Stress Echocardiographic Dyssinchrony, Ventricular Myocardial Longitudinal Strain in Chagas Cardiomyopathy Patients: Prognostic Phenotypes Beyond Ejection Fraction

Left ventricular (LV) myocardial deformation (Strain) study is an echocardiographic modality capable of identifying systolic dysfunction even before the drop in ejection fraction (EF).^– Strain can be performed in the longitudinal, radial, and circumferential planes, as well as in their combination, bringing new physiological cardiac parameters such as twist, torsion, and area strain. LV longitudinal axis strain is the cardiac deformation parameter with the most robust scientific evidence and the most relevant use in clinical practice.^– Cardiac resynchronization therapy (CRT) is a therapeutic option already consolidated in international guidelines and promotes a significant reduction in morbidity and mortality, as demonstrated by landmark studies such as MADIT-CRT and CARE-HF.^,, It is recommended as a class I treatment for patients with dilated cardiomyopathy, symptomatic, under optimized clinical treatment, electrocardiogram with left bundle branch block (LBBB) pattern, QRS duration ≥ 150 ms, and LV ejection fraction below 35%.

The analysis of cardiac dyssynchrony can be performed using multiple echocardiographic techniques, including M-mode, conventional Doppler, tissue Doppler, three-dimensional echocardiography, and even ventricular strain analysis.^-,,- The observation of specific patterns of cardiac motion and mechanics, such as apical rocking and septal flash, has been described as important parameters for determining a positive response to CRT in patients with advanced heart failure.^,

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