Background Cardiac resynchronization therapy (CRT) with biventricular pacing improves cardiac function,functional capacity and quality of life in selected patients with heart failure.The current study aimed to evaluate the efficacy of the intracardiac electrogram (IEGM)-based optimization method,QuickOptTM,in Chinese patients treated with CRT.Methods Aortic time velocity integrals (AVTI) achieved at the sensed atrioventricular (AV),paced AV and interventricular (VV) interval settings recommended by both QuickOptTM and standard echocardiographic optimization were measured in 101 patients.Consistency and the strength of the relationship between the two timing cycle optimization methods were assessed by intra-class correlation coefficient (ICC).Results The ICC showed good agreement and correlation with what the AVTI achieved at the optimal sensed AV (ICC=0.9683 (0.9535-0.9785)),paced AV (ICC=0.9642 (0.9475-0.9757)) and VV (ICC=0.9730 (0.9602-0.9817)) interval settings determined by the two optimization methods.The average time required by echocardiographic optimization and by QuickOptTM were (78.32±32.40) minutes and (1.98±1.64) minutes respectively (P ＜0.0001).Conclusion The QuickOptTM algorithm provides a quicker,simpler and reliable alternative to the standard method for timing cycle optimization.(ClinicaITrial.gov Reference Number:NCT00918294)