Radionuclide angiographic evidence for early predominant right ventricular involvement in patients with Chagas' disease.

Radionuclide angiography was used to study biventricular function in 11 noncardiac (group 1) and eight chronic cardiac chagasic patients (group 2). Results in chagasic patients were compared to those obtained in 10 normal subjects. Global ejection fraction and the standard deviation of peak (SDP) phase histogram were determined for each ventricle and qualitative evaluation of regional wall motion in both anterior and left anterior oblique projections was performed. Left ventricular dysfunction was markedly predominant in group 2, mean +/- SD ejection fraction 39.7 +/- 13.1% and SDP 29.8 +/- 15.6 degrees, as compared to group 1, in which these values were 56.7 +/- 9.9% (P less than 0.01) and 18.3 +/- 7.1 degrees (P less than 0.05), respectively. In contrast, severe right ventricular impairment was found equally in both groups: ejection fraction averaged 31.8 +/- 12.7 and 31.0 +/- 9.1%, and the mean SDP was 29.3 +/- 8.6 and 23.7 +/- 6.7 degrees, in groups 2 and 1, respectively. The qualitative analysis of segmental wall motion also showed apical and/or free-wall right dysynergy in all patients of group 1, while the same abnormalities were detected in six out of eight patients in group 2. These findings indicate that severe functional impairment of right ventricular performance is by far the most significant abnormality detected by radionuclide angiography in chagasic patients who are asymptomatic and have no other clinical sign of heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)