Left bundle branch pacing (LBBP) significantly increased X- and Y-axis ΣRWA independent of pacing voltage in both CLBBB and narrow QRS patients. LBBP significantly reduced Z-axis ΣRWA in CLBBB but not in narrow QRS patients.

Experimental model and contact force measurements: We conducted a total of 1200 CF measurements using the RMN system (Stereotaxis, St. Louis, MO, USA), a magnetic-guided 8 Fr RF ablation catheter (THERMOCOOL RMT Catheter, Biosense Webster, Irvine, CA, USA) inserted through a long sheath, and a precision jewelry scale (IKEME, Guangdong, CN). We analyzed the impact of four different magnetic field vectors (transverse, sagittal, caudal, and cranial), field strength (0.1 T and 0.08 T), and the extension of the catheter from the long sheath (three models of extension, with Locus 1 being the least extended and Locus 3 the most extended) on the obtained CF values.