Determinants of Functional Capacity in Patients with Chagas Disease.

Background: Chagas disease leads to reduced functional capacity. However, the stage at which functional impairment is detectable remains unclear.

Objectives: The present study was addressed to compare the functional capacity of patients at different stages of Chagas disease and healthy individuals and to verify the determinants of peak oxygen uptake (VO2peak).

Methods: In a cross-sectional study, 160 individuals were selected, 35 healthy and 125 with Chagas disease. In the Chagasic group, 61 (49%) were in the indeterminate form of the disease, 45 (36%) with Chagas cardiomyopathy (ChC) and preserved cardiac function and 19 (15%) with cardiac dysfunction and dilated ChC. The data were analyzed using univariate and multivariate regression analysis. Statistical significance was set at 5%.

Results: Patients in the indeterminate form of disease showed similar functional capacity to healthy individuals (p>0.05). Patients with ChC and preserved cardiac function had lower VO2peak than patients in the indeterminate form (p<0.05), but showed similar VO2peak values than dilated ChC (p=0.46). The age, male sex, NYHA functional class, diastolic blood pressure, ratio of the early diastolic transmitral flow velocity to early diastolic mitral annular velocity, left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter were associated with functional capacity. However, only age, male sex, LVEF and NYHA functional class, remained associated with VO2peak in the final model (adjusted R2=0.60).

Conclusion: Patients with ChC had lower functional capacity than patients in the indeterminate form. LVEF, age, male sex and NYHA functional class were determinants with VO2peak in patients with Chagas disease.