Do all intra-ventricular conduction defect ECG patterns respond equally to CRT?

Purpose: Response to cardiac resynchronization therapy (CRT) is well-established in patients with typical left bundle branch block (LBBB) but modest or even negative in those with intraventricular conduction delay (IVCD). However, IVCD pattern is heterogeneous, and it is possible that QRS patterns may also respond to CRT.

Methods: Consecutive baseline ECGs of 239 patients implanted between 2007 and 2010 with CRT were analyzed.