Learning of a positive diagnosis of HIV may be one of the most challenging and stressful events in life. The memory of this event is emotionally laden, and even years later evokes an emotional response. Similarly, many people living with HIV (PLH) have memories of the first time they were treated differently because of their diagnosis. While research frequently examines the subjective of stress, few studies have examined biological markers of stress in people living with HIV. Heart Rate Variability offers a non-invasive measure of stress. Beyond serving as a biological marker for stress, changes in HRV are also associated with emotional functioning. Research demonstrates decreased HRV levels in patients with Depression, Anxiety, and PTSD. We conducted a repeated measures MANOVA to examine effects of stress induction on HRV in individuals with high and low levels of HIV-related stigma. We found that the high stigma group was significantly different from the low stigma group in regard to changes in participants’ HRV, Wilks’ λ = .50, F (1, 51) = 11.63, p < .001. A hierarchical linear regression examined the relationship between HRV and other measures of stress (Heart Rate and Blood Pressure). We found that systolic blood pressure and heart rate in the stress condition were predictive of HRV (adjusted R2=.29, F (5,46) =4.07, p<.01). Results of our study support the use of HRV as a measure of stress in HIV-positive adults. Additionally, the results of our study demonstrate significant relationships between stigma, social support and stress in HIV-positive adults.

Master of Science / Department of Computing and Information Sciences / John Hatcliff / The Heart is a specialized muscle that contracts regularly and continuously, pumping blood to the body and the lungs. Heart’s natural Pacemaker, the SA node is responsible for this pumping action by causing a flow of electricity through the heart. These electrical impulses cause the atria and ventricles to contract and thereby pump the blood to different parts of the body. Malfunction of the SA node leads to a disturbance in the heart’s rhythm in which heart beats lower than 60 times a minute ending up with Bradycardia. It also leads to ventricular arrhythmia which disrupts the ability of the ventricles to pump blood effectively to the body. This can cause a loss of all blood pressure leading to cardiac arrest and eventually death. In order to restore the heart’s natural healthy rhythm, an artificial pacemaker is necessary. A Pacemaker adapts to the present condition of the heart and responds to the heart by either pacing or just sensing it. It paces whenever there is some problem in the heart’s electrical activity and inhibits the pace when there is a proper intrinsic beat. There are various modes in which Pacemaker can operate based on the condition of the heart. Ventricles and atria are individually paced in few modes such as VOO, VVT, VVI, AOO, AAT, and AAI and paced together in some modes such as DVI, DI, DDD, DDDR as per the requirement of the heart. The main goal of this report is to understand the various modes, their nomenclature, working strategy, developing the pseudo code and implementing different modes namely VOO, AOO, VVI, AAI, VVT and AAT modes using an academic, dual chamber pacemaker.

Thesis (MSc. (Human Physiology, Faculty of Health Sciences))--University of Pretoria, 2008. / Summary in English. Includes bibliographical references.

The purposes of the study were to compare ratings of perceived exertion of aerobic dance and treadmill performances under equal work loads and to compare ratings of perceived exertion by males and females in aerobic dance and treadmill work. Subjects were twenty-six college men and women in co-educational conditioning classes. Heart rates were monitored after work bouts and perceived exertion was determined using Borg's RPE scale. Data were analyzed by a two-way analysis of variance with repeated measures. Conclusions of the investigation were: (1) aerobic dance is perceived as less strenuous than the treadmill under equal work loads, and (2) males and females perceive aerobic dance as less strenuous than the treadmill under equal energy bouts.

The resume of this master´s thesis is to introduce reader into principal component analysis (PCA), namely, the use of PCA for analysis of ECG. This method allows to reduce quantity of the data without loss of useful information. That is why PCA is widespread for preprocessing of the data for further classification, which this thesis also deals. Data available at the Department of Biomedical Engineering at the University of Technology in Brno were used in this work. All the methods were realized using Matlab.

Chan Wan-Sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 64-76). / Text in English; abstracts in English and Chinese. / Chan Wan-Sze. / Table of Content --- p.II / List of Table --- p.VI / List of Figure --- p.VII / Abstract --- p.1 / Chapter Chapter 1 --- Introduction --- p.4 / Chapter 1.1 --- Background of study --- p.4 / Chapter 1.1.1 --- Oxygen consumption and heart rate --- p.4 / Chapter 1.1.2 --- V02Rand HRR --- p.7 / Chapter 1.1.3 --- Application of the association between V02 and HR- --- p.8 / Chapter 1.2 --- Purpose and significance --- p.9 / Chapter 1.3 --- Operational Definitions --- p.10 / Chapter 1.4 --- Hypotheses --- p.11 / Chapter Chapter 2 --- Review of Literature --- p.12 / Chapter 2.1 --- Exercise prescription for Cardiorespiratory Fitness --- p.14 / Chapter 2.1.1 --- Mode of exercise --- p.14 / Chapter 2.1.2 --- Frequency --- p.15 / Chapter 2.1.3 --- Duration --- p.16 / Chapter 2.1.4 --- Intensity --- p.17 / Chapter 2.2 --- Measurement of exercise intensity --- p.19 / Chapter 2.2.1 --- Rate of Perceived Exertion (RPE) --- p.21 / Chapter 2.2.2 --- Heart Rate (HR) --- p.23 / Chapter 2.3 --- Children and exercise intensity --- p.29 / Chapter 2.4 --- Summary --- p.30 / Chapter Chapter 3 --- Methodology --- p.32 / Chapter 3.1 --- Participants --- p.32 / Chapter 3.2 --- Procedures --- p.32 / Chapter 3.2.1 --- Resting measures --- p.34 / Chapter 3.2.2 --- Peak oxygen uptake (V02peak) testing --- p.34 / Chapter 3.3 --- Equipment and instrumentation --- p.36 / Chapter 3.3.1 --- Body mass and height --- p.36 / Chapter 3.3.2 --- Expired gases collection --- p.37 / Chapter 3.3.3 --- Heart rate measurement --- p.38 / Chapter 3.3.4 --- Determination of oxygen uptake (V02peak) and heart rate (HR) values --- p.38 / Chapter 3.4 --- Statistical Analysis --- p.39 / Chapter Chapter 4 --- Results --- p.41 / Chapter 4.1 --- Descriptive statistics --- p.41 / Chapter 4.2 --- Resting and maximal measures --- p.43 / Chapter 4.3 --- Submaximal exercise --- p.45 / Chapter 4.3.1 --- Phase I: %HRmax versus %V02peak --- p.47 / Chapter 4.3.2 --- Phase II: %HRR versus %V02peak --- p.48 / Chapter 4.3.3 --- Phase III: %HRR versus %V02R --- p.50 / Chapter 4.4 --- Summary of results --- p.53 / Chapter Chapter 5 --- Discussion and Conclusion --- p.54 / Chapter 5.1 --- Phase I: Preliminary findings from basic measures --- p.54 / Chapter 5.2 --- Phase II: %HRmax versus %V02peak --- p.57 / Chapter 5.3 --- Phase III: %HRR versus %V02peak --- p.58 / Chapter 5.4 --- Phase IV: %HRR versus %V02R --- p.60 / Chapter 5.5 --- Limitations of the study --- p.62 / Chapter 5.6 --- Conclusion and implications --- p.62 / Chapter 5.7 --- Recommendations and further studies --- p.63 / References --- p.64 / Appendix A --- p.77 / Appendix B --- p.79 / Appendix C --- p.80 / Appendix D --- p.81 / Appendix E --- p.82 / Appendix F --- p.83

Synchronous contraction and relaxation of the myocardium is required to optimize cardiac function. Regional timing of contraction and relaxation is dyssynchronous in many patients with heart failure. Cardiac resynchronization therapy (CRT) is a highly successful treatment for dyssynchronous heart failure. Patients are currently selected for CRT using surface electrocardiogram QRS duration as a measure of dyssynchrony. However, up to 30% of patients selected for CRT show no improvement. This poor response rate may in part be explained by the poor correlation between mechanical dyssynchrony and QRS duration. Thus, better methods to quantify mechanical dyssynchrony in the heart may improve the poor CRT response rate. The overall goal of this project was to develop better methods to diagnose dyssynchrony in the left ventricle (LV). We developed two new methods with different approaches. The first method improved upon existing tissue-Doppler based echocardiographic diagnosis of dyssynchrony by utilizing a cross-correlation (XC) function to quantify dyssynchrony during post-processing as opposed to the quantitatively simplistic time-to-peak analysis that is currently utilized. The second method utilized standard cine cardiac magnetic resonance (CMR) images to quantify the dyssynchrony in the flow of blood within the LV, which may represent a more direct, physiologically relevant measure of dyssynchrony. Specific aim 1 demonstrated that the new XC delay parameters can be quantified accurately with a stationary region of interest and therefore require significantly less post-processing time to calculate compared to the time-to-peak dyssynchrony parameters. Specific aim 2 showed that XC delays are superior to existing time-to-peak dyssynchrony parameters at discriminating patients with LV dyssynchrony from those with normal function. The time-to-peak parameters showed dyssynchrony in approximately half of the normal, healthy volunteers while the XC delay parameters had nearly perfect diagnostic accuracy. The results of specific aim 3 showed that XC delays could diagnose acute, pacing-induced dyssynchrony in young, healthy children with 79% accuracy while the time-to-peak parameters showed accuracies of 71%, 57% and 57%. Specific aim 4 showed that CMR-based quantification of LV internal flow can be used to discriminate patients with dyssynchronous heart failure from normal controls with 95% accuracy.

Intervalos dos batimentos (R-R) vêm sendo considerado pela literatura, como um dos mais promissores meios de análise do sistema autônomo. Porém, diversos monitores e seus métodos, necessitam de validação através da análise dos parâmetros de VFC. O objetivo deste estudo foi validar um instrumento portátil, específico para mensuração dos intervalos dos batimentos (R-R) da marca WCS Pulse. Para a proposta deste estudo, 30 indivíduos do sexo masculino praticantes de Jiu-Jitsu, foram monitorados através de ECG e monitor WCS Pulse. Os parâmetros de VFC: intervalos (R-R), LF, HF e LF/HF foram coletados em pré- exercício, 24 e 48 horas após exercício. Conforme os resultados observados, os instrumentos ECG e WCS Pulse apresentam forte correlação e forte coeficiente de correlação intra-Classe, nos parâmetros de VFC (LF, HF e LF/HF). Por outro lado, quanto aos valores de Student t aplicados nos intervalos (R-R), foi observado diferença significativa entre os instrumentos (p<0.05) em todos os momentos da pesquisa. Através deste estudo, pode-se considerar que o monitor dos intervalos dos batimentos (R-R) da marca WCS Pulse é uma ferramenta de biomarcador (não invasivo) eficaz. Nesta esteira, o equipamento de monitoração dos intervalos (R-R) WCS Pulse, demonstrou um grau de concordância para a utilização em centros de treinamentos esportivos e ciências da saúde; porém, os parâmetros de resolução de amostragem do instrumento WCS Pulse, deve ser mais bem observado quando for comparado com instrumentos existentes no mercado e ou eletrocardiogramas. / The RR interval has been considered in the literature, the most promising analysis autonomous system. However, several monitors and validation methods is necessary through of the HRV parameters analysis. The aim of this study was, validate portable specific instrument to measurement RR interval WCS Pulse. For the proposal of this study, 30 male practitioners of BJJ were monitored through ECG and monitor Pulse WCS in different ways. The parameters of HRV: RR interval, LF, HF and LF / HF were collected in pre-exercise, 24 and 48 hours after exercise. Results: ECG instruments and WCS Pulse demonstrated strong correlation (r), and strong values to coefficient of intra-class in HRV parameters (LF, HF and LF / HF). In the other hand, the Student t values applied on the RR interval, was observed significant difference between the instruments in all moments of the research (p <0.05). Through this study, we consider that monitor RR interval WCS Pulse is effective biomarker tool (noninvasive). Thus, the equipment monitoring of RR intervals WCS Pulse, showed highs degree of agreements for use in sports training centers and Health Sciences; However, the instrument sampling resolution parameters, WCS Pulse should be more observed when compared to existing instruments in the market and electrocardiogram.

\ / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished

Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished