RESUMO
BACKGROUND: Although there is anatomopathologic evidence of atrial involvement in Chagas cardiomyopathy (CCM), the impact in left atrial (LA) function is unknown. The aim of this study was to evaluate LA function in patients with CCM with real-time three-dimensional echocardiography (RT3DE) and to compare it with patients with idiopathic dilated cardiomyopathy (DCM). METHODS: A total of 30 patients with CCM, 30 patients with DCM, and 20 normal subjects used as the control group were studied. With the use of RT3DE, we measured LA maximum (maxLAV), minimum, and pre-atrial contraction volumes and calculated total and active LA emptying fractions. RESULTS: Left ventricular ejection fraction and mitral regurgitation were similar in both groups. MaxLAV/m(2) was larger in the CCM group than in the DCM group (76.9 ± 21.9 mL vs. 59.1 ± 26.0 mL; P < .01), and both were significantly larger than in the control group (P < .01). Total LA emptying fraction was lower in the CCM group than in the DCM group (0.30 ± 0.10 vs. 0.40 ± 0.12; P < .01), and both were lower than in the control group (P = .01). Active LA emptying fraction was also lower in the CCM group than in the DCM group (0.22 ± 0.09 vs. 0.28 ± 0.11; P < .01), and both were lower than in the control group (P = .01). The E/e' ratio was higher in the CCM group than in the DCM group (21 ± 10 vs. 15 ± 6; P < .01), and both were greater than in the control group (P < .01). In a multiple regression model, the E/e' ratio was the only independent predictor of a worsening active LA emptying fraction. CONCLUSION: LA function is more compromised in patients with CCM than in patients with DCM. This finding indicates a more diffuse and severe myocardial impairment in Chagas disease that is probably related to increased left ventricular filling pressures and atrial myopathy.
