Electrogram and Hemodynamic Characteristics of Adaptive LBBAP in Patients With Heart Failure or Bradycardia

Left bundle branch pacing (LBBP), achieved via trans-septal approach with the pacing tip at the left side of the ventricular septum, has recently initiated and been well practiced in China. LBBP is characterized with relatively ease of implantation (usually \<5 minutes fluoroscopic use time), narrow paced QRS duration (similar to physiological pacing), low and stable pacing threshold (usually around 0.5V @0.5ms, good for device longevity and long-term stability without need of back-up pacing lead), high R wave amplitude for pacing management, and LBBB (left bundle branch block) correction by a low pacing output. LBBAP (left bundle branch area pacing) can generate a relatively narrow QRSd and fast left ventricular activation. As AV interval is an important pacing parameter relevant to cardiac function. This study is to investigate the cardiac electrical and mechanical function during LBBAP with different AV intervals.