Background Cardiac resynchronization therapy (CRT) improves mortality of heart failure patients with QRS duration≥120 ms, especially in left branch bundle block (LBBB) setting.However, less than 10％ of patients with heart failure(HF) and abnormal ventricular conduction were subjected to right branch bundle block (RBBB).Limited data are available in this particular population, and relevant research results are inconsistent.The study evaluates the effect of CRT in HF patients with RBBB, who presented major inter-and intra-ventricular asynchrony assessed by echocardiography with tissue Doppler imaging (TDI).