Análise morfofuncional ecocardiográfica em condições de repouso e de esforço isométrico manual, correlacionada à função autonômica cardíaca em indivíduos normais e em portadores das diferentes formas da doença de Chagas

• Autor(es): Vasconcelos, Daniel França
• Data: 2010
• Origem: Oasisbr
• Assunto(s): Ecocardiografia; Chagas, Doença de; Cardiologia
• Tipo de Documento: Tese de doutoramento
• Idioma: Português

Descrição

Tese (doutorado)—Universidade de Brasília, Faculdade de Medicina, 2007.

Justificativa: A doença de Chagas, apesar do controle, persiste como sério problema de saúde pública nos países em desenvolvimento, acometendo entre 15 e 20 milhões de indivíduos. Vários estudos sobre a função autonômica na doença de Chagas têm sido realizados. Na forma indeterminada, os estudos são escassos e com resultados conflitantes. O real papel da disfunção autonômica na evolução da doença não está bem estabelecido. Objetivos: Os objetivos do presente estudo foram: a) avaliar a função autonômica cardíaca por meio da variabilidade da freqüência cardíaca e as variáveis morfofuncionais ecocardiográficas em indivíduos portadores de cardiopatia chagásica e naqueles com a forma indeterminada da doença comparando-os entre si e com indivíduos saudáveis; b) correlacionar as variáveis morfofuncionais ecocardiográficas com as variáveis da função autonômica. Indivíduos e métodos: Foram avaliados 45 indivíduos, sendo 17 portadores da forma indeterminada (5 homens) com idade mediana de 39anos (variação interquartil 35-45,5), 13 portadores da forma cardíaca (7 homens) com idade mediana de 44 anos (35,5-49,5) e 15 indivíduos saudáveis (9 homens) com idade mediana de 43 anos (40-46). Os grupos foram semelhantes estatisticamente quanto à idade e ao gênero. Todos os indivíduos foram submetidos ao estudo da variabilidade da freqüência cardíaca (VFC) em registro eletrocardiográfico de 5 minutos na posição supina e 5 minutos na posição ortostática ativa com a obtenção de índices temporais e espectrais da variabilidade da freqüência cardíaca. Em seguida, os indivíduos foram submetidos ao ecocardiograma em repouso, durante o esforço isométrico com 30% da capacidade voluntária máxima, e 3 minutos após o esforço. Os grupos foram comparados pelo Teste de Kruaskal-Wallis, seguido pelo teste de Dunn. A análise correlativa entre as variáveis ecocardiográficas e os índices da função autonômica cardíaca foi feita pelo teste de Spearman. Resultados: Na análise dos resultados, os índices temporais da VFC (SDNN, CV, pNN50 e r-MSSD) se mostraram significativamente (0,0003

Background: Chagas’ disease, until ours days, persist as a public health challenge, with about 15 to 20 million subjects infected in developing countries of Latin America. Several studies about autonomic dysfunction in Chagas’ disease have been done. However, studies involving the indeterminate form of the disease are scarce and the results are apparently conflicting. The real meaning of autonomic impairment in pathogenesis and evolution of Chagas’ disease still persist. Objectives: The objectives of the present study are: a) evaluate the cardiac autonomic function by five minutes heart rate variability and the morphologic and functional parameters using echocardiographic register; b) to correlate the morphological and functional echocardiographic parameters with temporal and spectral heart rate variability indexes. Methods: Time- and frequency-domain of 5-minute heart interval rate series variability in supine and standing position, and Doppler echocardiographic left systolic and diastolic morph-functional parameters were obtained at rest, during handgrip at 30% of maximal voluntary capacity and after 3 minutes of recovery. Variables were comparatively evaluated in 17 chagasic with indeterminate form, 13 with heart disease and in 15 control healthy subjects using the Kruskal-Wallis Test followed by the Dunn’s multiple comparative test at a significance level of p<0.05. For correlative analyses between morph-functional echocardiographic and autonomic indexes the Spearman correlation coefficient were applied. Results: In the supine position, reduced time-domain (SDNN, CV, pNN50, r-MSSD) (p=0.0002-0.0005) and absolute frequency-domain (total power, low- and high-frequency power) (p=0.0001-0.003) indexes were observed in both chagasic groups. In standing position, time-domain indexes were reduced only in heart disease group (p=0.009-0.01), while frequency-domain indexes in both chagasic groups (p=0.002-0.004). Sympathovagal balance (normalized low- and high-frequency power, low-to-high-frequency power ratio) remained comparable in chagasic and control groups in both postures (p=0.21-0.78). No significant differences between the three groups were observed for any achocardiographic variable (p=0.07-0.77). In indeterminate form the results of correlative analyses shows a inverse and significative correlation between mitral flow E-F slope and r-MSSD (rs=-0.57; p=0.02) and absolute High Frequency spectral area (HF) (rs=-0.57; p=0.02). Between E/A ratio and LF/HF ratio (rs=-0.59; p=0.01), e’/a’ ratio and LF/HF (rs=-0.48; p=0.05). The correlation was positive between E/A and e’/a’ ratio and normalized HF area (rs=0.59; p=0.01 and 0.50; p=0.04). In cardiac form, the correlation was positive and significative between both EF and ∆d% with MiRR sup (rs=0.64; p=0.02), r-MSSD (rs=0.63; p=0.02), Total Power ort (rs=0.57; p=0.04), absolute LF ort (rs=0.62; p=0.02). The Vcf agaisnt MiRR sup (rs=0.64; p=0.02), ort (rs=0.56; p=0.05), r-MSSD ort (rs=0.76; p=0.002), absolute LF ort (rs=0.64; p=0.02). In variables of diastolic function the correlative analyses was positive and significative between E/A and normalized LF area sup (rs=0.66; p=0.01) and LF/HF ratio sup (rs=0.68; p=0.01), between E-F slope and normalized HF area ort (rs=0.57; p=0.04), E/e’ and normalized LF area sup (rs=0.62; p=0.02) and LF/HF ratio sup (rs=0.62; p=0.03). The correlative analyses was positive and inverse between E/A and normalized HF sup (rs=-0.66; p=0.01), between E-F slope and normalized LF area ort (rs=- 0.57; p=0.04) and LF/HF ratio (rs=-0.57; p=0.04) and E/e’ ratio with normalized HF area sup (rs=-0.62; p=0.02). The Tei index had a positive and significative correlation with normalized HF area sup (rs=0.62; p=0.02) in cardiac form. This index was inverse with normalized LF area sup (rs=-0.62; p=0.02) and LF/HF ratio sup (rs=-0.62; p=0.02). There was not a significativa correlation between Tei index and echocardiographic parameters in indeterminate forma of Chagas’ disease. Conclusions: In this study, the Chagas’ disease presents with depressed absolute short- term heart interval variability, without a impaired sympathovagal balance in cardiac and indeterminate forms, more severe but not significant in the first. There are no differences in morph-functional variables by echocardiography between chagasic with oligo or no symptoms and control groups. The correlative analyses suggest that the autonomic impairment and has a significativa correlation with echocardiographic systolic and diastolic parameters in cardiac and indeterminate form of Chagas’ disease, without a necessary straight relationship of cause and effect.