Echocardiographic Strain Analysis Compared With Assessment of Fibrosis by Cardiac Magnetic Resonance in the Evaluation of Chagas Cardiomyopathy.

AIM: Chagas cardiomyopathy (CC) is characterized by progressive myocardial fibrosis, contractile dysfunction, and structural remodeling. Strain imaging (SI) holds promise for detecting early myocardial impairment, but its utility in tracking CC progression remains unclear. This study evaluated SI's clinical utility across the CC spectrum. METHODS AND RESULTS: In this cross-sectional study, 79 adults with serologically confirmed Chagas disease underwent myocardial strain assessment using equipment from General Electric (GE) or Philips (PH). Strain parameters, including global longitudinal strain (GLS), and segmental longitudinal strain (SLS), were analyzed across four CC stages (A, B1, B2, and C), stratified by fibrosis severity via late gadolinium enhancement (LGE) on cardiac magnetic resonance. Spearman coefficients assessed correlations between strain and fibrosis burden. Lin's concordance index evaluated inter-vendor agreement. Diagnostic performance for fibrosis detection was quantified using area under the receiver operating characteristic curve (AUC), with strain abnormalities defined by ROC-derived median cut-offs. GLS declined progressively with advancing CC stage across both vendors, though correlations with fibrosis percentage were weak (ρ < 0.30). SLS abnormalities were present in Stage A patients despite absence of LGE-detected fibrosis. SLS showed moderate accuracy in localizing, but not quantifying, fibrosis (mean AUC: 0.72 ± 0.11). Inter-vendor concordance was limited for GLS (Lin's index: 0.80) and SLS (range: 0.20-0.70). CONCLUSIONS: SI reveals early myocardial dysfunction in Chagas patients, even in the absence of detectable fibrosis, suggesting a subclinical continuum of disease. However, the modest correlation with fibrosis burden and substantial inter-vendor variability underscore the need for vendor-specific calibration and caution in clinical interpretation.