Chagas' heart disease: evolutive evaluation of electrocardiographic and echocardiographic parameters in patients with the indeterminate form.

OBJECTIVE To identify and associate potential electrocardiographic and echocardiographic changes in patients with the indeterminate form of Chagas' disease during long-term follow-up. METHODS One hundred sixty patients underwent standard electrocardiography and two-dimensional guided M-mode echocardiography for left ventricular ejection fraction determination. Patients were followed up for 98.6+/-30.4 months, undergoing repeat electrocardiographic studies at 6-month intervals and echocardiographic studies at 12-month intervals. RESULTS Based on the electrocardiographic findings, the patients were divided into group I, 125 patients (78.6%) with normal electrocardiograms throughout follow-up, and group II, 34 patients (21.3%) who developed electrocardiographic changes. Group II was further divided into group IIA (9 patients, 5.6%) with permanent electrocardiographic changes, group IIB (14 patients, 8.8%) with transitory electrocardiographic changes, and group IIC (11 patients, 6.9%) with changes appearing only on the final electrocardiogram. Left ventricular ejection fractions remained normal in the entire population studied and did not differ among groups. CONCLUSION The indeterminate form of Chagas' disease clearly represents a benign condition with a favorable long-term prognosis. Although some patients develop electrocardiographic changes, left ventricular systolic function is well preserved.