2.2 Participants recruitment
Consecutive patients who met the inclusion criteria were enrolled between February 9, 2018 and October 16, 2020. The inclusion criteria should meet the following: (1) an ECG showed a morphology of typical complete RBBB (cRBBB). The diagnostic criteria of cRBBB is as following : the QRS duration >0.12 sec, rSR’ or RR’ pattern in leads V1 and/or V2, wide and slurred S wave in leads V6 and I (S>R duration or S wave duration ≥ 0.06 sec) 6. (2) patients were indicated for pacing therapy, (3) the LBB or LBB area was captured. Patients with any one of the following conditions were excluded: (1) incomplete RBBB (iRBBB), defined as the QRS duration in 0.10-0.12 sec and rsr’ pattern in leads V1 and/or V2 6. (2) right ventricular septal pacing (RVSP), (3) left bundle branch block (LBBB), including complete LBBB, incomplete LBBB, left anterior fascicular block (LAFB), and left posterior fascicular block (LPFB), (4) patients declining guideline-indicated pacing therapy. The study was approved by the Ethics Committee of Xiamen Cardiovascular Hospital, Xiamen University, and the informed consent of each patient was obtained. The study was conducted in accordance with the principles of the Declaration of Helsinki.