［Abstract］　Left bundle branch block(LBBB) is a common complication in patients with heart failure(HF). According to the pathophysiological process, if LBBB develops first and gradually induces left ventricle(LV) remodeling and hemodynamic deterioration, this type of HF is considered as “LBBB inducing HF”; if HF develops first, and then a subsequent complication of LBBB occurs, this type of HF is considered as “HF inducing LBBB”. For the former type of HF patients, after the LV activation sequence corrected by cardiac resynchronization therapy(CRT), the mechanical dyssynchrony and cardiac remodeling can be reversed and the patients will have good response to CRT; while for the latter type of HF patients, even though the activation sequence is corrected by CRT, underlying cardiomyopathy cannot be resolved and therefore it is likely that the patients will not respond to CRT. Cardiac magnetic resonance(CMR) tissue tracking can identify the unique abnormal movement of the septal wall and the preserved systolic function of left ventricular lateral wall in patients with “LBBB inducing HF”, while extensive myocardial dyskinesia can be recognized in patients with “HF inducing LBBB”. For patients with unclear medical history, if the left ventricular end-diastolic lateral wall/septal wall thickness ratio is greater than 0.93 and the left ventricular lateral wall thickening rate is greater than 21%, the patients can be considered as “LBBB inducing HF ”, on the contrary, the patients are considered as “ HF inducing LBBB”. CMR can provide predictive value for CRT response and provide an important basis for clinical selection of HF patients who are suitable for CRT.