Interesting electrophysiological phenomenon during positioning of the lead deep inside the septum.

Left bundle branch pacing (LBBP) is a developing physiological pacing technique. Wu et al. proposed that direct LBB capture could be confirmed by recording retrograde His potential (PoReHis ) and mapping of the left conduction system potential. The transventricular-septal electrophysiological phenomena deserve further study. Here, we used a continuous uninterrupted pacing technique to confirm the LBB capture by dynamically observing changes in PoReHis and stimulus to left ventricular activation time.