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URI permanente desta comunidadehttps://repositorioacademico.universidadebrasil.edu.br/handle/123456789/914
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5 resultados
Resultados da Pesquisa
Item Diagnóstico clínico automatizado a partir do uso de métodos de análise multivariada aplicados a sinais de eletrocardiograma(Universidade Brasil, 2020) Zena, Antonio Chavez; Mendes, Thiago de Oliveira; Santos, Laurita dosThis work presents a study of methods applied to pattern recognition of heart rate variability parameters obtained from electrocardiogram (ECG) for the aid of automated clinical diagnosis of various diseases associated with the heart, using multivariate statistical methods and computational machine learning. For this purpose, the electrocardiograms signs of 137 volunteers clinically diagnosed with normal sinus rhythm (NSR), with n = 54 individuals, which will represent the control group, and two clinical conditions formed by individuals with congestive heart failure (CHF), with n = 29 individuals or suppression of cardiac arrhythmia (CAST), with n = 54 individuals, considering these two clinical conditions, such as the case groups. All these signals were obtained from the PhysioNet, which covers a set of real biomedical signals, open source software and from studies consolidated in the literature. A procedure for obtaining characteristic variables of ECG tachograms was described, these variables were modeled by classification approaches of Discriminant Analysis data by Partial Least Squares regression (PLS-DA) and Artificial Neural Networks (ANN), aiming at the diagnosis of two clinical conditions when compared with a control group. Data matrices of variables associated with the time domain, frequency domain and obtained by non-linear methods were considered separately, each one, and all of these in a single data matrix, of statistical parameters associated with heart rate variability. The figures of merit showed that there is a pattern in the behavior of the tachogram parameters that may be used for clinical diagnostic aid. Both congestive heart failure and the classification and prediction of samples belonging to the cardiac arrhythmia suppression were satisfactorily obtained, with an area under the ROC curve close to 0.9. The PLS-DA model demonstrated the best data classification results, where congestive heart failure was diagnosed with rates of 90.9% of sensitivity and selectivity of 85.7% and suppression of cardiac arrhythmia was predicted with rates of 75.0% of sensitivity and 100.0 % of selectivity, suggesting that clinical diagnosis assisting real time and a personalized prognosis can become a reality that will contribute positively to medical practice.Item Variabilidade da frequência cardíaca e níveis de cortisol salivar entre policiais militares(Universidade Brasil, 2020) Araújo, Liliam Mendes de; Santos, Laurita dosThis study aims to validate the relationship between heart rate variability patterns and salivary cortisol levels in military police officers, based on measurements induced by the Trier social Stress Test (TSST). This is a cross-sectional experimental study, conducted between the months of February and November 2020, involving 30 male police officers in regular working activities for a year or more, aging over 18. The study excluded individuals with high blood pressure, diabetes, those carrying a pacemaker or a transplanted organ and teachers. The subjects were submitted to the TSST and their HRV and saliva (in order to measure cortisol levels) were taken at three moments: basal period and prior to the TSST, immediately after the test and 20 minutes after the second collection. For collecting the temporal series of RR intervals, we used the Polar®, v800 monitor. The project was approved by the Ethics and Research Committee of Universidade Brasil, CAAE: 85502418.0.0000.5494. The results showed that the TSST induced a physiological response which can be visualized in the cortisol concentrations (0.272 ± 0.221 e mean 0.220 µg/dL), p = 0.0001. With HRV analyzed by using linear time domain, frequency domain and non-linear methods, it was possible to identify that some variables show statistic difference (p< 0.05) among the distinct moments of the experimental protocol. Among the main contributions of this study, it was possible to point out the importance of cortisol, showing that it is related to HRV linear and non-linear measurements, as well as the strong positive linear correlation between the HRV variables. Thus, HRV used as an information tag of the physiological impacts caused by the experimental stress causes, in addition to being adopted as a complementary tool for police officers’ clinical evaluation, can also be an important biomarker to promote health. Promoting military police officers’ health is a big challenge, once strategies aimed at fighting stress related to police activities must be implemented so as to improve the quality of life and health of these professionals.Item Laser Speckle Contrast Analysis (LASCA) aplicada à avaliação de estresse(Universidade Brasil, 2024) Carvalho, Claudia Maria Sousa de; Amaral, Marcelo Magri; Santos, Laurita dosDespite being physiologically normal, exaggerated and continuous exposure to stress, which exceeds the individual's tolerance capacity, can result in harm to health. The objective of this study was to apply the optical technique Laser Speckle Contrast Analysis (LASCA) to assess stress. This is a cross-sectional, descriptive, experimental study, with a quantitative approach, developed with undergraduate and postgraduate students, at a Higher Education Institution, in São Paulo (SP). The sample consisted of 27 (twenty-seven) participants, randomly distributed. The inclusion criteria were: undergraduate and postgraduate students, of both sexes, aged 18 or over, regularly enrolled. Those who self-reported having cardiovascular complications or using medication that altered cardiovascular functioning, suspected or confirmed pregnancy, physical limitations and women in their menstrual period were excluded. Data collection took place in June and August 2021 and all protective measures were adopted in relation to the coronavirus pandemic. Participants underwent cardiac signal acquisition to analyze heart rate variability, obtained using an electrocardiogram and a Polar V800 heart rate monitor, for 15 minutes. Simultaneously, the LASCA application was developed to obtain images using the MoorFLPI (Full-Field Laser Perfusion Imager) equipment. Next, participants underwent a physical effort test using an electric treadmill for 15 minutes, following the Bruce protocol. After resting for 5 minutes, cardiac signals and LASCA images were collected again, following the same protocols as in the initial phase. The project was approved by the Ethics and Research Committee of Universidade Brasil, under Opinion No. 4.724.843. Equivalent results were found regarding HRV measurements when comparing the LASCA technique and conventional methods, enabling the capture of signs of physiological changes present in the individual's state of stress. Thus, the results point to the feasibility of the LASCA technique to obtain images compatible with the heart rate pulsation pattern from the stress generated in situations of physical effort.Item Estudo da variáveis e variabilidade da frequência cardíaca nos nascidos a termo em um hospital público de Santarém - PA(Universidade Brasil, 2022) Cardoso, Marina Chahini; Santos, Laurita dosThis study aimed to evaluate the findings of anthropometric variables and heart rate variability (HRV) in full-term newborns (NBs), correlating them with the socioeconomic factors of the parents of the NBs. Santarém, in the state of Pará. This is a descriptiveanalytical study, with a quantitative, transversal, documentary, comparative and prospective approach, using information collected from the medical records of 49 NBs, as well as the follow-up during the period of 4 months of these NBs. Data on the life habits of the parents of the participating NBs were obtained from a questionnaire applied to the mothers and the use of the Polar V800 in the NBs, to obtain information about HRV. The project was approved by the Research Ethics Committee of Universidade Brasil. The parents of the newborns in the study are adults between the ages of 20 and 29, brown, of normal weight, with a monthly income of one to two minimum wages. Most mothers had a slightly elevated BMI during pregnancy, with a tendency to normalize over the postpartum months. The dietary profile of parents is characterized by the consumption of proteins, carbohydrates, fruits and various vegetables. The evolution of anthropometric measurements: weight, length, BMI (body mass index) and HC (head circumference) of the newborns, followed what was considered normal by the WHO. The HRV metrics in the time domain, frequency domain and non-linear analyzed, showed a lower activity of the autonomic nervous system in the neonatal period in relation to the subsequent periods, within the study range, which can be attributed to the stressful events during the neonatal period. adaptation to the external environment. The HRV was used as a tool to determine a healthy evolution of the homeostatic system of NBs. Correlations of HRV variables with the parents' anthropometric and socioeconomic parameters did not show statistical significance. Even so, it was possible to demonstrate the evolutionary importance of the autonomic nervous system, relating it to linear and non-linear measures of HRV, with HRV being used as a marker of the adaptive physiological impact of NBs. As a benefit of the evaluation method, we must think that the knowledge of the HRV variables of a population of NBs should be used as a strategic marker in the promotion of health and quality of life of a population.Item Desenvolvimento de detector de baixo custo para captação e análise de séries temporais de intervalos RR(Universidade Brasil, 2024) Rizzato, Fernando Kendy Aoki.; Santos, Laurita dosDigital health (e-Health) improves quality and life expectancy, with accessible devices like smartphones monitoring vital signs. In cardiology, due to the high mortality of cardiovascular diseases, the electrocardiogram (ECG) is crucial for assessing the heart's electrical activity and determining treatments. The prototype also applies linear and nonlinear analysis methods to characterize Heart Rate Variability (HRV), calculating indices such as RMSSD, standard deviation of heart rate, and geometric parameters of the Poincaré Plot. The system's validation involved comparing the measurements obtained by the prototype with a conventional ECG device in a population of individuals with different cardiovascular conditions. The results showed that for most time-domain and frequency-domain parameters, there were no statistically significant differences between the data collected by the prototype and the conventional ECG. However, parameters such as mean RR and mean HR showed significant differences. Linear regression analysis indicated a strong correlation between the HRV indices obtained by the prototype and the conventional method. The developed prototype proved to be an effective tool for capturing and analyzing RR intervals and HRV, providing results comparable to traditional methods and showing promise for clinical use in cardiovascular health assessment. To ensure the robustness of the data, adaptive analyses and statistical measures were conducted, utilizing Student's t-test, Mann-Whitney test, and linear regression, with a significance level of p < 0.05. This approach ensured that the conclusions drawn were based on solid and reliable evidence.