Left bundle branch pacing (LBBP) is a new physiological pacing technique that provides new options for device treatment in patients with bradycardia and heart failure. Recent data have shown that this method was able to obtain a low and stable threshold compared to His bundle pacing 1. The Wenckebach phenomenon refers to a progressive lengthening of impulse conduction time, followed by a non-conducted impulse or dropped beat. We have observed a progressive prolongation of stimulus-ventricular (S-V) interval that was followed by ventricular depolarization in an intracardiac electrogram (EGM) of a patient. This process is defined as the Jiang’s phenomenon, which is different from the Wenckebach phenomenon. Some electrophysiological phenomena were also observed with the guidance of John Jiang’s connecting cable in LBBP 2. Unlike a traditional connecting cable, which has to be disconnected while the pacing lead is screwed into the septum, John Jiang’s connecting cable allows for simultaneous monitoring and recording of electrocardiogram (ECG) and intracardiac EGM during lead deployment.