Background: Chemotherapy for breast cancer is associated with serious cardiovascular complications such as heart failure. The left ventricular ejection fraction is the main parameter used to assess systolic function in these patients. However, the occurrence of diastolic dysfunction may precede that of systolic dysfunction.Objectives: To evaluate left ventricle diastolic and systolic functions in women with breast cancer undergoing chemotherapy using anthracyclines.Methods: This observational, longitudinal, analytical, and prospective study included 62 women with breast cancer aged 21-75 years old who underwent echocardiography at baseline and after three months of treatment. Diastolic function parameters were evaluated, and the patients were classified as diastolic dysfunction type 1, 2, or 3. Systolic dysfunction was defined as a left ventricular ejection fraction ≤ 53%.Results: After three months of treatment, 35 patients (56.4%) had type 1 diastolic dysfunction, while one (1.6%) had type 2. Diastolic dysfunction was identified in 26 patients at baseline and developed in 10 patients during treatment. Diastolic function parameters, E wave velocity, and E/A ratio decreased significantly (p < 0.05) with chemotherapy; however, the others showed no significant variations. Only three patients had systolic dysfunction, but there was a greater reduction in left ventricular ejection fraction in the group that developed diastolic dysfunction during treatment versus the group with diastolic dysfunction at baseline (p = 0.04). Conclusion:Diastolic dysfunction occurs early in women with breast cancer undergoing chemotherapy. Its onset during the course of treatment is associated with a significantly reduced left ventricular ejection fraction.

Although most chemotherapy agents have adverse side effects, the most feared, due to its morbidity and mortality, is cardiotoxicity. Its main etiological agents are anthracyclines and trastuzumab, both of which are widely used in breast cancer treatment. [1][2][3] Several methods have been proposed to diagnose and assess cardiotoxicity secondary to cancer treatment. Currently, determining left ventricular ejection fraction (LVEF) by echocardiography has been recommended. [4][5][6][7][8][9] However, studies have shown that LVEF, despite being a robust predictor of cardiac events in general, has low sensitivity for detecting changes in LV function, 9 with a detectable drop in LVEF occurring only after damage to a large amount of myocardial tissue. 5 Large studies have found myocardial strain to be an ideal parameter of myocardial deformation for early detection of subclinical systolic dysfunction, ie, even before cardiotoxicity is diagnosed through a drop in