BACKGROUND The use of antracycline (ANT) in breast cancer has been associated with adverse cardiac events. Two-dimensional (2D) strain imaging (SI) can provide a more sensitive measure of altered left ventricular (LV) systolic function. We aimed to evaluate the preventive effect of carvedilol administration assessed by SI in a patient with breast cancer treated with ANT. METHODS Patients receiving ANT were randomly assigned to the carvedilol- or placebo-receiving group. Each received an echocardiographic examination with conventional 2D echocardiography, pulsed tissue Doppler, and 2D SI prior to and 6 months post ANT treatment. RESULTS During the 6-month follow-up period there were no patient deaths or interrupted chemotherapy treatments due to doxorubicin-induced cardiotoxicity. Both left ventricular ejection fraction (LVEF) and fractional shortening (FS) were within normal limits for all patients before and after ANT therapy. EF, FS and LV dimensions were measured using M-mode echocardiography and found to be similar in both groups before and after ANT therapy. The mean EF, FS, and LV echocardiograph baseline and control dimensions were similar in both groups after 6 months. Though baseline SI parameters were similar between the groups, there was a significant decrease in LV basal septal and basal lateral peak systolic strain in the control group compared to the carvedilol group. CONCLUSIONS These results indicate that carvedilol has a protective effect against the cardiotoxicity induced by ANT.