Chagas' heart disease as an experimental model for studies of cardiac autonomic function in man.

Patients presented here include apparently healthy persons who had diagnostic evidence of chronic cardiac Chagas' disease in the form of a positive complement-fixation test and an abnormal electrocardiogram. They had never been in heart failure. All were examined for autonomic cardiac function. Normal persons served as controls. Patients with Chagas' disease with sole involvement of hollow viscera were also included. In patients with cardiac Chagas' disease, failure of the heart rate to increase after administration of atropine and greatly reduced reflex changes in cardiac rate are believed to be a functional disorder related to degeneration of the neuronal supply to the sinoatrial region of the heart. It is concluded that Chagas' disease is a model of spontaneous denervation of the heart which may be used for the assessment of autonomic control of cardiac function in man.