ObjectiveTo investigate the effect of anthracycline chemotherapy combined with trastuzumab on leftventricular function in HER2-postive breast cancer patients by three-dimensional speckle tracking echocardiography（3 D-STE）.MethodsSixty-five HER2-postive breast cancer patients treated with AC-D-T chemotherapy with 21 d as a cycle wereenrolled. The cycles of themotherapy were:In the 0 cycle

chemotherapy wasn’t applied after surgery. Epirubicin（Epi）andcyclophosphamide were given in the 1～4 cycle of chemotherapy. Docetaxel and trastuzumab were given in the 5～8 cycle ofchemotherapy. Trastuzumab was only given in the 9 cycle of chemotherapy. At the end of each cycle

the conventionalechocardiographic and 3 D-STE parameters were measured

including the left ventricular end-diastolic diameter（LVDd）

leftventricular end-systolic diameter（LVDs）

interventricular septum diastolic thickness（IVSTd）

posterior wall diastolic thickness（PWTd）

the ratio of transmitral peak early to late diastolic velocity（E/A）

the left ventricular end-diastolic volume（LVEDV）

left ventricular end-systolic volume（LVESV）and LV ejection fraction（LVEF）.3 D-STE parameters including LVEDV

LVESVand LVEF

left ventricle global longitudinal strain（GLS）

globalradial strain（GRS）

global circumferential strain（GCS）andglobal area strain（GAS）.The parameters of each cycle were compared.ResultsThe conventional echcardiographic parametersand 3 D-STE parameters LVEDV

LVESV

LVEF had no significantly difference among all cycles of chemotherapy.The GLSand GAS had significant difference compared between 4～9 cycle and 0 cycle

8～9 cycle

0～3 cycle and 4 cycle

0～4 cycleand 8 cycle

0～7 cycle and 9 cycle of chemotherapy

respectively（all P<0.05）.There were no significant differences of GRS

GCSin all cycles of chemotherapy.Conclusion3 D-STE could sensitively evaluate the effect of AC-D-T chemotherapy on leftventricular function in HER2-postive breast cancer patients.