confounders. This association was stronger for central diastolic than systolic BPV. Evidence of a dose-response effect (albeit underpowered due to this comparison being restricted to quartiles) was apparent, with patients having the most variable central BP exhibiting the highest AAA growth rates. In the AARDVARK trial, small AAA growth rates were lower than anticipated thereby reducing the power of the trial, but there was no apparent impact of perindopril compared with placebo or placebo and amlodipine combined on AAA growth rates, despite more effective BP lowering among those allocated to perindopril. However by contrast, in the CAVE sub-study we showed a significant association between all 3 measures of central BPV and AAA growth despite the small sample size and limited numbers of visits. A larger study is required to confirm these results.
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Crisalli, Joseph A. M. D. "Baroreflex Sensitivity after Adenotonsillectomy in Children with Obstructive Sleep Apnea during Wakefulness and Sleep." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384334068.
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Fernandes, Vargas Pedro Miguel. "Acute cardiovascular responses to slow and deep breathing." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/16415.
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Slow and deep breathing (SDB) has long been regarded as a nonpharmacological method for dealing with several physiological and emotional imbalances, and widely used for relaxation purposes. There is, however, limited understanding of the putative mechanisms by which SDB acutely impacts the cardiovascular and autonomic systems to elicit chronic adaptations. The present thesis explored how the manipulation of breathing pattern and intrathoracic pressure during SDB could further the understanding of the regulatory mechanisms that underpin the acute cardiovascular response to SDB. This thesis makes an original contribution to the existing knowledge by reporting a previously undescribed inversion of normal within-breath (inspiration vs. expiration) left ventricular stroke volume (LVSV) pattern for breathing frequencies < 8 breaths∙min-1. This finding might reflect the influence of a lag between enhanced right atrial filling and right ventricular stroke volume during inspiration, and its expression in left ventricular stroke volume; this lag results from the time required for blood to transit the pulmonary circulation. Furthermore, blood pressure variability (BPV) was reduced significantly at the lowest breathing frequencies, likely due to the involvement of baroreflex mediated responses. The pattern of responses was consistent with the buffering of respiratory-driven fluctuations in left ventricular cardiac output (Q̇) and arterial blood pressure (ABP) by within breath fluctuations in heart rate (fc), i.e., respiratory sinus arrhythmia (RSA) (Chapter 4). Chapter 5 demonstrated that magnifying negative intrathoracic pressure with inspiratory loading during SDB increased inspiratory pressure-driven fluctuations in LVSV and fc, and enhanced Q̇, independently of changes in VT and fR. The data support an important contribution to the amplification of RSA, during SDB, of previously underappreciated reflex, and/or 'myogenic', cardiac response mechanisms. The findings in Chapter 6 confirmed that inspiratory loading during SDB amplified the effects observed with un-loaded SDB (reported in chapter 5). In contrast, expiratory loading increased ABP and attenuated RSA, LVSV and Q̇ during SDB. A lower RSA for higher ABP, supports the presence of a formerly underappreciated contribution of sinoatrial node stretch to RSA, and throws into question the clinical benefits of expiratory resisted SDB, particularly in hypertensive populations. In conclusion, the findings of the present thesis provide novel information regarding the mechanisms contributing to acute cardiovascular response to SDB. These new insights may contribute to the development of more effective SDB interventions, geared towards maximising the perturbation to the cardiovascular control systems.
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Yu, Jin, Megumi Funakubo, and Kazue Mizumura. "Effects of Lowering Barometric Pressure and Ambient Temperature on Blood Pressure, Heart Rate and Pulse Interval Variability in Conscious Rats(RIEM Conference Ⅱ,2003)." Research Institute of Environmental Medicine, Nagoya University, 2003. http://hdl.handle.net/2237/7614.
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Campbell, Thomas George. "Ambulatory physiological assessment : an ergonomic approach to the dynamic work environment and temporal variability in heart rate variability, blood pressure and the cortisol awakening response." Thesis, Edinburgh Napier University, 2014. http://researchrepository.napier.ac.uk/Output/452967.
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Aim: The aim of this thesis was to investigate the psychophysiological response to the dynamic working environment within a cohort of higher education employees via ambulatory assessment of psychosocial and physiological measures. Methods: Data was collected from two observational studies. Study one employed a cross-sectional design to investigate relationships between work-related psychosocial hazard, work-time heart rate variability, blood pressure, and the cortisol awakening response. Consideration was given to occupation type and acute work-related demand. Study two, a single-subject case study, employed an experience sampling methodology to peform a 24 hour assessment over 21 days. Workload, affect and demand were sampled during working hours, while heart rate variability and physical activity were continually sampled (24 hours), with salivary cortisol, being sampled at 3 time points during the awakening period. This study also investigated some of the methodological issues associated with ambulatory assessment of both heart rate variability and the cortisol awakening response. Findings: Chronic work-related demand was found to be positively associated with sympathetic dominance of the autonomic nervous system. Acute work-related demand was associated with ambulatory heart rate variability during work time and evening time whilst the rise in salivary free cortisol over the immediate post awakening period varies according to acute anticipatory demand and prior day's workload. Substantial intra--individual variation in both the cortisol awakening response and ambulatory heart variability was found to occur across work-days. Work time activity levels accounted for little of the variation in ambulatory heart rate variability and blood pressure. The cortisol awakening response was associated with both heart rate variability and nocturnal movement in the latter stage of sleep. Conclusion: Attending to the psychophysiological response to work at the individual level by means of ambulatory assessment appears to provide a useful means of assessing the balance between employee and environment. This could have significant implications for work design, employee selection and targeting of workplace interventions.
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Alomari, Abdul-Hakeem Hussein Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Spectral analysis of arterial blood prssure and stroke volume variability: the role of Calcium channel blockers and sensitizers." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/43923.
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In this thesis, we included results from two studies. The first one considered the effects of the blood volume changes, during blood donation, on the heart rate variability (HRV) measured, non-invasively, form electrocardiographic (ECG) and photoplethysmographic (PPG) signals. Our results showed that, during blood donation, there were no significant changes in the pulsatile area of PPG signal, while heart rate increased. No significant changes were noticed in HRV extracted from both signals. Error analysis between the HRV extracted from ECG and peak interval variability (PIV) suggested that the error during blood donation was increased which means that the use of PIV extracted from PPG signal, used as a replacement diagnostic tool in clinical applications, needs further investigations and should be carefully studied in non-stationary cardiovascular situations such as blood donation. The imbalance between the two branches of the autonomic nervous system, sympathetic and parasympathetic, vagal, may result in a harmful activation of myocardial tissues which cause arrhythmias and sudden cardiac death. Although the study of the sympathovagal balance have been attracting many researchers, further studies are needed to elucidate the effects of many kinds of drugs on the autonomic modulation of the cardiac muscle, specifically, the cells of sinoatrial (SA) node. The aim of the second part of this thesis was to assess the effects of calcium channel blocker (Verapamil), calcium channel sensitizer (Levosimendan), calcium chloride (CaCl2), the combinations of verapamil/ CaCl2, levosimendan/ CaCl2, and noradrenaline infusion on beat-to-beat cardiovascular variability represented, in this research, by systolic blood pressure variability (SBPV), and stroke volume variability (SVV) signals. We used Fat Fourier Transform (FFT) to evaluate the power spectral density of the fluctuations in both signals to evaluate the effects of short-term treatments with those drugs on the sympathovagal balance in normal rats. Then, we compared the spectra obtained from SBPV and SVV to decide which of these fluctuations along with corresponding spectrum was more able to provide a clear feedback about the autonomic nervous system. Our data suggests that there were a significant correlations between low- (LF), mid- (MF), and high-frequency (HF) spectra obtained from SBPV and SVV except between the HF spectra estimated from after the infusion of levosimendan where a poor correlation (r = 0.530, p = 0.281) was noticed. This that both HF components obtained provide different information regarding the autonomic nervous system modulation of the SA node cells, while the results obtained from the rest of experiments showed that both signals provide same information about the modulation of sympathetic and parasympathetic tone due to all stages of different drugs infusion studied in this thesis. Besides that, we found that both spectra may be used to track the fluctuations in the cardiac output as a result of the drugs infusion.
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Saxon, LaDonna Christine. "Heart rhythm variability in persons with chronic pain." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9037/.
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The present study evaluated the utility of heart rhythm coherence (HRC) feedback to reduce the reported pain intensity of patients enrolled in a multimodal pain management program. Participants were recruited and assigned to a usual treatment group (UT) or a heart rhythm coherence feedback group (UT+HRC). It was hypothesized that UT+HRC participants who achieved heart rhythm coherence would report a reduction of pain intensity, as measured by the McGill Pain Inventory. For those whose pain intensity decreased, it was also expected that their self reported levels of depression as measured by the Beck Depression Inventory-Second Edition and state anger as measured by the State Trait Anger Inventory would decrease. It is also hypothesized that with a reduction in pain levels, anger, and depression, blood pressure would also decrease among those who had high blood pressure prior to the intervention. Multivariate analyses of variance (MANOVA) were used to investigate the relationship between treatment condition, coherence status and pain levels. A series of independent t-tests were utilized to investigate the change in pain, depression, and state anger from baseline to posttest, followed by Pearson product moment correlation coefficients on difference scores to understand the relationship between the outcome variables for Hypothesis 2. Standard multiple regression analyses were computed using difference scores to determine if the outcome measures were significant predictors of systolic blood pressure and diastolic blood pressure. Results indicated a failure to reject the null with regard to hypothesis one. No relationship between treatment assignment, coherence status or pain levels were found. Hypothesis 2 was partially supported. Although there was a positive significant relationship between depression and anger when utilizing difference scores, these affective measures were not related to difference scores on either pain measure. In regard to Hypothesis 3, there was also a failure to reject the null. None of the outcome measures utilized in this study emerged as being significantly related to changes in systolic or diastolic blood pressure. Limitations of the study and implications for future research are offered.
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Plch, Miroslav. "Stanovení parametrů křivky krevního tlaku." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219532.
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The thesis includes a general introduction to monitoring and measurement of blood pressure of horses, the design of algorithms for pressure curve detection and the calculation of respiratory variabilities in mechanical ventilation under anaesthesia. The first two chapters focus on anatomy, on characteristics of blood flow and on vascular system. Then it deals with the measurement of blood pressure, monitoring of a horse under anaesthesia and it describes particular thermodynamic parameters. In the following part of the thesis, the methods of pressure curve detection are described. The last part contains the description of an algorithm designed for detection of pressure curve of horses in the environment of the program LabVIEW. The program calculates, displays and saves variabilities of systolic pressure, pulse volume, pressure amplitude, pulse frequency, peripheral resistance and vascular expansion from the detected values.
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Nafz, Benno. "Blutdruckvariabilität und Blutdruckregulation." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2004. http://dx.doi.org/10.18452/13936.
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Die mittlere Höhe des arteriellen Blutdruckes (AP) ist von zentraler Bedeutung für das kardiovaskuläre Risiko Hochdruckkranker. Zusätzlich zeigen neuere Untersuchungen, daß Änderungen der Blutdruckdynamik eine wichtige Rolle in der Entwicklung hypertonieassoziierten Endorganschäden zukommt. Die Blutdruckvariabilität scheint in diesem Zusammenhang sogar einen eigenständigen Risikofaktor zu bilden. Der Einfluß kurzfristiger Blutdruckschwankungen auf zentrale Mechanismen der Langzeitblutdruckregulation, wie beispielsweise die renale Elimination von Natrium und Wasser, ist weitgehend unbekannt. Unsere Untersuchungen zeigen, daß schnelle Blutdruckschwankungen (BPO) kaum von der renalen Autoregulation der Durchblutung (RBF) unterdrückt werden können und zu Oszillation im Harnzeitvolumen führen. Es ist daher wahrscheinlich, daß BPO intrarenale System der Blutdruckregulation (wie beispielsweise das Renin-Angiotensin-System oder die schubspannungsabhängige Freisetzung von Stickoxid) modulieren können. Um diese Hypothese zu testen wurde der Einfluß von 0,1Hz BPO auf die Entwicklung eines renovaskulären Hypertonus untersucht. BPO um 85mmHg senkten signifikant die Plasmareninaktivität, erhöhten die tägliche Ausscheidung von Wasser, Natrium und Kalium und induzierten einen transienten Anstieg der Nitratspiegel im Urin wobei eine deutliche Senkung des arteriellen Blutdruckes beobachtet wurde.The average level of arterial blood pressure (AP) is a major determinant of future cardiovascular complications in hypertension. In addition, recent investigations demonstrate that the dynamic properties of BP are of significant importance for the development of hypertension - related end organ damage in patients. Thus, hypertension - related changes in blood pressure dynamics seem to establish an independent risk factor for cardiovascular complications. Little is known regarding the influence of such short - term changes in AP on kidney function, a crucial control element for long - term AP regulation. Our investigations show that fast blood pressure oscillations (BPO) are not effectively buffered by renal blood flow autoregulation and induce oscillations in urine flow. It seems, therefore, likely that AP fluctuations can modulate intrarenally located systems involved in blood pressure regulation (e.g., renin release or shear stress dependent release of endothelium derived nitric oxide). To test this hypothesis we investigated the impact of induced BPO with a frequency of 0.1Hz on the onset of renovascular hypertension. BPO around 85mmHg significantly decreased plasma renin activity, enhanced 24h fluid, sodium and potassium excretion, and induced a transient increase in urinary nitrate excretion, thereby, attenuating renovascular hypertension.
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DEL, PINTO RITA. "Visit-to-visit Systolic Blood Pressure Variability and Clinical Implications in a High-Risk Hypertensive Population: an Analysis of the SPRINT Data." Doctoral thesis, Università degli Studi dell'Aquila, 2020. http://hdl.handle.net/11697/144606.
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Aim. The prognostic significance of blood pressure variability (BPV) for the occurrence of cardiovascular (CV) events and mortality is still debated. Differences in its methodological assessment and in patients’ characteristics have been both indicated as potential explanations to the discrepant findings. We used the Systolic Blood Pressure Intervention Trial (SPRINT) dataset to explore this unresolved issue.
Methods. We applied three protocols that differed by timing and number of study visits to calculate the same index (coefficient of variation, CoV, %) of long-term (visit-to-visit) systolic BPV: 1) quarterly until outcome occurrence, including monthly assessment during the 3-months titration period; 2) quarterly until outcome occurrence, excluding titration period; and 3) quarterly for 1 year, excluding titration period. Outcomes of interest were primary events and all-cause mortality. Crude and progressively adjusted Cox proportional hazard models were used to assess the risk of outcomes according to the three estimates of visit-to-visit systolic BPV.
Results. An optimal visit-to-visit systolic BPV associated with lower incidence of the primary outcome (CoV 5-10%) and all-cause mortality (CoV ≤8%), or any of the two (CoV 5-11%), was identified according to the first two estimates only. This effect was independent of mean systolic BP. Optimal visit-to-visit systolic BPV appeared to confer additional protection to intensive BP lowering. Conversely, different BPV apparently worsened CV risk among standard-treated patients. Clinical correlates of suboptimal BPV included older age, female gender, non-White ethnicity, smoke, and pre-existing CV and renal disease.
Conclusions. Visit-to-visit systolic BPV might add prognostic value to the estimation of CV risk in high-risk, non-diabetic hypertensive patients, but the protocol adopted for its calculation is crucial. An effort to standardize BPV assessment is worthwhile.
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Benešová, Lenka. "Vyhodnocení variability rychlosti pulzové vlny." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400981.
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This diploma thesis deals with the variability of pulse wave velocity. It studies the variability of cardiovascular signals. It presents the research of measurement of pulse wave velocity and its analysis in physiology and pathological physiology. Applies spectral analysis in Matlab to a data set. It evaluates and reviews the results of this analysis
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Kuwabara, Junko. "Cross-sectional study of the association between day-to-day home blood pressure variability and visceral fat area measured using the dual impedance method." Kyoto University, 2019. http://hdl.handle.net/2433/242347.
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Swaminathan, Krishnan. "The Effects of Aldosterone blockade on Blood pressure, Endothelial function, Glycaemic control, Key hormomes and Heart Rate Variability in Hypertensive patients with Type 2 Diabetes." Thesis, University of Dundee, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500634.
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Steinhorst, Ana Maria Pasquali. "Associação entre síndrome das apnéias-hipopnéias do sono e variabilidade da pressão arterial." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/80065.
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Introdução: O desenvolvimento de hipertensão arterial e doença cardiovascular relacionado à síndrome das apnéia obstrutiva do sono (SAOS) parece estar relacionado a alterações sobre a regulação autonômica cardiovascular. Este estudo investigou se a SAOS influência a variabilidade da pressão arterial (PA). Métodos: Estudo transversal, com pacientes hipertensos que foram submetidos à polissonografia nível III, por meio de um monitor portátil de uso domiciliar para detectar SAOS (índice de apnéia-hipopnéia (IAH) ≥ 10). A variabilidade da PA foi avaliada pela taxa de variação da pressão arterial no tempo (índice “time rate” - a primeira derivada da pressão arterial ao longo do tempo) e desvio padrão (DP) da PA obtidos dos dados da monitorização ambulatorial da pressão arterial (MAPA). Análises univariadas e multivariadas foram utilizadas para testar a associação entre a SAOS, IAH e variabilidade da pressão arterial. Resultados: Os pacientes com SAOS (n = 57) eram mais velhos, apresentavam pressão arterial mais elevada e maior duração da hipertensão do que pacientes sem SAOS (n = 50). Não houve nenhuma associação consistente entre o diagnóstico de SAOS e variabilidade da PA aferida pelo DP e pela taxa de variação da PA no tempo, tanto na análise univariada como após o ajuste para idade, IMC e respectiva medida de PA na MAPA. Não houve correlação significativa entre o AIH e os índices de variabilidade da PA em um modelo de regressão linear múltipla, controlando para idade, IMC e PA correspondente. Conclusão: SAOS não influencou a variabilidade da pressão arterial, aferida por estes métodos, em pacientes com hipertensão.Background The risk of obstructive sleep apnea syndrome (OSAS) for the development of hypertension and cardiovascular disease may be intermediate by influence over autonomic cardiovascular regulation. This study investigated if OSAS influences blood pressure (BP) variability. Methods In a cross-sectional study, patients with hypertension underwent level III polysomnography by means of a home portable monitor to detect OSAS, (apnea-hypopnea index (AHI) ≥10). BP variability was assessed by the time rate index (the first derivative of BP over time) and standard deviation (SD) of BP measured by 24-h ambulatory blood pressure measurement (ABPM). The association between OSAS, AHI and blood pressure variability was tested by univariate and multivariate methods. Results: Patients with OSAS (n = 57) were older, had higher blood pressure, and longer duration of hypertension than patients without OSAS (n = 50). There was no consistent association between the diagnosis of OSAS and BP variability assessed by the time-rate index and SD both in the univariate and after adjustment for age, BMI and the respective BP. There was no significant correlation between AIH and the indexes of BP variability in a multiple linear regression model controlling for age, BMI and the corresponding BP. Conclusion OSAS does not influence blood pressure variability in patients with hypertension.
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Westerlund, T. (Tarja). "Thermal, circulatory, and neuromuscular responses to whole-body cryotherapy." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514290435.
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Abstract
The purpose of this study was to examine thermal (body temperature, thermal sensation and comfort ratings), circulatory (blood pressure, heart rate variability) and neuromuscular performance responses to whole-body cryotherapy (WBC, -110 °C).
Altogether 66 healthy subjects were exposed to WBC for two minutes. The acute and long-term changes were examined, when the subjects were exposed to WBC three times a week during three months.
Skin temperatures decreased very rapidly during WBC, but remained such a high level that there was no risk for frostbites. The effects on rectal temperature were minimal. Repeated exposures to WBC were mostly well tolerated and comfortable and the subjects became habituated at an early stage of trials. WBC increased both systolic (24 mmHg) and diastolic (5 mmHg) blood pressures temporarily. Adaptation of blood pressure was not found during three months. The acute cooling-related increase in high-frequency power of RR-intervals indicated an increase in cardiac parasympathetic modulation, but after repeated WBC the increase was attenuated. The repeated WBC exposure-related increase in resting low frequency power of RR-intervals resembles the response observed related to exercise training. There are signs of neuromuscular adaptation, especially in dynamic performance. A single WBC decreased flight time in drop-jump exercise, but after repeated WBC these changes were almost vanished. This adaptation was confirmed by the change of the activity of the agonist muscle, which increased more and the change of the activity of antagonist muscle, which increased less/did not change after repeated WBC indicating reduced co-contraction and thus, neuromuscular adaptation.
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Fietze, Ingo. "Barorezeptorsensitivität, Herzfrequenzvariabilität und Blutdruckvariabilität bei Patienten mit einem milden-moderaten und schweren obstruktiven Schlafapnoe Syndrom und bei gesunden Probanden." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2003. http://dx.doi.org/10.18452/13866.
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Barorezeptorsensitivität, Herzfrequenzvariabilität und Blutdruckvariabilität bei Patienten mit einem mild-moderaten Schlafapnoe Syndrom und bei gesunden Probanden Die Behandlung von Patienten mit einem mild-moderaten obstruktiven Schlafapnoe Syndrom (OSAS) wird von der klinischen Symptomatik und dem Herzkreislaufrisiko bestimmt. Wir konnten nachweisen, dass bei einem mild-moderaten OSAS unter der Beatmungstherapie neben der Beseitigung der nächtlichen Atmungsstörung auch eine Änderung der Mikrostruktur des Schlafes (Arousal) und der Müdigkeit am Tage zu verzeichnen ist. Das Herzkreislaufrisiko untersuchten wir anhand noninvasiver Parameter der sympathovagalen Balance. Dazu wurden die Herzfrequenzvariabilität (HRV), die Blutdruckvariabilität (BDV) und die Barorezeptorsensitivität (BRS) im Zeit- und Frequenzbereich bestimmt und diese Größen bei Patienten mit einem mild-moderaten OSAS im Vergleich zu gesunden Probanden als auch der Effekt einer CPAP-Therapie - im Schlaf als auch am Tage - analysiert. Bei gesunden Probanden fanden wir eine HRV- und BRS-Abnahme sowie eine BDV-Zunahme im REM- gegenüber dem NREM-Schlaf. OSAS Patienten haben im Vergleich zu Gesunden eine niedrigere BRS im NREM und eine erhöhte BDV sowohl im REM- als auch NREM-Schlaf. CPAP führt beim OSAS zu einer Abnahme der Herzfrequenz und Zunahme der BRS, vornehmlich im NREM Schlaf und bei zusätzlich bekannter Hypertonie. Die HRV nimmt ab und die BDV zu, jeweils unabhängig vom Schlafstadium bzw. einer bestehenden Hypertonie. Am Tage zeigt sich nur ein Kurzzeiteffekt hinsichtlich Zunahme der BRS und HRV. Dieser Effekt ist vom Ausmaß des OSAS und dem Vorhandensein einer Hypertonie abhängig und nach 4 Wochen Therapie nicht mehr nachweisbar. Untersucht man den Effekt der Beatmungstherapie auf HRV, BDV und BRS bei gesunden Probanden im Akutversuch, dann findet man eine Erhöhung des Blutdruckes bei Abnahme der Herzfrequenz und Zunahme der BRS. HRV, BDV und BRS als Parameter für das kardiovaskuläre Risiko zeigen nachweisbare Veränderungen bei Schlafapnoe Patienten, auch wenn nur ein mild-moderates OSAS vorliegt. Ein Therapieeffekt lässt sich anhand dieser Parameter auch nachweisen, wobei ein vorhandener Akuteffekt von Überdruckbeatmung auf HRV, BDV und BRS unabhängig von einem OSAS zu berücksichtigen ist.Baroreceptor sensitivity, heart-rate variability, and blood-pressure variability in patients with mild to moderate sleep apnoea syndrome, and in healthy controls The treatment of patients with mild to moderate obstructive sleep apnoea syndrome, OSAS, is determined by the clinical symptom complex and by the cardiovascular risk. In patients with mild to moderate OSAS who received therapy in the form of assisted ventilation, we succeeded in evidencing that it is possible to influence the microstructure of sleep (i.e., of arousal) as well as fatigue experienced during the day, in addition to eliminating nocturnal respiratory disturbance. We investigated the cardiovascular risk by examining non-invasive parameters for sympathovagal balance. Therefore we analyzed heart-rate variability (HRV), blood-pressure variability (BPV), and baroreceptor sensitivity (BRS) over time and frequency ranges in patients with mild to moderate OSAS, in comparison to healthy controls. We likewise assessed the effects of CPAP therapy on these parameters, both during sleeping as well as non-sleeping hours. Among healthy test subjects, we determined decreases in HRV and BRS, as well as increase in BPV, during REM sleep, in comparison to NREM sleep. In comparison to healthy controls, OSAS patients have lower BRS during NREM and increased BPV in both REM and NREM sleep. In OSAS patients, CPAP leads to a decrease in heart rate and increase in BRS, especially in NREM sleep and in patients for whom hypertension is also known. HRV diminishes and BPV increases, in both cases regardless of the sleep stage or presence or absence of hypertension. During the day, only a short-term effect becomes apparent with respect to increases in BRS and HRV. This effect depends on the extent of OSAS and on the existence of hypertension; after four weeks of therapy, the effect is no longer in evidence. Acute testing of the effect of assisted ventilation on HRV, BPV, and BRS among healthy controls discloses increase in blood pressure, accompanied by decrease in heart rate and increase in BRS. HRV, BPV, and BRS as parameters for cardiovascular risk reveal evidence of alterations in sleep-apnoea patients, even for those suffering only from mild to moderate OSAS. Therapeutic effects are also in evidence on the basis of these parameters, whereby an existing acute effect of positive-pressure ventilation on HRV, BPV, and BRS regardless of OSAS must also be taken into account.
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Moreira, Nídia Maria Gomes. "Efeitos da effleurage de diferentes pressões na função cardíaca." Bachelor's thesis, [s.n.], 2014. http://hdl.handle.net/10284/4324.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaObjectivo: Determinar os efeitos da effleurage de diferentes pressões na função cardíaca. Metodologia: Foram seleccionadas 30 pessoas com as idades compreendidas entre os 20 a 25 anos todos do género masculino e sem patologias. Estes jovens foram divididos aleatoriamente em três grupos: grupo controlo (GC) (N=10), grupo effleurage superficial (GES) (N=10) e grupo effleurage profunda (GEP) (N=10). Foi utilizado um metrónomo para monitorizar a respiração, tendo sido utilizado um polar e um esfigmomanómetro electrónico para a avaliação da variabilidade da frequência cardíaca (VFC), frequência cardíaca (FC) e pressão arterial (PA). Todos os indivíduos foram analisados quanto a estes parâmetros no momento antes e após uma massagem de effleurage a 10 minutos nas costas. Resultados: O índice SDNN aumenta significativamente no GES após a aplicação da massagem (p<0,05). A média da FC apresentou valores significativos menores nos grupos experimentais GES e GEP em relação ao controlo, enquanto a pressão arterial diastólica (PAD) aumentou. Conclusão: A effleurage superficial parece ter tendência a produzir uma maior activação vagal. Objective: To determine the effects of effleurage from different pressures in cardiac function. Methodology: Thirty people were selected between the ages of 20 to 25 years all males and without pathologies. These young men were randomly divided into three groups: control group (GC) (N=10), superficial effleurage group GES (N=10) and deep effleurage group GEP (N=10). A metronome was used to monitor respiration, having been used the polar and an electronic sphygmomanometer for objective assessment of heart rate variability (HRV), heart rate (HR) and blood pressure (BP). All individuals were analyzed regarding these parameters before and after the 10 minute massage of effleurage in the back now. Results: SDNN index increases significantly in the GES after application of massage (p<0,05). HR showed significant lower values in the experimental groups GES and GEP relative to control, whereas DBP increased. Conclusion: The superficial effleurage seems to have a tendency to produce a higher vagal activation.
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Cremer, Antoine. "Déterminants et conséquences de l'hypotension orthostatique en population générale et hypertendue." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0038.
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L’hypotension orthostatique correspond à une baisse de la pression artérielle lors du passage à la position debout. Ce paramètre est associé à un sur-risque d’accident vasculaire cérébral, d’infarctus du myocarde, d’insuffisance cardiaque et de mortalité totale. Il est de ce point de vu proche des marqueurs de variabilité tensionnelle conventionnels que sont la variabilité tensionnelle inter-visite, la variabilité de moyen terme mesurée en auto-mesure tensionnelle et la variabilité de court terme mesurée en holter tensionnel. Cependant, contrairement à ces marqueurs conventionnels, l’association avec la démence n’a pas été démontrée. D’autre part, les relations entre l’hypotension orthostatique et ces autres marqueurs de variabilités ne sont pas connus. Enfin, si le diagnostic de l’hypotension orthostatique est relativement simple, la généralisation du dépistage en consultation n’est pas réalisée faute de temps. Objectifs : Nous proposons dans ce travail de mesurer l’association entre la présence d’une hypotension orthostatique et la survenue d’une démence. Nous réaliserons une étude mécanistique des déterminants de l’hypotension orthostatique à travers ses relations avec deux paramètres particuliers qui sont la variabilité tensionnelle en auto-mesure et la rigidité artérielle. Enfin, nous proposerons une méthode diagnostic par l’usage de l’auto-mesure tensionnelle. Matériel et méthode : Ces travaux sont réalisés à partir de la cohorte des 3 Cités qui est une cohorte de population générale de sujets de plus de 65ans recrutés sur trois centres : Bordeaux, Dijon et Montpellier. Une première étude longitudinale étudiera l’association entre la présence d’une hypotension orthostatique à l’inclusion dans la cohorte et la survenue d’une démence dans le suivi à 12 ans à travers des analyses de survie. Une deuxième étude transversale, utilisera un échantillon des sujets de Dijon autour du suivi à 10 ans qui ont bénéficié à la fois d’un dépistage de l’hypotension orthostatique, de la mesure de la rigidité artérielle et de la réalisation d’une série d’auto-mesure tensionnelle. Enfin, le dernier travail proposera une étude de faisabilité en soins courant de dépistage de l’hypotension orthostatique à travers un protocole d’auto-mesure tensionnelle adapté. Résultats : 7425 sujets ont été suivis sur une période de 12ans. La prévalence de l’hypotension orthostatique était de 13%. Le nombre de cas incidents de démence était de 512 cas. Les analyses de survie ont montré que l’hypotension orthostatique était associée à un sur-risque de démence de l’ordre de 25% dans des modèles ajustés en particulier sur le niveau de pression artérielle. Dans le deuxième travail une analyse transversale chez 1150 sujets a montré que l’hypotension orthostatique était associée de manière indépendante à la fois à la variabilité tensionnelle en autom-esure et à la rigidité artérielle. La variabilité tensionnelle et la rigidité artérielle ne sont pas associés. Dans le troisième travail, plus de 500 séries d’auto-mesure tensionnelle furent réalisées avec mesure de la pression artérielle en position debout sans altérer la qualité de l’auto-mesure tensionnelle classique. Conclusion : L’hypotension orthostatique est un paramètre hémodynamique riche qui reflète à la fois un vieillissement vasculaire marquée et un défaut de régulation de la pression artérielle immédiate. Elle est associée de manière indépendante au risque de démence. Une amélioration du diagnostic est possible par l’auto-mesure tensionnelle qui permet de multiplier les mesures en position debout et qui améliore le taux de dépistageOrthostatic hypotension is a blood pressure drop when moving to standing position. It is associated with an over-risk of stroke, myocardial infarction, heart failure and total mortality. From this point of view, it is close to the conventional markers of blood pressure variability which are the inter-visit blood pressure variability, the mid-term variability measured by home blood pressure and the short-term variability measured by an ambulatory blood pressure monitoring. However, unlike these conventional markers, the association with dementia has not been demonstrated. In addition, the relationships between orthostatic hypotension and these other markers of variability are not known. Finally, although the diagnosis of orthostatic hypotension is relatively simple, the generalization of screening in consultation is not achieved. Objectives: In this work, we propose to measure the association of the orthostatic hypotension and the occurrence of dementia. In addition, we will carry out a mechanistic study of the determinants of orthostatic hypotension through its relations with two particular parameters : mid term variability and arterial stiffness. Finally, we will propose a diagnostic method using home blood pressure measurement. Material and methods: This work is based on the "3 Cities" cohort which is a general population cohort of subjects over 65 years old recruited from three centres: Bordeaux, Dijon and Montpellier. We will first study the association between orthostatic hypotension at baseline cohort and the occurrence of dementia in the 12-year follow-up through survival analyses. A second cross-sectional study will use a sample of Dijon subjects around the 10-year follow-up who were screened for orthostatic hypotension, pulse wave velocity measurement and performed a series of home blood pressure measurement. Finally, the last work will propose a feasibility study on the routine care of screening for orthostatic hypotension using an adapted blood pressure self-measurement protocol. Results: 7425 subjects were followed over a 12-year period. The prevalence of orthostatic hypotension was 13%. The number of incident cases of dementia was 512. Survival analyses showed that orthostatic hypotension was associated with an over-risk of dementia in the order of 25% adjusted with blood pressure level. In the second work, a cross-sectional analysis in 1000 subjects showed that orthostatic hypotension was independently associated with both mid-term blood pressure variability and arterial stiffness. Pressure variability and arterial stiffness were not associated. In the third work, we performed 500 series of home blood pressure with a BP measurement in the standing position without altering the quality of the classical report. Conclusion: Orthostatic hypotension is a rich hemodynamic parameter that reflects both a marked vascular ageing and a defect of immediate blood pressure regulation. It is independently associated with the risk of dementia. An improvement in diagnosis is possible through self-measurement of blood pressure, which allows more measurements to be taken in the standing position and improves the screening rate
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Manarte, Ana Rita Sousa. "Efeitos agudos do Huffing na função cardíaca." Bachelor's thesis, [s.n.], 2014. http://hdl.handle.net/10284/4329.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaObjetivo: Verificar se o Huffing provoca efeitos hemodinâmicos significativos ao nível da frequência cardíaca (FC) e pressão arterial (PA) e na variabilidade da FC (VFC). Metodologia: Uma amostra de 20 participantes, todos alunos da Universidade Fernando Pessoa, foram divididos em 2 grupos: controlo (GC) e experimental (GE). No GC nenhuma técnica foi aplicada, os indivíduos apenas estiveram 15 minutos a respirar a 15 cpm controlados com um metrónomo, em decúbito dorsal sem qualquer inclinação da marquesa. No GE, os 10 indivíduos inicialmente respiram durante 7 minutos com controlo do metrónomo, no minuto seguinte a marquesa foi inclinada a 45º e foram efectuados 3 Huffings. Em seguida a marquesa foi colocada sem inclinação e voltaram a respirar de forma controlada durante 7 minutos. Em ambos os grupos foi medida a PA e analisada a FC média (FCméd) e máxima (FCmáx) Resultados: Verificou-se que todos os índices, excepto LF/HF apresentaram diferenças significativas no momento após a técnica. A PA e FCméd e FCmáx aumentaram significativamente no GE. Conclusões: O Huffing produziu alterações no sistema autónomo, com predomínio da acção sobre o sistema simpático.
Objective: Verify if the Huffing causes significant hemodynamic effects concerning the heart rate (HR) and blood pressure (BP) and the variability of the HR (VHR). Methodology: Twenty students of Fernando Pessoa’s University were divided in 2 groups: a control group (CG) and an experimental group (EG). On the CG no technique was applied, the individuals were breathing only 15 minutes at 15 breaths/minute controlled with a metronome, in supine position without inclination of the marchioness. On the EG, 10 individuals initially breathed 7 minutes with metronome control. Then, in the next minute the marchioness was inclined to 45º and there were made 3 Huffings. After that, the marchioness was laid without inclination and the subjects breathed again in a controlled way during 7 minutes. In both groups was measured the BP and analyzed the medium and maximum HR. Results: It was verified that all indexes, except LF/HF showed significant differences after the technique. The BP and both Heart Rates increased significantly in the experimental group. Conclusions: The Huffing produced alterations on the Autonomous System, with a dominance of the action over the sympathetic system.
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Santos, Wellington Bruno. "Mecanismos de variabilidade de pressão arterial batimento-a-batimento e desempenho cognitivo em idosos." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9145.
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O objetivo deste estudo foi investigar os mecanismos de variabilidade da pressão arterial sistólica batimento-a-batimento através da análise espectral do componente de baixa frequência da variabilidade da pressão arterial sistólica, de medidas de velocidade da onda de pulso e de análise da pressão de incremento em idosos normotensos e hipertensos em tratamento anti-hipertensivo. Adicionalmente, investigamos a associação da variabilidade da pressão arterial com a espessura médio-intimal carotídea. Também investigamos a associação entre variabilidade da pressão arterial batimento-a-batimento e da frequência cardíaca com desempenho cognitivo. A pressão arterial foi medida continuamente através de fotopletismografia em posição supina e semi-ereta passiva. A variabilidade da pressão arterial foi estimada pelo desvio padrão das medidas batimento-a-batimento. Medidas de velocidade de onda de pulso, de pressão de incremento e ultrassonografia das artérias carótidas para medidas da espessura médio-intimal foram realizadas. O componente de baixa frequência da variabilidade da pressão arterial sistólica em posição supina e semi-ereta apresentou uma associação positiva independente coma variabilidade nos modelos de regressão linear múltipla ajustado pela velocidade de onda de pulso ou pela pressão de incremento.O componente de baixa frequência do barorreflexo em posição supina apresentou uma associação negativa independente com a variabilidade da pressão arterial sistólica e nos mesmos modelos. Não foi demonstrada associação entre a variabilidade da pressão arterial sistólica com espessura médio-intimal das artérias carótidas. Não foi demonstrada associação da variabilidade da pressão arterial sistólica batimento-a-batimento ou da frequência cardíaca com desempenho cognitivo global. Foi demonstrada associação positiva e independente do componente de baixa frequência do espectro de variabilidade da pressão arterial e da frequência cardíaca com domínios cognitivos relacionados ao lobo frontal. Em conclusão, a modulação simpática do tono vascular arterial, a função vascular miogênica e a desregulação do barorreflexo correlacionam-se com a variabilidade da pressão arterial batimento-a-batimento, o que não foi observado em relação `a rigidez arterial,pressão de incremento eespessura médio-intimal carotídea. A variabilidade da pressão arterial sistólica e da frequência cardíaca não apresentaram correlação com o desempenho cognitivo global, mas apresentaram associação positiva e independente com escores de função executiva.The objective of this study was to investigate the mechanisms of variability of the systolic beat-to-beat blood pressure in elderly individuals through spectral analysis of low frequency components of systolic blood pressure variability, measures of pulse wave velocity and augmentation pressure analysis. In addition, we investigated the association of blood pressure variability with carotid intima-media thickness. Also, we investigated the association between beat-to-beat blood pressure and heart rate variability with cognitive performance in the sample. Arterial pressures were measured by photoplethysmography in supine position and during passive semi-upright. The spectra of variability of systolic blood pressure values were subsequently analyzed in the laboratory. Measures of pulse wave velocity, the reflected wave (augmentation pressure) and ultrasonography for carotid intima-media thickness measurements were performed. The low frequency component of systolic blood pressure variability in the supine and semi-upright position was an independent positive predictor of variability in multiple linear regression models with pulse wave velocity and with augmentation pressure; the low frequency component of the baroreflex in supine position was a negative predictor of variability in the same models. It was not demonstrated association of systolic blood pressure variability with intima-media thickness. It was not demonstrated association of beat-to-beat systolic blood pressure variability or heart rate with global cognitive performance in elderly apparently healthy in regular treatment of hypertension. It was demonstrated a positive and independente association of the low-frequency component of the spectrum of blood pressure and heart rate of variability with cognitive domains related to the frontal lobe (matrix reasoning and executive function score). In conclusion, sympathetic modulation of vascular tone, arterial vascular myogenic function, and baroreflex deregulation are predictors of beat-to-beat systolic blood pressure variability, unlike arterial stiffness and augmentation pressure. While blood pressure variability shows no association with carotid intima-media thickness or global cognitive performance in apparently healthy normotensive and hypertensive elderly under anti-hypertensive treatment. The heart rate variability showed no correlation with global cognitive performance in this age group, but presented positive and independent association with executive function score. Sympathetic modulation of arterial vascular tone and myogenic function also exhibited positive and independent association with matrix reasoning.
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Prado, Renata Martins da Silva. "Análise da variabilidade da frequência cardíaca (VFC) em cirurgias de exodontia de terceiros molares inferiores." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/23/23147/tde-11092014-150554/.
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Embora amplamente utilizados no monitoramento durante o tratamento odontológico, pesquisas questionam a sensibilidade de medidas como da Pressão Arterial e Frequência Cardíaca na detecção precoce de anormalidades cardiocirculatórias iniciais e, sobretudo, das respostas autonômicas ao estresse mental e às drogas administradas durante procedimentos cirúrgicos. A Variabilidade da Frequência Cardíaca (VFC), isto é, a variação do intervalo RR batimento-a-batimento, é reconhecida como uma sensível preditora de eventos cardiovasculares graves como arritmias, isquemia miocárdica e morte súbita, além de trazer informações sobre a atividade do sistema nervoso autônomo. O objetivo deste estudo foi avaliar a aplicabilidade da análise da VFC (obtida a partir da utilização de frequencímetro portátil) na mensuração de respostas fisiológicas durante cirurgias odontológicas. 33 pacientes, ASA 1, com indicação de extração de terceiros molares inferiores foram avaliados em 3 momentos: entrevista, cirurgia e pós-operatório, com intervalos de uma semana. Também foi avaliada a ansiedade ao tratamento odontológico e relato de evento traumático prévio. A VFC foi obtida após processamento dos intervalos RR registrados com o frequencímetro Polar RS800. Foram analisadas as variáveis do domínio tempo (SDNN e rMSSD) e frequência (razão LF/HF). Concomitantemente foram medidas Pressão Arterial Sistólica (PAS), Diastólica (PAD), Média (PAM), Frequência Cardíaca (FC) e variáveis eletrocardiográficas. Nesta amostra de voluntários saudáveis, a ansiedade ao tratamento odontológico e o antecedente de experiências traumáticas não se mostraram correlacionados à maior intensidade de dor pós-operatória. Não foram observadas alterações da PAS, PAD, PAM, FC, tampouco alterações eletrocardiográficas relevantes ao longo das fases cirúrgicas. Com relação à VFC, houve redução do SDNN entre a fase basal e a fase anestesia. Gênero, idade, ansiedade e tabagismo passivo não determinaram comportamentos diferentes nas variáveis estudadas. O presente estudo demonstrou viabilidade da inclusão do estudo da VFC em protocolos clínicos de avaliação do comportamento do aparelho cardiovascular em procedimentos odontológicos. O estudo da VFC através de frequencímetros de pulso, instrumentos de baixo custo, ampla disponibilidade e fácil manuseio, pode prestar-se como uma ferramenta útil em estudos de segurança cardiovascular de novos fármacos e procedimentos.Although widely used in monitoring during dental treatment, researches question the sensitivity measures such as Blood Pressure and Heart Rate (HR) in the early detection of cardiovascular abnormalities early and especially of autonomic responses to mental stress and drugs administered during surgical procedures. The Heart Rate Variability (HRV), the variation of the RR interval beat-to-beat, is recognized as a significant predictor of serious cardiovascular events such as arrhythmias, myocardial ischemia and sudden death, in addition to providing information about the activity of autonomic nervous system. The aim of this study was to evaluate the applicability of HRV analysis (obtained from the use of portable frequency meter) in measuring physiological responses during dental surgery. 33 patients, ASA 1, indicating the extraction of third molars were evaluated in three stages: interview, surgery and postoperatively at intervals of a week. Was also assessed anxiety during dental treatment and reported prior traumatic event. HRV was obtained after processing of RR intervals recorded with the frequency meter Polar RS800. The variables analyzed were in the time domain (SDNN and rMSSD) and frequency (LF / HF ratio). Concomitantly were measured systolic blood pressure (SBP), diastolic (DBP), Medium (PAM), HR and electrocardiographic variables. In this sample of healthy volunteers, anxiety during dental treatment and previous traumatic experiences were not correlated to the intensity of postoperative pain. No changes were observed in SBP, DBP, MAP, HR, nor relevant electrocardiographic changes along the surgical stages. Regarding to HRV, the SDNN decreased between the baseline phase and phase anesthesia. Gender, age, anxiety, and passive smoking didnt determine different behaviors in studied variables. The present study demonstrated feasibility of including the study of HRV in clinical protocols for assessing the behavior of the cardiovascular system in dental procedures. The study of HRV by pulse frequency meters, instruments low cost, wide availability and easy handling, it may lend itself as a useful tool in studies of cardiovascular safety of new drugs and procedures.
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Buto, Marcele Stephanie de Souza. "Análise da variabilidade da frequência cardíaca e da pressão arterial sistólica na síndrome da fragilidade." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/5339.
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Previous issue date: 2015-02-05Universidade Federal de Minas Gerais
Frailty is related to a decrease in the physiological reserves that causes a difficult to maintain homeostasis. The analysis of heart period (HP) and blood pressure (BP) variabilities can contribute to the understanding of cardiovascular homeostasis in the frailty syndrome. Objective: To compare HP and BP variabilities in frail, prefrail and nonfrail, un supine and orthostatic positions, by univariate and bivariate analysis. Methods: 39 elderly were evaluated and distributed in frail, prefrail and nonfrail groups, accordingly to frailty phenotype. The RR interval (RRi) and the systolic BP (SBP) series were registered for 15 minutes in the supine position and 15 minutes in orthostatic position. Univariate analysis (RRi: mean, variance, LFnu, HFabs and LF/HF and the SBP: mean, variance and LFabs) and bivariate analysis (phase, gain (α) and coherence (K2)) were performed. A two-way repeated measures ANOVA test was used for the statistical analysis; a 5% significance level was considered, along with group, position and interaction effects. Results: Univariate analysis do not detected changes in frailty syndrome. However, in the bivariate analysis frail presented lower K² than nonfrail in orthostatic position. Prefrail and frail reported a significant decrease in K² values in orthostatic position in comparison to the supine. Conclusion: Univariate analysis of HP and BP variabilities do not change when frailty syndrome is present. However, bivariate analysis indicated decoupling between HP and BP in frailty presence. Thus, a reduced K2 might be a marker of frailty process.
A fragilidade está associada à redução das reservas fisiológicas que leva à dificuldade na manutenção da homeostase. A análise da variabilidade da frequência cardíaca (FC) e da pressão arterial (PA) pode contribuir para a compreensão da homeostase cardiovascular na síndrome da fragilidade. Objetivo: Comparar a variabilidade da frequência cardíaca (VFC) e a variabilidade da pressão arterial sistólica (VPA) de indivíduos frágeis, pré-frágeis e robustos, nas posturas supina e ortostática, utilizando-se de análises univariada e bivariada. Métodos: Foram avaliados 39 idosos, alocados em 3 grupos de acordo com o fenótipo da fragilidade. As séries de intervalos RR (iRR) e de PA sistólica (PAS) foram registradas por 15 minutos em repouso na posição supina, e 15 minutos na posição ortostática. Foram realizadas as análises univariada (iRR: média, variância, baixa frequência em unidades normalizadas (BFun), alta frequência em unidades absolutas (AFabs) e razão entre a baixa e alta frequência (BF/AF) e PAS: média, variância e BFabs) e bivariada (fase, ganho (α) e coerência (K2)). Para análise estatística foi utilizado o teste Anova two way de medidas repetidas, com efeitos de grupo, posição e interação entre estes, considerando um nível de significância de 5%. Resultados: A análise univariada não detectou alterações na síndrome da fragilidade. Entretanto, na análise bivariada os frágeis apresentaram menores valores de K2 em comparação aos robustos na posição ortostática. Préfrágeis e frágeis apresentaram redução significativa nos valores de K2 na posição ortostática em comparação à supina. Conclusão: A variabilidade da FC e da PA, avaliada pela análise univariada, não se altera quando a fragilidade está presente. Por sua vez, a análise bivariada indicou um maior desacoplamento entre FC e PA na presença da síndrome da fragilidade. Desta forma, a K2 reduzida pode ser um marcador do processo de fragilização.
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Fontolliet, Thimothée. "Régulations cardiovasculaires au repos et à l’exercice chez l’Homme : nouvelles perspectives de la variabilité de fréquence cardiaque et de la sensibilité du baroréflexe en boucle ouverte." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSES007/document.
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Le système nerveux autonome (SNA) contribue de façon importante aux régulations des fonctions cardiovasculaires. Pendant des décennies, les chercheurs ont essayé de comprendre comment la variabilité de la fréquence cardiaque (VFC) et le gain du baroréflexe cardiaque pouvaient être utilisés comme marqueurs significatifs du contrôle neurovégétatif cardiaque, et parfois de son altération. L'objectif général de cette thèse est de mieux comprendre le rôle du SNA dans la modulation et les adaptations des fonctions cardiaques et vasculaires. Le projet comprenait quatre études.Dans la première étude, nous avons analysé les effets de l'accélération gravitationnelle graduées sur la régulation neurovégétative de la fréquence cardiaque et de la vasomotricité artériolaire. Dans ces expositions expérimentales des variables cardiovasculaires et respiratoires ont été modifiées de façon spécifique. Nos résultats ne sont pas compatibles avec la mise en jeu d’une régulation sympathique au niveau cardiaque en situation d’hypergravité brève. Nous avons supposé que seule la branche sympathique du SNA était active durant une exposition à une accélération de gravité élevée. La réponse adaptative de la vasomotricité artérielle vasculaire est observée en condition de grande décharge des barorécepteurs. Notre deuxième travail eu pour objet l'effet de la dénervation pulmonaire sur la VFC, et a donc été conduit chez des patients ayant subi une greffe pulmonaire complète. Le greffon n'étant plus relié au SNA, il s'agit d'un excellent modèle expérimental pour l'étude de la régulation cardiovasculaire en l’absence de modulation de l'activité cardiaque par des afférences nerveuses pulmonaires parasympathiques et/ou sympathiques. Puisque la VFC dans les hautes fréquences est reconnue comme largement déterminée par le profil ventilatoire, on s’attend à ce que la composante à haute fréquence de la VFC soit absente chez les sujets transplantés bi-pulmonaires. Les résultats montrent que cette dénervation pulmonaire implique une forte réduction de la VFC totale et dans les deux bandes de fréquence étudiées, hautes et basses. Cela indique donc qu’une large contribution de la modulation nerveuse de la VFC répond aux afférences pulmonaires. La sensibilité du baroréflexe est réduite. Le rapport plus élevé entre les basses et les hautes fréquences traduit une réduction de puissance totale principalement due à la diminution de la composante haute fréquence. Ces résultats montrent que les afférences pulmonaires contribuent largement à la à la modulation neurovégétative de la composante à hautes fréquences de la VFC. La variabilité de la pression artérielle est beaucoup moins modifiée que celle de la VFC par la transplantation bipulmonaire, ce qui met en évidence que les afférences pulmonaires contribuent spécifiquement à la modulation de la VFC. Cette observation est un argument fort pour reconnaître des voies de régulation différentes pour les variabilités de fréquence cardiaque d’une part et de pression artérielle d’autre part. Le troisième article traite des effets sur la modulation cardiovasculaire de blocages pharmacologiques du SNA sur les régulations de fréquence cardiaque et de vasomotricité périphérique, au repos et pendant l'exerciceAutonomic nervous system (ANS) and cardiovascular regulation are closely linked. For decades, researches have tried to understand how heart rate variability (HRV) and baroreflexes can be used as significant markers of the autonomic nervous control, and sometimes of its impairments. The general aim of this thesis is to gain further insights into the role of ANS in modulating cardiac and vascular functions. The project consisted of four studies.In the first study, we analysed the effects of gravitational acceleration on cardiovascular autonomic control. This special condition showed interesting results for cardiorespiratory variables. Our results did not agree with the notion of sympathetic up-regulation in hypergravity. We speculated that only the sympathetic branch of the ANS might have been active during elevated gravitational acceleration exposure. Furthermore, the vascular response occurred in a condition of massive baroreceptor unloading.Our second work targeted the effect of lung denervation on HRV in bilateral lung transplant recipients. As the graft is no longer connected to the ANS, this is an excellent experimental model for the study of cardiovascular regulation without modulation of heart activity by parasympathetic and/or sympathetic lung afferents. The hypothesis was that the modulation of the high frequency component of HRV by the breathing frequency is mediated by the ANS. This hypothesis would be supported by the results if the high frequency component of HRV is suppressed in bilateral lung transplant recipients. Lung denervation implied strong HRV reduction, all indices being decreased, indicating that neural modulation from lung afferents contributes largely to HRV. Baroreflex sensitivity was reduced. The higher low-versus-high frequency ratio implied that the total power drop was mostly due to the high frequency component, indicating that neural modulation from lung afferents largely contributes to the high frequency component of HRV. The changes in blood pressure variability were smaller than those in HRV, suggesting that the effects of lung denervation were specific to HRV modulation. This finding confirms that blood pressure variability and HRV are under different control mechanisms.The third article concerns the effects of autonomic blockades on cardiovascular modulation, at rest and during exercise. We hypothesized that HRV should decrease with vagal or sympathetic blockades, and disappear during simultaneous blockade of both ANS branches. The results suggest that the parasympathetic outflow to the heart is the main determinant of HRV, while the role of the sympathetic branch is less important. Indeed, sympathetic blockades failed in changing HRV indices at rest, indicating that a selective blockade of cardiac ß-adrenergic receptors has no effects on spontaneous heart rate oscillations. These effects are specific to HRV, as the effects observed on blood pressure variability are indirectly related to the action of the administered drugs. The changes in baroreflex sensitivity were consistent with the changes in arterial blood pressure variability, suggesting that baroreflexes may modulate the LF power of arterial blood pressure
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Palasí, Franco Antonio. "Variabilidad de la presión arterial como factor asociado a deterioro cognitivo y atrofia cerebral." Doctoral thesis, Universitat Autònoma de Barcelona, 2021. http://hdl.handle.net/10803/672589.
Full textAbstract:
La hipertensió arterial és un factor de risc de deteriorament cognitiu (DC). Tradicionalment, aquest risc s’ha atribuït a les xifres mitjanes de pressió arterial (PA). No obstant, la PA està sotmesa a una gran variabilitat que pot ser estudiada a curt plaç (en 24 hores) mitjançant la monitorització ambulatòria de la pressió arterial (MAPA) o a llarg plaç amb les PA de diferents visites separades en el temps. Recentment, la variabilidad de la PA (VPA) s’ha associat, independentment de les xifres mitjanes de PA, a un major risc de DC i d’atròfia cerebral. Per determinar la VPA existeixen diferents índexs, com la desviació estàndard (DS), el coeficient de variació (CV) i l’ Average Real Variability (ARV).
Mentre que la relació entre la VPA a llarg plaç i el DC està ben establerta, els estudis sobre VPA a curt plaç i cognició mostren resultats discordants. A més, l’associació entre ambdós tipus de VPA i el deteriorament cognitiu lleu (DCL), estat cognitiu que precedeix a la demència, ha estat poc estudiada i no s’ha fet de forma prospectiva.
L’objectiu d’aquesta tesi és estudiar la VPA a curt i llarg plaç en una cohort de pacients hipertensos i determinar prospectivament la seva associació amb el decliu cognitiu i amb les transicions entre els estats de normalitat cognitiva i DCL després de quatre anys de seguiment. També s’investiga l’associació de la VPA amb el grau d’atròfia cerebral temporal medial (ATM) a la RMN cranial.
Es van avaluar 361 pacients hipertensos mitjançant dues visites separades quatre anys. A cada visita es va realitzar una avaluació cognitiva, una RMN cranial i una MAPA (utilitzada per a calcular la VPA a curt plaç). Es recolliren, també, les determinacions de PA realitzades en Atenció Primària entre ambdues visites per calcular la VPA a llarg plaç. A cada visita es va passar la Rating Scale-second edition (DRS-2) i cada subjecte es va clasificar en normalitat cognitiva o DCL. Entre ambdues visites es recolliren els casos de DCL incident. L’ATM va ser avaluada mitjançant l’escala visual de Scheltens.
Per la VPA a llarg plaç, elevacions de la DS (OR 1.14,IC 95%:1.01-1.29), del CV (OR 1.19,IC 95%:1.02-1.40) i de l’ARV (OR 1.11,IC 95%:1.01-1.22) de la PA sistòlica s’associaren a un major risc de DCL incident independentment de les xifres de PA acumulada. Les puntuacions Z de la DRS-2 als quatre anys es relacionaren negativament amb el CV (B -0.03,IC 95% -0.06 a -0.01) i l’ARV de la PA sistòlica (B -0.02,IC 95% -0.04 a -0.02). La subescala de funció executiva de la DRS-2 es va relacionar amb la DS de la PA sistòlica (B -0.02,IC 95% -0.04 a 0.00). L’ATM es va associar als quartils superiors de la DS (OR 2.13,IC 95%:1.01-4.48) i del CV de la PA sistòlica (OR 2.35,IC 95%:1.14-4.82).
La VPA a curt plaç no es va associar amb el risc de desenvolupar DCL incident Únicament es va detectar una associació positiva per l’ARV de la PA sistòlica diürna amb les puntuacions totals de la DRS-2 mesurada quatre anys després (B 0.05,IC 95%:0.03-0.09). No s’observaren associacions entre l’ATM i la VPA a curt plaç.
En conclusió, diferents índexs de VPA a llarg plaç s’associaren al risc de DCL incident, al decliu de les puntuacions en la DRS-2 i a la presència d’ATM, independentment dels nivells de PA. Aquestes associacions no es van trobar per la VPA a curt plaç. La VPA a llarg plaç podria tenir utilitat com a predictor de DCL incident i decliu cognitiu i trobar-se associada al grau d’ATM.La hipertensión arterial es un factor de riesgo para el deterioro cognitivo (DC). Tradicionalmente, este riesgo se ha atribuido a las cifras medias de presión arterial (PA). Sin embargo, la PA está sujeta a una gran variabilidad que puede ser estudiada a corto plazo (en 24 horas) mediante la monitorización ambulatoria de la presión arterial (MAPA) o a largo plazo con las PA de diferentes visitas separadas en el tiempo. Recientemente la variabilidad de la PA (VPA) se ha asociado, independientemente de las cifras medias de PA, a un mayor riesgo de DC y de atrofia cerebral. Para determinar la VPA existen diferentes índices, como la desviación estándar (DS), el coeficiente de variación (CV) y la Average Real Variability (ARV). Mientras que la relación entre la VPA a largo plazo y el DC está bien establecida, los estudios sobre VPA a corto plazo y cognición muestran resultados discordantes. Además, la asociación entre ambos tipos de VPA y el deterioro cognitivo leve (DCL), estado cognitivo que precede a la demencia, ha sido poco estudiada y no se ha hecho de forma prospectiva. El objetivo de esta tesis es estudiar la VPA a corto y largo plazo en una cohorte de pacientes hipertensos y determinar prospectivamente su asociación con el declive cognitivo y con las transiciones entre los estados de normalidad cognitiva y DCL tras cuatro años de seguimiento. También se investiga la asociación de la VPA con el grado de atrofia cerebral temporal medial (ATM) en la RMN craneal. Se evaluaron 361 pacientes hipertensos mediante dos visitas separadas cuatro años. En cada visita se realizó una evaluación cognitiva, una RMN craneal y una MAPA (usada para calcular la VPA a corto plazo). Se recogieron también las determinaciones de PA que se realizaron en Atención Primaria entre ambas visitas para calcular la VPA a largo plazo. En cada visita se pasó la Dementia Rating Scale-second edition (DRS-2) y cada sujeto fue clasificado en normalidad cognitiva o DCL. Entre ambas visitas se recogieron los casos de DCL incidente. La ATM fue evaluada mediante la escala visual de Scheltens. Para la VPA a largo plazo, elevaciones de la DS (OR 1.14,IC 95%:1.01-1.29), del CV (OR 1.19,IC 95%:1.02-1.40) y de la ARV (OR 1.11,IC 95%:1.01-1.22) de la PA sistólica se asociaron a mayor riesgo de DCL incidente independientemente de las cifras de PA acumulada. Las puntuaciones Z de la DRS-2 a los cuatro años se relacionaron negativamente con el CV (B -0.03,IC 95% -0.06 a -0.01) y la ARV de la PA sistólica (B -0.02,IC 95% -0.04 a -0.02). La subescala de función ejecutiva de la DRS-2 se relacionó con la DS de la PA sistólica (B -0.02,IC 95% -0.04 a 0.00). La ATM se asoció a los cuartiles superiores de la DS (OR 2.13,IC 95%:1.01-4.48) y del CV de la PA sistólica (OR 2.35,IC 95%:1.14-4.82). La VPA a corto plazo no se asoció con el riesgo de desarrollar DCL incidente. Únicamente se detectó una asociación positiva para la ARV de la PA sistólica diurna con las puntuaciones totales de la DRS-2 medida cuatro años después (B 0.05,IC 95%:0.03-0.09). No se observaron asociaciones entre la ATM y la VPA a corto plazo. En conclusión, varios índices de VPA a largo plazo se asociaron al riesgo de DCL incidente, al declive de las puntuaciones en la DRS-2 y a la presencia de ATM, independientemente de los niveles de PA. Estas asociaciones no se encontraron para la VPA a corto plazo. La VPA a largo podría tener utilidad como predictor de DCL incidente y declinar cognitivo y encontrarse asociada al grado de ATM.
Hypertension is a risk factor for cognitive impairment (CI). Traditionally, this risk has been attributed to mean blood pressure (BP). However, BP blood pressure levels exhibit a great variability over time. Blood pressure variability (BPV) can be assessed in the short term (within 24 hours) using ambulatory blood pressure monitoring (ABPM) or in the long term through BP measurements blood pressure measurements from different visits separated in time. Recently, BPV has been associated with a higher risk of CI and cerebral atrophy, regardless of the mean arterial pressure levels. Several indices have been proposed to measure BPV, such as the standard deviation (SD), the coefficient of variation (CV) and the Average Real Variability (ARV). The relationship between long-term BPV and CI is well established; however, studies assessing short-term BPV and cognition show conflicting results. Furthermore, the association between both types of VPA and mild cognitive impairment (MCI), a cognitive state that precedes dementia, has been assessed in few studies and has not been performed prospectively. The aim of this Thesis was to evaluate short-term and long-term BPV in a cohort of hypertensive patients and prospectively determine its association with cognitive decline and with cognitive changes between normal cognition states and MCI after four years of follow-up. The association of BPV with medial temporal cerebral atrophy (MTA) on cranial MRI was also investigated. 361 hypertensive patients were evaluated in two visits separated four years between them. A cognitive assessment, cranial MRI, and ABPM (used to calculate short-term VPA) were performed at each visit. BP determinations measured in Primary Care between both visits were also collected to calculate long-term BPV. In both visits, the Dementia Rating Scale-second edition (DRS-2) was performed and each subject was classified in cognitive normal state or MCI. Incident MCI patients between both visits were collected. The MTA was evaluated using the visual Scheltens scale. For long-term BPV, elevations of SD (OR 1.14,IC 95%:1.01-1.29), CV CV (OR 1.19,IC 95%:1.02-1.40) and ARV (OR 1.11,IC 95%:1.01-1.22) of systolic BP exhibited a higher risk of incident MCI, independent of the cumulative BP values. The DRS-2 scale Z score was negatively related to systolic CV (B -0.03,IC 95% -0.06 a -0.01) and ARV (B -0.03,IC 95% -0.06 a -0.01). The executive function subscale was also associated with systolic SD (B -0.02,IC 95% -0.04 a 0.00). MTA was associated with higher quartiles of the systolic SD (OR 2.13,IC 95%:1.01-4.48) and CV (OR 2.35,IC 95%:1.14-4.82). Short-term BPV was not related to a higher risk of MCI. A positive association between daytime systolic ARV and DRS-2 total Z scores was detected (B 0.05, IC 95%:0.03-0.09). There were no associations between short-term BPV and MTA. In conclusion, several indices of long-term BPV were associated with the risk of incident MCI, with decreased DRS-2 scores and with the presence of brain MTA, regardless of blood pressure levels. On the other hand, these associations were not found for short-term BPV. In this way, long-term BPV could be useful as a possible predictor of MCI and cognitive decline and could be associated with MTA.
Universitat Autònoma de Barcelona. Programa de Doctorat en Medicina
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Souza, Silvia Beatriz Paulino Cavasin de. "Associação da disfunção diastólica de origem hipertensiva com a atividade simpática cardíaca e periférica." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-01122011-103904/.
Full textAbstract:
INTRODUÇÂO: A hipertensão arterial sistêmica (HAS) é uma condição clínica com alta prevalência, sendo considerada como o principal fator de risco modificável para o desenvolvimento de insuficiência cardíaca (IC). Dentre os mecanismos relacionados à progressão da HAS para a IC, a hiperatividade simpática e a disfunção endotelial devem ser consideradas. OBJETIVO: Avaliar a modulação do sistema nervoso autônomo (central e periférico), e a função endotelial em pacientes hipertensos com diferentes graus de disfunção diastólica (DD) do ventrículo esquerdo (VE). CASUÍSTICA E MÉTODO: Quarenta e cinco pacientes com HAS, sem outras co-morbidades foram submetidos ao exame de ecoDopplercardiograma tecidual, e foram alocados em três grupos: (GHT) sem alteração funcional ou estrutural cardíacas (n=15, 7 homens, 48±2 anos, IMC 28±1 Kg/m2), (GDD-ar) com diagnóstico prévio de IC diastólica e com DD padrão alteração de relaxamento do VE (n=15, 7 homens, 53±2 anos, IMC 29±1 Kg/m2) e (GDD-pr) com diagnóstico prévio de IC diastólica com padrão pseudonormal ou restritivo de DD do VE (n=15, 9 homens, 51±2 anos, IMC 27±1 Kg/m2). Voluntários saudáveis normotensos (n=14, grupo GNT) pareados para idade, sexo e IMC também foram avaliados. Curvas de pressão arterial (PA) foram registradas de modo contínuo e não invasivo (Finometer®) durante 15 minutos em repouso, na posição supina. Simultaneamente, a atividade nervosa simpática muscular (ANSM) foi registrada por meio da técnica de microneurografia. A variabilidade da freqüência cardíaca (VFC) e da pressão arterial sistólica (VPAS) foi estimada pelo método FFT. Em um segundo momento foi realizada a avaliação da função endotelial, por meio de ultrassonografia da artéria braquial associada à manobra de hiperemia reativa e após administração de trinitrato sublingual. As análises estatísticas foram realizadas pelo teste exato de Fisher e ANOVA, os resultados expressos em média ± erro padrão ou em mediana (valores mínimos e máximos). RESULTADOS: Não houve diferenças de gênero, idade e IMC entre os grupos, como também no uso das diferentes classes de drogas anti-hipertensivas entre os hipertensos. Os parâmetros estruturais cardíacos foram semelhante entre os grupos, com exceção da massa de VE do grupo GDD-pr [98 (66-162) g/m2] foi maior, p<0,05, quando comparada ao grupo GNT [85 (56-95) g/m2]. A PA sistólica (PAS) não foi diferente entre GHT, GDD-ar e GDD-pr [(138 (110-149), 133 (104-190) e 148 (118-171) mmHg, respectivamente]. Os grupos GDD-ar e GDD-pr apresentaram PAS maiores, p<0,05,quando comparados ao grupo GNT [121(108-133) mmHg]. A PA diastólica foi semelhante entre os grupos. Os grupos mostraram semelhantes valores para a modulação autonômica cardíaca avaliada pela VFC. A modulação simpática periférica representada pelo componente LF PAS da VPAS (mmHg2) foi aumentada nos grupos GDD-ar (12,2±1,3) e GDD-pr (11,7±1,2) quando comparados ao grupo GNT (6,7±0,6), p<0,05, mas não quando comparada ao grupo GHT (9,3±1,1). O prejuízo baroreflexo (índice alfa LF, ms/mmHg) foi observado nos grupos GDD-ar (4,6±0,6) e GDD-pr (5,07±0,7) quando comparados ao grupo GNT (8,2±1), p<0,05, mas não quando comparados ao grupo GHT (6,05±0,5). ANSM (espículas/min) foi maior significativamente nos grupos GDD-ar (33±1) e GDD-pr (32±1) quando comparada aos grupos GHT (26±1) e GNT (15±1) p<0,05. Ainda, o grupo GHT apresentou aumento da ANSM quando comparado ao grupo GNT, p<0,05. Os grupo GDD-ar e GDD-pr apresentaram valores semelhantes de ANSM. Com relação à avaliação da função endotelial, os grupos hipertensos apresentaram menor dilatação dependente do endotélio, sendo que somente no grupo GDD-ar [0,67 (0,0-8,7)%] houve significância estatística quando comparado ao GNT [6,3 (2,6-8,2)%]. Na avaliação da vasodilatação independente do endotélio os grupos apresentaram respostas semelhantes. CONCLUSÃO: A presença de disfunção diastólica, em qualquer grau, está associada à maior ANSM e modulação simpática periférica (LF PAS) e a menor sensibilidade do baroreflexo. A modulação simpática cardíaca não apresentou diferença entre os grupos em repouso. Outros estudos são necessários para esclarecer a relação entre causa - efeito de tais achadosINTRODUTION: The hypertension (HP) is a clinical condition with high prevalence, considered as a main modifiable risk factor for developing heart failure (HF). Among the mechanism related to the progression for HP to the HF, the sympathetic hyperactivity and endothelial dysfunction should be considered. OBJECTIVE: Evaluate the autonomic nervous system modulation (central and peripheral), and endothelial function in hypertensive patients with different pattern of diastolic dysfunction (DD) of the left ventricle (LV). METHOD: Forty-five hypertensive patients without comorbities were submitted to tissue Doppler echocardiography and allocated into three groups: (GHT) without cardiac functional or structural abnormalities (n=15, 7 men, 48±2 years, BMI 28±1 Kg/m2); (GDD-ar) with prior diastolic HF and impaired relaxation pattern of DD of LV (n=15, 7 men, 53±2 years, BMI 29±1 Kg/m2), and (GDD-pr) with prior diastolic HF and pseudonormal and restrictive patterns of DD of LV (n=15, 9 men, 51±2 years, BMI 27±1 Kg/m2). Normotensive healthy volunteers matched for age, sex and body mass index were also evaluated. Curves of blood pressure (BP) were recorded non-invasively and continuously (Finometer®) for 15 minutes at rest in the supine position. Simultaneously, muscle nerve sympathetic activity (MNSA) was recorded by microneurography technique. The heart rate and systolic blood pressure variability (HRV and SPBV) was estimated by FFT method. Afterwards, an evaluation of endothelial function through brachial artery ultrasound maneuver associated with reactive hyperemia and after sublingual administration of trinitrate was conducted. Statistical analysis was performed by Fishers exact test and ANOVA, the results are expressed as mean±standard deviation or median (minimum and maximum values). RESULTS: There were no differences in gender, age and BMI between the groups, as well as in the use of different classes of antihypertensive drugs among hypertensive patients. Cardiac structural parameters were similar between groups, except for LV mass in GDD-pr group [98 (66-162) g/m2] which was higher, p<0.05, when compared to the GNT group [85 (56-95) g/m2]. The systolic blood pressure (SBP) was similar between GHT, GDD-ar and GDD-pr groups [(138 (110-149), 133 (104-190) e 148 (118-171) mmHg, respectively]. The GDD-ar and GDD-pr groups had higher SBP, p<0.05, when compared to GNT group [121(108-133) mmHg]. The diastolic BP was similar between groups. The groups showed similar values for cardiac autonomic modulation assessed by HRV. The peripheral sympathetic modulation represented by the LF component of SBP (SBPV, mmHg2) was increased in GDD-ar group (12,2±1,3) and GDD-pr group (11,7±1,2) compared to the GNT group (6,7±0,6), p<0.05, but not when compared to GHT group (9,3±1,1). The impairment of the baroreflex (LF alpha índex, ms/mmHg) was observed in the GDD-ar (4,6±0,6) e GDD-pr (5,07±0,7) groups compared to the GNT group (8,2±1), p<0.05, but not when compared to GHT group (6,05±0,5). MNSA (burst/min) was significantly higher in GDD-ar (33±1) e GDD-pr (32±1) groups compared to GHT group (26±1) and GNT group (15±1) p<0.05. Also the GHT group showed increased MNSA when compared to GNT group, p<0.05. The GDD-ar and GDD-pr groups showed similar values of MNSA. Regarding the assessment of endothelial function, hypertensive groups had lower endothelium-dependent dilatation, but only in GDD-ar group [0,67 (0,0-8,7)%] was statistically significant when compared to GNT group [6,3 (2,6-8,2)%]. In the evaluation of endothelium-independent vasodilatation all groups showed similar responses. CONCLUSION: The presence of diastolic dysfunction of any pattern is associated with higher MNSA and peripheral sympathetic modulation (LF SBP) and lower sensitivity of the baroreflex. Cardiac sympathetic modulation did not differ between groups at rest. Further studies are needed to clarify the relationship between cause-effect of such findings
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Facioli, Tábata de Paula. "Estudo da relação da aptidão cardiorrespiratória com parâmetros hemodinâmicos e autonômicos cardiovasculares em indivíduos saudáveis - comparação entre os sexos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17152/tde-06062017-165114/.
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Foi investigado os efeitos de diferentes níveis de condicionamento físico e a diferença de resposta entre os gêneros sobre a modulação autonômica da variabilidade da frequência cardíaca (VFC), variabilidade da pressão arterial (VPAS) e sensibilidade barorreflexa (SBR). Cento e vinte voluntários saudáveis, com idade entre 18 e 45 anos (60 homens e 60 mulheres) foram submetidos ao teste ergoespirométrico e divididos em três grupos, de acordo com a resposta do VO2pico; grupo de baixa performance (BP= VO2: 22-38 ml kg-1 min-1, n=20 homens e n=20 mulheres), grupo de média performance (MP= VO2: 38-48 ml kg-1 min-1, n=20 homens e n=20 mulheres) e grupo de alta performance (AP= VO2: > 48 ml kg-1 min-1, n=20 homens e n=20 mulheres). O protocolo experimental empregado para avaliação da VFC foi a análise espectral e simbólica e da VPAS foi a análise espectral, ambos das séries dos intervalos R-R, derivados do registro do eletrocardiograma. Já a SBR foi avaliada no domínio do tempo por meio do método da sequência. Todos os registros ocorreram em três momentos distintos: durante o repouso na posição supina (basal), durante o teste de inclinação (tilt test) e durante a recuperação pós teste de esforço máximo. Os resultados sugerem que os homens apresentaram um balanço modulatório autonômico cardíaco da VFC mais favorável às oscilações de LF e índices 0V, enquanto que nas mulheres as oscilações de HF e índices 2LV, 2UV e 2V são mais determinantes, caracterizando uma atuação maior da atividade simpática nos homens e parassimpática nas mulheres. Também, na VPAS as respostas autonômicas são diferentes entre homens e mulheres, onde o sexo masculino apresentou maiores oscilações de LF e o sexo feminino maiores oscilações de HF. Ambos resultados, VFC e VPAS, foi independete do nível de condicionamento físico e do momento analisado (basal, ortostatismo, recuperação). Diferentemente, homens e mulheres parecem possuir atividade barorreflexa semelhantes quando em repouso ou na posição ortostática, porém, após o teste de esforço máximo, mulheres apresentaram maior SBR em relação aos homens.We investigated the effects of different fitness levels and the difference in response between genders on the autonomic modulation of heart rate variability (HRV), blood pressure variability (VPAS) and baroreflex sensitivity (BRS). One hundred and twenty healthy volunteers, aged between 18 and 45 years (60 men and 60 women) underwent cardiopulmonary exercise test and divided into three groups, according to the response of VO2peak; group low performance (LP= VO2: 22-38 ml kg-1 min-1, n=20 men and n=20 women), mean performance (MP= VO2: 38-48 ml kg-1 min-1, n=20 men and n=20 women) and high performance (HP= VO2: > 48 ml kg-1 min-1, n=20 men and n=20 women). The experimental protocol used to evaluate the HRV was the spectral analysis and the symbolic analysis and to evaluate the VPAS was spectral analysis, both of the R-R interval time series from the record the electrocardiogram . The SBR was evaluated in the time domain by the following method. All evaluation occurred in three distinct stages: at rest in the supine position (baseline), during the tilt test (tilt test) and during post maximal exercise test in the recovery. The results showed that men had a heart autonomic modulatory balance of more favorable HRV to LF fluctuations and indices 0V, while in women the oscillations of HF and indexes 2LV, 2UV and 2V are more decisive, featuring higher sympathetic activity in men and in women parasympathetic. Also, in VPAS autonomic responses are different between men and women, where men had greater oscillations of LF and women had greater oscillations of HF. Both results, HRV and VPAS was independete the fitness level and the analyzed time (baseline, orthostatic, recovery). In contrast, men and women seem to have similar baroreflex activity when at rest or in the orthostatic stress, but after the maximal exercise test, women had higher SBR compared to men.
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Revel, Aurélia. "Innervation sympathique et hémodynamique cérébrale chez le rat." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00819175.
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Ce travail avait pour but de déterminer, chez le rat vigil, le rôle de l'innervation sympathique dans le contrôle de l'hémodynamique cérébrale 1/ au cours d'une période d'activité normale d'environ 4 heures, et 2/ lors d'une augmentation aiguë de la pression artérielle (PA) induite par un stress émotionnel (jet d'air). Les débits sanguins dans les artères carotides internes (DSCa) ont été mesurés grâce à des sondes Doppler chroniquement implantées, chez des rats intacts ou ayant subi l'exérèse unilatérale du ganglion cervical supérieur. Le stress induit une élévation brusque et importante de la PA qui s'accompagne d'une hyperémie et d'une vasodilatation beaucoup plus marquées du côté dénervé que du côté innervé. Dans les conditions de base, l'analyse spectrale révèle une augmentation de la variabilité du DSCa du côté dénervé. La cohérence entre les deux DSCa, qui fournit un index de corrélation linéaire dans le domaine fréquentiel, a été calculée avant (cohérence ordinaire) et après élimination mathématique de l'influence de la PA (cohérence partielle). Les cohérences ordinaire et partielle sont diminuées par la sympathectomie unilatérale dans une bande de fréquences comprises entre 0,01 et 0,1 Hz. Ceci suggère un rôle modulateur important de l'innervation sympathique vis-à-vis de ces fluctuations lentes des DSCa. Ces résultats montrent que chez le rat vigil, l'innervation sympathique exerce un rôle protecteur de la circulation cérébrale face aux augmentations de PA au cours du stress émotionnel. Par ailleurs, cette innervation module des fluctuations spontanées lentes du débit sanguin cérébral qui ne sont pas directement reliées aux fluctuations de la PA.
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Nilsson, Inga-Lena. "Primary Hyperparathyroidism : A Study of Cardiovascular Dysfunction and its Reversibility After Parathyroidectomy." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5090-3/.
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Leite, Mariana Adami. "Estudo das características antropométricas e das respostas de frequência cardíaca e pressão arterial, e suas respectivas variabilidades, à manobra postural passiva em pacientes com suspeita clínica de síncope neurocardiogênica." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-15012014-112352/.
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A síncope neurocardiogênica (SNC) é caracterizada por perda transitória da consciência e do controle postural, devido a uma hipoperfusão cerebral global de surgimento abrupto, com recuperação rápida e espontânea do paciente ao retornar à posição horizontal. Entretanto, investigações adicionais são necessárias para melhor avaliação das respostas cardiorrespiratórias e autonômicas de pacientes com SNC submetidos ao Tilt-test. O presente estudo teve como objetivo avaliar, em pacientes com história clínica sugestiva de SNC, os efeitos da mudança postural induzidas pelo Tilt-test na pressão arterial (PA) e frequência cardíaca (FC), na variabilidade cardiocirculatória e na sensibilidade barorreflexa (SBR). Além disso, o estudo também avaliou a relação entre a idade, sexo e características antropométricas dos pacientes com as respostas ao Tilt-test, e a relação entre o tempo do início da mudança postural e o momento da síncope, com um ou mais parâmetros acima mencionados. O estudo foi dividido em 3 partes: 1 Estudo retrospectivo de 180 pacientes, com história clínica sugestiva de SNC, mas que apresentaram Tilt-test positivo (TTP) (128 indivíduos) ou negativo (TTN) (52 indivíduos) para síncope; 2 Estudo da variabilidade da frequência cardíaca (VFC), usando-se métodos lineares (Transformada Rápida de Fourier) em pacientes com história clínica sugestiva de SNC, e com respostas positiva ou negativa ao Tilt-test. Foram incluídos 62 pacientes, 31 com Tilt-test positivo e 31 negativo; 3 Estudo da variabilidade da pressão arterial sistólica (VPAS), usando-se métodos lineares (Transformada Rápida de Fourier), e da SBR (Método da Sequência) em pacientes com história clínica sugestiva de SNC, e com respostas positiva ou negativa ao Tilt-test. Foram estudados 33 indivíduos, 16 com Tilt-test positivo e 17 negativo. Estudo 1 Observou-se que a incidência de SNC foi 1,5 vezes maior em mulheres do que em homens. Além disso, os grupos TTP e TTN apresentaram idade e características antropométricas semelhantes entre si, e não houve significância estatística nas correlações entre o tempo do início da posição vertical até a síncope, a idade e as características antropométricas. Estudo 2 Comparando os 2 grupos nos domínios do tempo (SD-iRR, variância-iRR, RMSSD) e da frequência (LF (un), HF (un) e LF/HF) nas fases Pré-Tilt, Tilt e Pós-Tilt, com exceção do iRR (ms), não observou-se diferença entre os grupos. Houve, na fase Tilt, um menor valor do iRR no grupo TTP. O Pré-Tilt comparado ao Tilt, promoveu em ambos os grupos redução do iRR e aumento na razão LF/HF. Estudo 3 Comparando-se os grupos TTP e TTN no Pré-Tilt e Tilt, não houve diferença no LF da PAS e na SBR. O Tilt promoveu, em ambos os grupos, aumento no LF da PAS, redução na SBR. Somente no grupo TTP foi observado aumento no desvio padrão da PAS durante o Tilt. Em conclusão, o estudo 1 demonstrou que a SNC não foi influenciada pela idade e características antropométricas, no que diz respeito à prevalência, e ao tempo de duração entre o início da mudança postural no Tilt-test e o momento do aparecimento da síncope na posição vertical. O estudo 2 demonstrou que indivíduos com suspeita clínica de SNC, e Tilt-test positivo ou negativo não apresentam anormalidades no balanço simpato-vagal cardíaco, mas, apresentaram diferenças no iRR. O estudo 3 não evidenciou diferenças no controle autonômico cardiovascular (LF-PAS e SBR) entre os grupos TTP e TTN no Pré-Tilt e Tilt. Os estudos 2 e 3 mostraram que com a metodologia utilizada na análise da VFC e VPAS não foi possível detectar anormalidades significativas da modulação autonômica cardiovascular nos grupos TTP e TTN, e desse modo, prever na posição vertical do Tilttest, se um paciente com história clínica sugestiva de SNC apresentará ou não síncope.Neurocardiogenic syncope (NCS) is characterized by transient loss of consciousness and postural control, due to abrupt global cerebral hypoperfusion, with rapid and spontaneous recovery after changing the patient to horizontal position. However, further investigations are necessary to better understand the cardiorespiratory and autonomic responses to the Tilt-test in NCS patients. The present study aimed to evaluate, in patients with a history suspicion of NCS, the effects of postural change (Tilt-test) on blood pressure (BP) and heart rate (HR), on the cardiovascular variability and baroreflex sensitivity (BRS). Furthermore, the study also assessed the relationship between age, sex and anthropometric characteristics with the Tilt-test responses, and the relationship between the time period taken to experience syncope following postural change and the above cited parameters. The study was divided into three parts: 1 A retrospective study with 180 patients with a history suspicion of NCS, that experienced (TTP; 128 individuals) or not (TTN; 52 individuals) syncope following Tilt-test; 2 A study of the heart rate variability (HRV), assessed by linear methods (Fast Fourier Transform), in patients with a history suspicion of NCS and that experienced, or not, syncope following Tilt-test. The study included 62 patients (31 in TTP group and 31 in TTN group); 3 A study of the systolic blood pressure variability (SAPV), using linear methods (Fast Fourier Transform), and of the BRS (Sequence Method) in patients with a history compatible with NCS and that experienced, or not, syncope following Tilt-test. The study included 33 patients (16 in TTP group and 17 in TTN group). Study 1 it was observed that the incidence of NCS was 1.5 times greater in women than in men. Furthermore, groups TTP and TTN showed age and anthropometric characteristics similar to each other and no statistical significance was observed in the correlations among the time period taken to experience syncope following postural change and age and anthropometric characteristics. Study 2 The analysis of the cardiovascular variability, by means of time (SD-iRR, variance-iRR, RMSSD) and frequency (LF (nu), HF (nu) and LF/HF) domain methods, revealed no differences between groups in the Pre-Tilt, Tilt and Post-Tilt phases. However, iRR (ms) was found different between groups. During the Tilt phase, TTP group has shown lower iRR as compared to TTN. Also, TTP and TTN groups exhibited lower iRR and higher LF/HF ratio during Tilt-test as compared to Pre-Tilt phase. Study 3 Comparing the TTP and TTN groups, no statistical differences were found in the LF power of SAP and BRS in both Pre-Tilt and Tilt phases. Following Tilt-test it was observed an increase in LF power of SAP and a reduction in BRS. TTP group showed higher SAP standard deviation during the Tilt phase. In conclusion, study 1 demonstrated that NCS incidence and the time period taken to experience syncope following postural change were not influenced by age and anthropometric characteristics. Study 2 has shown that patients with a history suspicion of NCS, that experienced or not syncope following Tilt-test do not show abnormalities in the sympatovagal balance, but exhibited changes in the iRR. Study 3 showed that the cardiovascular autonomic control (LF-SAP and BRS) is not different between the TTP and TTN groups, in the Pre-Tilt and Tilt phases. Studies 2 and 3 have shown that the methods employed in the analysis of HRV and SAPV were unable to reveal abnormalities in the cardiovascular autonomic modulation in TTP and TTN groups, and thus, can not predict if a patient with a history suspicion of NCS will experience or not syncope during Tilt-test.
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Pereira, Erlick Abilio Coelho. "Deep brain surgery for pain." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:84c885f3-201a-4c6d-90ab-502194cd93ae.
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Deep brain stimulation (DBS) is a neurosurgical intervention now established for the treatment of movement disorders. For the treatment of chronic pain refractory to medical therapies, several prospective case series have been reported, but few centres worldwide have published findings from patients treated during the last decade using current standards of technology. This thesis seeks to survey the current clinical status of DBS for pain, investigate its mechanisms and their interactions with autonomic function, its clinical limitations and ablative alternatives. Presented first is a review of the current status of analgesic DBS including contemporary clinical studies. The historical background, scientific rationale, patient selection and assessment methods, surgical techniques and results are described. The clinical outcomes of DBS of the sensory thalamus and periventricular / periaqueductal grey (PAVG) matter in two centres are presented including results from several pain and quality of life measures. A series of translational investigations in human subjects receiving DBS for pain elucidating mechanisms of analgesic DBS and its effects upon autonomic function are then presented. Single photon emission tomography comparing PAVG, VP thalamus and dual target stimulation is described. Somatosensory and local field potential (LFP) recordings suggesting PAVG somatotopy are shown. ABPM results demonstrating changes with PAVG DBS are given and Portapres studies into heart rate variability changes with ventral PAVG DBS are detailed. Investigations using naloxone are then shown to hypothesise separate dorsal opioidergic and ventral parasympathetic analgesic streams in the PAVG. Finally, cingulotomy in lung cancer to relieve pain and dyspnoea results are discussed in the context of altering pain and autonomic function by functional neurosurgery. Pain and autonomic interactions and mechanisms in deep brain surgery for pain are then discussed alongside its limitations with proposals made for optimising treatment and improving outcomes.
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Morais, Tércio Lemos de. "Avaliação da modulação simpática e vagal, da pressão arterial e do perfil metabólico de mulheres jovens usuárias e não usuárias de contraceptivo hormonal oral combinado." Universidade Nove de Julho, 2014. http://bibliotecadigital.uninove.br/handle/tede/1144.
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Evidence suggests the association of combined oral contraceptives (COC) with the development of hypertension, metabolic dysfunction and cardiovascular risk. The mechanisms involved in such association are not fully understood. It was demonstrated in previous studies by our group that there is an autonomic modulation imbalance before the development of hypertension in people with a positive family history of hypertension. This project evaluates the impact of combined oral contraceptives on anthropometric (BMI, abdominal circumference), hemodynamic (blood pressure, heart rate, cardiac outflow and total peripheral resistance), metabolic (serum glucose, total cholesterol and triglycerides) and autonomic (serum cathecolamines, heart rate variability) in normotensive and in hypertensive women (18 to 35 years of age) under combined oral contraceptives. We did not observe any significant change in blood pressure, hemodynamic and autonomic variables in the normotensive group under second and third generation of combined oral contraceptives. The same with hypertensive women under drospirenona (DRSP) and etinilestradiol (EE). Concerning the metabolic variables (against the control group), the normotensive women under combined oral contraceptives showed an increase in both means of total cholesterol (165.95 ± 29.21 vs 189.11 ± 28.96) and triglycerides (72.62 ± 23.44 vs 110.07 ± 40.60). Hypertensive women under DRSP+EE had also a significant increase in triglycerides when comparing basal (72.62 ± 23.44 vs 110.07 ± 40.60) with the later 6 month period( 72.62 ± 23.44 vs 110.07 ± 40.60). Moreover, in this same group of hypertensive women under Drospirenone-containing oral contraceptive, no change was found in potassium levels, the aldosterone-renin-angiotensin system or pharmacological interactions with anti-hypertensive drugs. Our conclusion is that second and third generation combined hormonal oral contraceptives causes no significant change in blood pressure or hemodynamic and autonomic variables. Also, DRSP+EE demonstrates a safe profile when used by young hypertensive women under anti-hypertensive drugs. No detectable variations in blood pressure and neuro-humoral activation, no hydro electrolyte imbalance and no metabolic change (except for a slight triglycerides augmentation) was encountered.
Existem evidências da associação entre uso de contraceptivo hormonal oral combinado (CHOC) com o desenvolvimento de hipertensão arterial, distúrbios metabólicos e risco cardiovascular. Os mecanismos envolvidos ainda não estão totalmente elucidados. Estudos prévios do nosso grupo demonstraram que há um desequilíbrio na modulação autonômica, mensurada pela análise da variabilidade da frequência cardíaca, antecedendo o desenvolvimento de HAS em filhos de hipertensos. No presente projeto, avaliamos o impacto do uso de CHOC em parâmetros antropométricos (índice de massa corpórea, circunferncia abdominal), hemodinâmicos (pressão arterial, frequencia cardíaca, débito cardíaco e resistência vascular periférica), metabólicos (glicemia, colesterol total e triglicérides), e autonômicos (dosagem sérica de noradrenalina e variabilidade da frequência cardíaca) em mulheres normotensas e hipertensas usuárias e não usuárias de CHOC, na faixa etária de 18 a 35 anos de idade. Como resultados, não observamos mudanças significativas na pressão arterial, variáveis hemodinâmicas e autonômicas na coorte de mulheres normotensas usuárias e não usuárias de CHOC de segunda e terceira geração, bem como no estudo prospectivo de mulheres hipertensas usuárias de drospirenona (DRSP) mais etinilestradiol (EE). Com relação às variáveis metabólicas, comparado ao grupo controle, a coorte de mulheres normotensas usuárias de CHOC apresentou valores médios de colesterol total (165,95 ± 29,21 vs 189,11 ± 28,96) e triglicérides (72,62 ± 23,44 vs 110,07 ± 40,60) superiores aos observados no grupo das não usuárias. As mulheres hipertensas usuárias de DRSP+EE, também apresentaram valores médios de triglicérides superiores estatisticamente significantes comparado ao momento inicial (124,3 ± 57,7 vs 174,7 ± 70,6), respectivamente basal e após 6 meses. Ainda no grupo de hipertensas, o uso de CHOC contendo drospirenona não se associou a mudanças na atividade do sistema renina angiotensina aldosterona, não alterou os níveis séricos de potássio, nem apresentou interações medicamentosas com medicamentos anti-hipertensivos usados. Concluímos que o uso de CHOC de segunda e terceira geração não causou alterações significativas na pressão arterial, parâmetros hemodinâmicos e autonômicos, com modesto impacto negativo sobre o perfil lipídico. E a DRSP+EE apresenta um perfil seguro quando usado como contraceptivo num grupo de mulheres hipertensas jovens já em uso de anti-hipertensivos, considerando-se que: não foram detectadas variações nos valores de pressão aretrial e de ativação neuro-humoral, não ocorreram distúrbios hidro eletrolíticos, e nem alterações em parâmetros metabólicos, execeto um leve aumento nos níveis de triglicérides.