Abstract： Background Patients with multivessel coronary artery disease and depressed left ventricular ejection fraction (LVEF)represent a high risk group of patients for coronary revascularization.There are limited data on percutaneous coronary intervention treatment in this population.Methods Among a cohort of 4335 patients with three-vessel disease with or without left main disease undergoing percutaneous coronary intervention,191 patients had LVEF ＜40％ (low ejection fraction (EF)) and 4144 patients had LVEF ＞40％.In-hospital and long-term outcomes were examined according to LVEF.Results The estimated two-year rates of major adverse cardiac events,cardiac death,and myocardial infarction were significantly higher in the low EF group (19.64％ vs.8.73％,Log-rank test:P ＜0.01; 10.30％ vs.1.33％,Log-rank test:P ＜0.01,and 10.32％ vs.2.28％,Log-rank test:P ＜0.01 respectively),but there was no difference in the rates of target vessel revascularization (6.18％ vs.6.11％,Log-rank test:P=0.96).Using the Cox proportional hazard models,LVEF ＜40％ was a significant risk factor for cardiac death,myocardial infarction,and major adverse cardiac events (OR (95％CI):4.779 (2.369-9.637),2.673 (1.353-5.282),and 1.827 (1.187-2.813) respectively),but was not a statistically significant risk factor for target vessel revascularization (OR (95％ CI):1.094 (0.558-2.147)).Conclusion Among patients undergoing percutaneous coronary intervention for multivessel coronary artery disease,left ventricular dysfunction remains associated with further risk of cardiac death in-hospital and during long-term follow-up.