Título:	Atenuação da modulação vagal com o envelhecimento : análise da variabilidade de frequência cardíaca, sensibilidade do barorreflexo e arritmia sinusal respiratória
Autor(es):	Oliveira Júnior, Evandro da Costa
Orientador(es):	Oliveira, Flavia Maria Guerra de Sousa Aranha
Assunto:	Sistema nervoso autônomo Frequência cardíaca Eletrocardiograma Arritmia respiratória Pressão arterial
Data de publicação:	20-Set-2017
Data de defesa:	4-Jul-2017
Referência:	OLIVEIRA JÚNIOR, Evandro da Costa. Atenuação da modulação vagal com o envelhecimento: análise da variabilidade de frequência cardíaca, sensibilidade do barorreflexo e arritmia sinusal respiratória. 2017. xv, 70 f., il. Dissertação (Mestrado em Engenharia de Sistemas Eletrônicos e Automação)—Universidade de Brasília, Brasília, 2017.
Abstract:	The aging process leads to diverse changes in the human organism, including in autonomic system nervous (SNA) modulation. In this study, indices of heart rate variability (VFC), baroreflex sensitivity (BRS) and respiratory sinus arrhythmia (RSA) were calculated through the processing of electrocardiogram signals, arterial pressure and respiration, in the domains of frequency and time. The VFC indicator was estimated in the frequency domain by means of the spectral density (PSD) of the R-R intervals(IRR), resulting from the electrocardiogram signal, for the high and low frequencies. The indices of BRS were obtained through the relation between the spectrum of IRR and systolic blood pressure (PAS) and the association between the signs of IRR and PAS in the frequency response function (FRF). The spectral indices of the BRS were also obtained using coherence between the signals and the average of the high and low frequency regions (index ). The method of the sequence was used to obtain temporal indices of the BRS, as well as the method of impulse response(RI), which is a method that uses the autorregressive model with input exogenous (ARX) and allows to obtain the impulse response between the signals of PAS and IRR. The RSA indicator was obtained similarly to the BRS indicator, in which DEP and FRF were used to produce spectral indices, and the impulse response for obtaining the temporal indices, in which the relations between IRR signals and instantaneous pulmonary volume (VPI) were used.The data were used for healthy young and elderly subjects from the Fantasia database of Physionet. The database contains electrocardiogram and respiration data of 40 volunteers, 20 young (21 and 34 years old), and 20 elderly (68 and 85 years old) adults. The blood pressure data exists for half the group. Each subgroup (young and elderly volunteers) has an equal number of men and women. The vital signs of the volunteers were obtained in a supine position while watching the film Fantasia (Disney, 1940) during the experiment. The statistical analyses of the indices obtained have shown that the VFC is a strong indicator of changes in the SNA of young and elderly people. Although it is a very accepted indicator in literature, it is not the only indicator capable of making that distinction. It was possible to identify a decrease in the BRS of young adults compared to elderly adults at the low frequencies using the FFT method (P = 0.027) and Welch (P = 0.012), and it was showed that there was a pressure influence on the system. Respiratory mechanisms were also affected by aging, and FRF’s results and impulse response were affected too. The results showed that FRF indicators at low frequencies using FFT had P<0.05, and P=0.0134 for the Welch method. At the high frequencies, it was also obtained significant statistical relevance in the two methods with P<0.01. In the analysis of the magnitude of the response to the impulse, it was obtained P=0.003, and P=0.008 for the dynamic gain, which.
Unidade Acadêmica:	Faculdade de Tecnologia (FT) Departamento de Engenharia Elétrica (FT ENE)
Informações adicionais:	Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2017.
Programa de pós-graduação:	Programa de Pós-Graduação em Engenharia de Sistemas Eletrônicos e de Automação
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2017.07.D.24600
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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