Transthoracic echocardiography (TEE) plays a major role in the baseline assessment and follow-up of cardio-oncology patients. While left ventricular ejection fraction (LVEF) still has its place in cardiac monitoring, new modalities like myocardial deformation imaging with speckle tracking strain analysis has been validated for early detection of subclinical LV dysfunction.

We conducted a longitudinal prospective study including all the breast cancer patients treated with anthracyclines and trastuzumab from January 2017 to March 2022. All patients underwent baseline TEE, and were followed-up every 3months after that, with GLS assessment whenever it was possible. We evaluated the frequency of GLS drop and its correlation to LVEF reduction.

Out of a total of 1583 patients, 677 had available LV GLS assessment. Among them, 83 (12.3%) decreased their GLS during follow-up, 67% of which had no concomitant drop in LVEF. In these patients, impaired LV GLS values were noted at 3months after chemotherapy and at 6, and 12months compared with baseline (−22.3±1.8% at baseline, −18.1±2.3% at 3months, −17.7±2.1% at 6months, and −16.9±2.1% at 12months). LV GLS at 3months was strongly correlated to cardiotoxicity (LVEF<50%) at 12months (P<0.05). A cut-off LV GLS value of −16.9% was then retained to identify LVEF alteration at the end of follow-up. Finally, our study found that GLS at 3months and 6months had a prognostic value, since the lower GLS was, the poorest the patient's clinical outcome was, with further development of symptomatic heart failure.

Our study demonstrates that myocardial deformation analysis enables detection of early and progressive subclinical cardiac dysfunction, and GLS at 3months was positively correlated to LVEF drop at 12months.