Identifying non-responders to cardiac resynchronization therapy in the non-left bundle branch block.

Background: Non-response to cardiac resynchronization therapy (CRT) is an important issue in the treatment of heart failure with reduced ejection fraction (HFrEF) and non-left bundle branch block (LBBB). Electrocardiogram-gated myocardial perfusion single-photon emission computed tomography imaging (G-MPI SPECT) is typically used to assess left ventricular (LV) dyssynchrony. This study aimed to determine whether G-MPI parameters are associated with non-responsiveness to CRT.