Avaliação da variabilidade da frequência cardíaca e ocorrência de quedas em idosos com demência na Doença de Alzheimer
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Data
2019-02-28
Autores
Rodrigues, Evelize Antunes
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Universidade Estadual Paulista (Unesp)
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Introdução: O envelhecimento é um fenômeno mundial com grande impacto na saúde pública. Inerente a esse processo está a prevalência crescente de demências, as quais cursam com comprometimento cognitivo, comportamental e com interferência na capacidade funcional dos idosos. A Doença de Alzheimer (DA) é a causa mais prevalente de demências e estas têm mostrado prejuízo da função autonômica com implicações clínicas que podem ir além do risco cardiovascular. A medida da variabilidade de frequência cardíaca (VFC) afere a função autonômica, mas há divergências nos achados na DA e pouco se sabe sobre a relação dessa função e o risco de quedas entre pacientes dementados. Objetivos: Avaliar a atividade autonômica em indivíduos idosos com demência na doença de Alzheimer e comparar com idosos sem demência, além de verificar possível relação da variabilidade da frequência cardíaca com ocorrência de quedas. Métodos: Análise da VFC avaliada em idosos sem demência (Grupo Controle - GC) e com demência na Doença de Alzheimer (Grupo DA), com uso de cardiofrequencímetro, com medida em único dia em posição supina e ortostática, por dez minutos em cada posição. Foram verificados os componentes da VFC nos domínios tempo e frequência, além do histórico de quedas nos últimos três anos. Resultados: Os grupos foram homogêneos, com predominância do sexo feminino e médias de idade de 81 e 79 anos no grupo demência e controle, respectivamente. Sobre a VFC, no domínio tempo, na comparação intragrupos, entre a posição supina e ortostatismo, o intervalo R-R, que reflete apenas uma medida global da variabilidade, reduziu tanto para DA (p=0,0007) como para GC (p=0,003). No grupo DA houve ainda menores médias dos componentes de influência parassimpática em ortostatismo (RMSSD 12,5 x 8,2 ms; p=0,0008; PNN50 0 x 0%; p=0,018). No Domínio Frequência houve redução da alta frequência (AF) e aumento da baixa frequência (BF) e da relação das duas (BF/AF) para ambos os grupos, todas em unidades normalizadas: [(AF: 39,1 x 17,3; p=0,019 no DA e 47,4 x 24,7; p=0,016 no GC); (BF 60,7 x 82,7; p=0,019 no DA e 52,3 x 74,7; p= 0,016 no GC); (BF/AF: 1,55 x 4,78; p= 0,04 no DA e 1,11 x 3,02; p=0,026 no GC)], refletindo redução da atividade parassimpática e aumento da atividade simpática. No grupo DA houve maior número de quedas (p=0,021). Alguns componentes da VFC apresentaram interação com quedas. Em supino, na presença de queda para o DA, o iRR foi menor e o SDNN (predomínio simpático) também, assim como os componentes no domínio frequência MBF e BF/AF. Em ortostatismo, também para o DA, na presença de quedas, houve maior componente parassimpático (pNN50) e redução do componente simpático (BF/AF). Conclusão: Houve exacerbação simpática e redução parassimpática com ortostatismo para ambos os grupos, mas de forma mais acentuada no DA, o qual ainda mostrou comprometimento parassimpático no domínio tempo. Ainda, ocorreu maior índice de quedas no grupo DA com interação de componentes da VFC na presença de queda também neste grupo.
Introduction: Aging is a worldwide phenomenon with great impact on public health. Inherent in this process is the increasing prevalence of dementias, which occur with cognitive, behavioral impairment and interfere with the functional capacity of the elderly. Alzheimer's disease (AD) is the most prevalent cause of dementia and these have shown impairment of autonomic function with clinical implications that may go beyond cardiovascular risk. Measurement of heart rate variability (HRV) has been performed to verify autonomic function, but there are divergences of the findings in AD, and little is known about the relationship of this function and the risk of falls among dementia patients. Objectives: To evaluate the autonomic activity in elderly individuals with dementia in Alzheimer's disease compared to the elderly without dementia. In addition to verifying possible relationship of heart rate variability with occurrence of falls. Methodology: HRV analysis evaluated in elderly without dementia (Control Group - CG) and with dementia in Alzheimer's Disease (Group AD), using a cardiofrequency meter, measured on a single day in a supine and orthostatic position, for ten minutes in each position. The HRV components in the Time and Frequency domains were verified, as well as the history of falls in the last three years. Results: The groups were homogeneous, with a predominance of females and mean age of 81 years and 79 years for dementia and control groups, respectively. The Mental State score was lower in the AD group compared to the control (15 x 27 points, p <0.001), as expected. On HRV, in the Time Domain, in the intragroup comparison, between the supine position and orthostatism, the RR interval, which reflects only one overall measure of variability, reduced both for AD (p = 0.0007) and for GC (p = 0.003 ). In AD, there were even lower averages of the components of atherosclerotic influences in orthostatism (RMSSD 12.5 x 8.2 ms, p = 0.0008, PNN50 0 x 0%, p = 0.018). In the Frequency Domain there was a reduction of the high frequency (AF) and increase of the low frequency (BF) and the ratio of the two (BF / AF) for both groups, all in standard units: [(AF: 39.1 x 17.3 ; p = 0.019 in DA and 47.4 x 24.7; p = 0.016 in GC); (BF 60.7 x 82.7, p = 0.019 in DA and 52.3 x 74.7, p = 0.016 in GC (BF / AF: 1.55 x 4.78, p = 0.04 in DA and (P = 0.021), reflecting a reduction in parasympathetic activity and an increase in sympathetic activity, while in the AD group there were more falls (p = 0.021). In supine, in the presence of a decrease in the AD, the iRR was lower and the SDNN (sympathetic predominance) was also present, as well as the components in the frequency domain MBF and BF / AF. In orthostatism, also for AD in the presence of falls, there was higher parasympathetic component (pNN50) and reduction of the component friendly (BF / AF). Conclusion: There was sympathetic exacerbation and parasympathetic reduction with orthostatism for both groups, but more markedly in AD, which still showed parasympathetic involvement in the time domain. Still, there was a higher rate of falls in the AD group with interaction of HRV components in the presence of falls in this group.
Introduction: Aging is a worldwide phenomenon with great impact on public health. Inherent in this process is the increasing prevalence of dementias, which occur with cognitive, behavioral impairment and interfere with the functional capacity of the elderly. Alzheimer's disease (AD) is the most prevalent cause of dementia and these have shown impairment of autonomic function with clinical implications that may go beyond cardiovascular risk. Measurement of heart rate variability (HRV) has been performed to verify autonomic function, but there are divergences of the findings in AD, and little is known about the relationship of this function and the risk of falls among dementia patients. Objectives: To evaluate the autonomic activity in elderly individuals with dementia in Alzheimer's disease compared to the elderly without dementia. In addition to verifying possible relationship of heart rate variability with occurrence of falls. Methodology: HRV analysis evaluated in elderly without dementia (Control Group - CG) and with dementia in Alzheimer's Disease (Group AD), using a cardiofrequency meter, measured on a single day in a supine and orthostatic position, for ten minutes in each position. The HRV components in the Time and Frequency domains were verified, as well as the history of falls in the last three years. Results: The groups were homogeneous, with a predominance of females and mean age of 81 years and 79 years for dementia and control groups, respectively. The Mental State score was lower in the AD group compared to the control (15 x 27 points, p <0.001), as expected. On HRV, in the Time Domain, in the intragroup comparison, between the supine position and orthostatism, the RR interval, which reflects only one overall measure of variability, reduced both for AD (p = 0.0007) and for GC (p = 0.003 ). In AD, there were even lower averages of the components of atherosclerotic influences in orthostatism (RMSSD 12.5 x 8.2 ms, p = 0.0008, PNN50 0 x 0%, p = 0.018). In the Frequency Domain there was a reduction of the high frequency (AF) and increase of the low frequency (BF) and the ratio of the two (BF / AF) for both groups, all in standard units: [(AF: 39.1 x 17.3 ; p = 0.019 in DA and 47.4 x 24.7; p = 0.016 in GC); (BF 60.7 x 82.7, p = 0.019 in DA and 52.3 x 74.7, p = 0.016 in GC (BF / AF: 1.55 x 4.78, p = 0.04 in DA and (P = 0.021), reflecting a reduction in parasympathetic activity and an increase in sympathetic activity, while in the AD group there were more falls (p = 0.021). In supine, in the presence of a decrease in the AD, the iRR was lower and the SDNN (sympathetic predominance) was also present, as well as the components in the frequency domain MBF and BF / AF. In orthostatism, also for AD in the presence of falls, there was higher parasympathetic component (pNN50) and reduction of the component friendly (BF / AF). Conclusion: There was sympathetic exacerbation and parasympathetic reduction with orthostatism for both groups, but more markedly in AD, which still showed parasympathetic involvement in the time domain. Still, there was a higher rate of falls in the AD group with interaction of HRV components in the presence of falls in this group.
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Palavras-chave
Variabilidade da frequência cardíaca, Doença de Alzheimer, Modulação autonômica cardíaca, Demência, Heart rate variability, Alzheimer’s disease, Cardiac autonomic modulation, Dementia