Effects of sympathetic activation on heart rate variability in Chagas' patients.

ABSTRACT

To assess the alterations present in neural control of heart rate in patients with signs of Chagas' disease we studied the spectral components of heart rate variability in 10 Chagas' patients, without cardiac failure, and in 10 control subjects during supine and standing position. Chagas' patients during standing did not present the changes in the spectral components of heart rate variability which normally accompany sympathetic activation and vagal withdrawal.