In the increased pacing threshold (IPT) group, the pacing threshold increased by ≥0.5 V/0.24 msec within 1 month after implantation, and in the stable pacing threshold (SPT) group, the pacing threshold increased by <0.5 V/0.24 msec within 1 month after implantation. Abbreviations: AF: atrial fibrillation; BNP: B-type natriuretic peptide; CAVB: complete atrial ventricular block; DM: diabetes mellitus; HD: hemodialysis; HT: hypertension; IHD: ischemic heart disease; LVEF: left ventricular ejection fraction; SSS: sick sinus syndrome; Type II AVB: type second-degree atrioventricular block. *P-values<0.05 were considered statistically significant.