Objective To investigate the changes of serum cytokines in chronic heart failure (CHF) patients who received cardiac resynchronization therapy for 1 and 3 months and its relationship with left ventricular ejection fraction (LVEF).Methods Thirty CHF patients with New York Heart Association (NYHA) classⅢor Ⅳwere selected. Fifteen patients received biventricular pacing therapy (CRT group) and the other 15 patients received optimal medical therapy (control group). The LVEF and serum levels of TNF-α and IL-6 were determined before treatment,at 1,3 months after treatment respectively.Results The serum TNF-α and IL-6 concentrations were decreased significantly after 3 months of CRT treatment,and LVEF was improved remarkably after 1 and 3 months of CRT treatment. The serum cytokines (TNF-α and IL-6) level had a significant negative correlation with LVEF. Conclusion After 3 months of CRT treatment,the heart function is improved,and serum cytokines(TNF-α,IL-6) concentrations are decreased. It indicates that serum level of TNF-α and IL-6 may have predictive value for the heart function of patients with CHF.