Impaired heart rate variability in patients with chronic Chagas' disease.

Spectral analysis of heart rate variability was used to investigate the possible alteration in sympathovagal control of heart rate in patients with Chagas' disease. The study included 31 subjects, divided into three groups: controls, Chagas' 1 (subjects with only positive serology for Chagas' disease) and Chagas' 2 (subjects with positive serology and electrocardiographic abnormalities that are usually found in this disease). The subjects were studied during rest, while standing, and during handgrip exercise. With this approach, the low frequency (approximately 0.1 Hz) spectral component of R-R interval variability is considered to be a marker primarily of sympathetic activity, whereas the high frequency (approximately 0.25 Hz) component, which is related to respiration, seems mainly to reflect vagal activity. We observed significant (p less than 0.05) differences among the three groups during standing: although in the control subjects the low-frequency component increased (delta = 30 +/- 5 normalized units, nu), there was no increase in Chagas' 1 (delta = -1 +/- 8 nu) and Chagas' 2 (delta = -2 +/- 8 nu) patients. During handgrip exercise, another test that is capable of exciting sympathetic outflow, there was an increase of low frequency only in control subjects. These results confirm the occurrence of quantitative and assessable abnormalities in the neural control of heart rate variability in Argentinian patients with chronic Chagas' disease, even in the absence of heart failure.

[Comparison between immunofluorescent aspects of chronic HBsAG+, HBAG-hepatitis and some cases of chronic toxic-dismetabolic liver diseases]. / Confronto fra gli aspetti all'immunofluorescenza di epatiti croniche HBsAG+, HBsAG- e alcuni casi di epatopatia cronica su base tossico-dismetabolica.

In the study the aspects noticed on hepatic biopsies by I.F. in HBsAg+ and HBsAg- chronic hepatitis and in some cases of hepatitis on dismetabolic basis in Wilson's disease are compared. Great differences occurred between HBsAg+, HBsAg- and the Hepatitis in Wilson disease. In fact in the first case reactivity is often present due to immunological phenomena (presence of IgG immunocomplexes and autoantibodies) while in Wilson's disease these aspects are not found confirming the hypothesis that in the latter case is a question of an exclusively toxic damage.

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

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.