Cardiac memory in cardiac resynchronization therapy: A vectorcardiographic comparison of biventricular and left ventricular pacing.

•Cardiac memory is an established electrical phenomenon following altered activation.•It has been reported after resumption of normal conduction in pts undergoing RV pacing and CRT.•We assessed for the first time CM after LV pacing in pts with HF and LBBB using VCG.•Our results provide novel insights into electrical changes induced by pacing in vivo.•CM in LV pacing resulted as increase of T vector magnitude, no direction change.