Insights into the clinical and functional significance of cardiac autonomic dysfunction in Chagas disease

Abstract

INTRODUCTION: Exclusive or associated lesions in various structures of the autonomic nervous system occur in the chronic forms of Chagas disease. In the indeterminate form, the lesions are absent or mild, whereas in the exclusive or combined heart and digestive disease forms, they are often more pronounced. Depending on their severity these lesions can result mainly in cardiac parasympathetic dysfunction but also in sympathetic dysfunction of variable degrees. Despite the key autonomic effect on cardiovascular functioning, the pathophysiological and clinical significance of the cardiac autonomic dysfunction in Chagas disease remains unknown. METHODS: Review of data on the cardiac autonomic dysfunction in Chagas disease and their potential consequences, and considerations supporting the possible relationship between this disturbance and general or cardiovascular clinical and functional adverse outcomes. RESULTS: We hypothesise that possible consequences that cardiac dysautonomia might variably occasion or predispose in Chagas disease include: transient or sustained arrhythmias, sudden cardiac death, adverse overall and cardiovascular prognosis with enhanced morbidity and mortality, an inability of the cardiovascular system to adjust to functional demands and/or respond to internal or external stimuli by adjusting heart rate and other hemodynamic variables, and immunomodulatory and cognitive disturbances. CONCLUSIONS: Impaired cardiac autonomic modulation in Chagas disease might not be a mere epiphenomenon without significance. Indirect evidences point for a likely important role of this alteration as a primary predisposing or triggering cause or mediator favouring the development of subtle or evident secondary cardiovascular functional disturbances and clinical consequences, and influencing adverse outcomes.

Disfunção autonômica e anticorpos contra receptores anti-m2 e anti-β1 em pacientes chagásicos

“…The second step was performed at rest -in which the RRV was analyzed without any stimulus, between the 15 th and 20 th minutes. The third and last phase began in the 20 th minute, when patients were passively tilted at 70° and the complexes were evaluated until the 25 th minute 26 .…”

“…These antibodies are not just epiphenomenon of the destruction of the autonomic nervous system and are independent from cardiac lesions 14,[20][21][22][23] 24 . Among the maneuvers to assess the parasympathetic response, the Respiratory Sinus Arrhythmia (RSA) has been shown to be the most potent stimulus to evoke vagus nerve action 25,26 . In Chagas disease, in the group with no ventricular dysfunction, the evaluation of the autonomic nervous system through the RRV by different methods has shown variable impairment of parasympathetic and sympathetic modulation [27][28][29][30] .…”

Sistema de apoio ao diagnóstico da Doença de Chagas baseado em escalogramas e redes neurais auto-organizáveis

“…Na doença de Chagas, o parasita afeta com intensidade variável a musculatura atrial e ventricular, o tecido de excitação-condução elétrica e a inervação autonômica intrínseca, particularmente a inervação parassimpática (Junqueira Jr, 2012). Estudos baseados em necropsias mostraram, em chagásicos cardiopatas, grau de denervação parassimpática entre 52% e 94% e simpática em torno de 37% (Esteller et al, 1994).…”

“…Estudos baseados em necropsias mostraram, em chagásicos cardiopatas, grau de denervação parassimpática entre 52% e 94% e simpática em torno de 37% (Esteller et al, 1994). Portanto, espera-se observar, nos escalogramas, principalmente depressão da função parassimpática característica da doença de Chagas em suas diferentes formas clínicas, o que pode determinar ou contribuir para a ocorrência de arritmias, morte súbita e progressão da disfunção contrátil (Vasconcelos e Junqueira Jr, 2009;Junqueira Jr, 2012).…”

“…Aproximadamente, metade dos pacientes contaminados com o parasita Trypanosoma cruzi não apresentam sinais clínicos, eletrocardiográficos e radiológicos de envolvimento cardíaco. Cerca de 30% apresenta alguma manifestação de comprometimento do coração, com ou sem sintomas clínicos, detectada em bases clínicas e por meio de testes diagnósticos diversos (Junqueira Jr, 2012).…”