[Temporal analysis of cardiac frequency variability in basal condition in elderly chagasic subjects in indeterminate form in endemic área]. / Análise temporal da variabilidade da freqüência cardíaca no estado basal em idosos chagásicos na forma indeterminada em área endêmica.

With the aim of evaluating the cardiac autonomic function in elderly chagasic patients living in an endemic area, we evaluated, by using computadorized heart rate variability, 28 elderly chagasic with the indeterminate form, 28 elderly non chagasic and 28 young healthy control. In all patients we performed conventional electrocardiogram, radiological investigation of thorax, and with contrast of esophagus and colons and echodopplercardiogram. Non chagasic patients did not perform only the exams with contrast. The systolic ventricular function was preserved in all subjects. There was no statistically significant difference between the groups with regard to mean duration of RR intervals. Considering the variance, standard deviation, variation coefficient and pNN50 there was statistically significant difference between the young and elderly groups but no difference was found when the analysis was performed in each one separately for these temporal indexes. We conclude that, in basal condition, the groups of elderly chagasic and no chagasic subjects did not differ as much as the cardiac autonomic modulation in time domain.