Objective:To investigate the association between pulmonary capillary wedge pressure (PCWP)and clinical outcome of cardiac resynchronization therapy (CRT)in chronic heart failure patients. Methods:Chronic heart failure patients with an indication for CRT were included. We performed right heart catheterization to measure PCWP in those patients one week before they received a CRT device. Patients were stratified into two groups based on their response to CRT:responders and non-responders. Responders were predefined as patients with improvement of left ventricular ejection fraction (LVEF)by 5% or more and improvement by one or more NYHA functional class during 6-month follow-up. Receiver operating characteristic (ROC)curve was used to assess the efficiency of preoperative PCWP in predicting CRT response. Kaplan-Meier survival curve was applied to assess the efficiency of preoperative PCWP in predicting major adverse cardiac events (MACE). Results:Of 35 patients included,24 patients were responders,11 patients were non-responders. The mean PCWP was (11.9 ± 7.0)mmHg and (21.7 ± 9.1)mmHg,respectively. Non-responders had a significantly higher PCWP (P=0.006). When at the optimal cutoff point of 12.0 mmHg,the sensitivity and specificity of preoperative PCWP predicting response to CRT were 90.9% and 58.3%,respectively. Patients with preoperative PCWP 12.0 mmHg or less have better NYHA functional class-smaller left ventricle and lower PCWP after CRT compared with patients with preoperative PCWP 12.0 mmHg or more. Kaplan Meier survival curve demonstrated that compared with patients with preoperative PCWP 12.0 mmHg or less,patients with preoperative PCWP 12.0 mmHg or more had a trend towards being shorter MACE-free survival (P=0.079). Conclusion:Preoperative PCWP is associated with response to CRT. Lower preoperative PCWP may indicate longer MACE-free survival time in CHF patients.