Beta-adrenergic blockers in chronic systolic heart failure secondary to Chagas' disease

摘要

The pathogenesis of Chagas' disease has been linked to abnormalities of the autonomic nervous system, since the very early descriptions of the disease . Thus, Koberle postulated in the 1950s his very well known neurogenic hypothesis, on the pathogenesis of chronic Chagas' heart disease . According to this hypothesis, the parasite would irreversibly destroy the postganglionic cardiac para-sympathetic neurons during the acute phase of the disease. Sympathetic predominance would follow, exposing the myocardium to the toxic effects of catecholamines. However, Koberle's hypothesis was based on autopsies of patients who had died in advanced stages of the disease (i.e. congestive heart failure). Cardiac neuronal counts in chagasic patients, who died from-non-cardiac causes and had no macroscopic evidence of myocardial damage, were either normal of minunally decreased [3-5]. Moreover, functional tests of autonomic function were normal in asymptomatic patients with no electrocardiographic evidence of heart disease and could also be normal or impaired, in those patients with abnormal electrocardiograms . The results of these functional and morphological studies clearly indicated that, the abnormalities of the parasympathetic nervous system were not homogenous#