Temporal Trends of Cardiac Chambers Function with Trastuzumab in Human Epidermal Growth Factor Receptor II-Positive Breast Cancer Patients

Background: Trastuzumab has substantially improved overall survival and reduced the risk of disease recurrence in patients with human epidermal growth factor receptor type II (HER-II)-positive breast cancer. However, this benefit may be at the increased risk of cardiotoxicity. We aimed to explore the early subclinical left and right ventricular as well as atrial dysfunction, in trastuzumab-treated patients with HER-II-positive breast cancer, using velocity vector imaging. Methods: Echocardiography images were acquired in 50 patients with HER-II-positive breast cancer undergoing trastuzumab therapy. All patients had baseline and 3-6 months and 12-15 months of follow-up echocardiograms after initiation of trastuzumab therapy. Subendocardial borders of all the cardiac chambers were traced from the apical views to obtain volumetric and deformation indices. Results: Mean age was 60 ± 13 years. Left ventricular (LV) ejection fraction as well as conventional indices of right ventricular (RV) function did not change with trastuzumab. The RV peak systolic global longitudinal strain (GLε) significantly decreased (-24.53 ± 6.03 vs. -21.28 ± 5.11 vs. -21.84 ± 5.15, baseline vs. first and second follow-ups, P = 0.01). LV peak systolic GLε was reduced by 1.19 at early follow-up (P < 0.05). Left atrial reservoir and booster pump functions as well as right atrial reservoir function were reduced through follow-up as well. Conclusions: The RV exhibited greater change in strain after trastuzumab treatment when compared to the LV. Atria function was reduced by trastuzumab as well. The repercussion of these findings and their potential implication will warrant further study.