Objective This experiment compared the changes of electrocardiogram（ECG） in patients with malignant tumors caused by paclitaxel chemotherapy

to assess the toxic effects of cardiac electrophysiological activities caused by the clinical commonly used chemotherapy for patients

provide the basis for the safety of clinical use. Methods One hundred and eighty patients with malignant tumor accepting chemotherapy was enrolled. We investigated the heart rhythm

the voltage of QRS wave

the change of ST-T

QT interval and heart rate variability（HRV） by using 12-lead ECG and 24 hours dynamic electrocardiogram before chemotherapy

after three-day chemotherapy

after one-week chemotherapy

after one-month chemotherapy.Results The incidence of abnormal ECGs after one-week chemotherapy and after one-month chemotherapy was lower than that after three-day chemotherapy（p<0.05）. After three-day chemotherapy

the incidence of abnormal ECGs in the group aged over 60 years（n=64） was higher than that in the group aged less than 35 years（n=11） and the group aged between 35 and 60 years（n=105）（p<0.05）. Comparison between the two groups in HRV: SDNN

SDANN

RMSSD

pNN50 of the patients with malignant tumor were all reduced after the chemotherapy（p<0.01）. Conclusions The cardiac electrical activity injury caused by paclitaxel chemotherapy for patients with malignant tumors is related to the time and age.