Assessment of speckle tracking strain predictive value for myocardial fibrosis in subjects with Chagas disease

BACKGROUND: One of the most challenging issues of chronic Chagas disease is to provide earlier detection of heart involvement. Two-dimensional speckle tracking (2-D ST) echocardiography, a new imaging modality with useful applications in several cardiac diseases, has been validated for subjects with myocardial infarction against cardiac magnetic resonance (CMR). Here we hypothesize that the longitudinal global strain (LGS) has an incremental value to ejection fraction for predicting myocardial fibrosis in subjects with Chagas disease. METHODS: This observational study comprised 58 subjects with Chagas disease, confirmed by two positive serologic tests. All subjects underwent conventional Doppler echocardiogram plus speckle tracking strain, and cardiac magnetic resonance. RESULTS: The ROC curve analysis revealed that both LGS (area under the curve: 0.78, p = 0.001) and ejection fraction (area under the curve: 0.82, p < 0.001) were significant predictors of myocardial fibrosis. Regarding the percentage of fibrosis, a high correlation was observed with both ejection fraction assessed by echocardiography (r = 0.70, p < 0.001) and LGS (r = 0.64, p < 0.001). However, when adjusted through multiple linear regression, the LGS lost statistical significance as a predictor of myocardial fibrosis (p = 0.111). CONCLUSIONS: LGS has no incremental value to conventional ejection fraction measurement in the prediction of myocardial fibrosis in subjects with Chagas disease.