Use of isometric exercise to demonstrate cardiac parasympathetic impairment in the digestive form of Chagas' disease

Standardized handgrip at 100% of maximal voluntary capacity was used to study heart rate responses to ismetric exercise in patients with the digestive form of Chagas" disease. The chronotropic responses of the group were significantly lower (P < 0.001) than tyhose exhibited by control subjects, and comparable to those observed in a group of cardiac chagasic patient. these results show that severe impairment of autonomic control of the heart may occur in chagasic patients apparently having only digestive tract involvement