LBBAP implantation procedure
Details of the LBBAP procedure have been described before[18]. The ventricular pacing lead (Medtronic Inc. 3830 lead) was introduced via a 7-Fr guiding sheath (Medtronic Inc. C315 HIS). After mapping the His-potential, the 3830 lead was advanced 15-20 mm towards the cardiac apex. The lead was screwed into the interventricular septum and finally fixed at the left bundle branch area when there was a right bundle branch block (RBBB) pattern in the V1 lead. Successful LBBAP is defined[19] as the capture of the subendocardial area on the left side of the interventricular septum, with or without simultaneous conduction system capture, and includes left bundle branch pacing (LBBP), left fascicular pacing (LFP), and left ventricular septal pacing (LVSP). The lower rate of the pacemaker was set at 60, 70, or 75 bpm based on the condition of the patients, and was not changed during follow-up.