Table 1. Characterization of the subjects included in the study.

Clinical characterization	Subjects numbers	Age in years (mean ± SD)	Sex males (%)
Seropositive for T. cruzi-specific antibodies
Chagasic, clinically-asymptomatic	n = 25	49.8 ± 9.2	14 (46.6%)
Chagasic, clinically-symptomatic	n = 28	53.1 ± 10.6	16 (53.3%)
Seronegative for T. cruzi-specific antibodies
Normal healthy, no disease	n = 30	39 ± 16.2	15 (50%)

Subjects were screened for T. cruzi-specific antibodies by Wiener Chagatest-ELISA and Wiener Chagastest-HAI kits. Clinical exam included physical exam, electrocardiography and echocardiography. Seropositive individuals with no to minor echocardiography abnormalities, no left ventricular dilatations, preserved systolic function (ejection fraction: 55–70%) were considered clinically-asymptomatic. Seropositive individuals with varying degree of heart involvement evidenced by systolic dysfunction (ejection fraction: <55%), left ventricular dilatation (diastolic diameter ≥57 mm), and/or potential signs of congestive heart failure were classified as clinically-symptomatic.