Inclusion Criteria:  Aged 18 to 80 years old; Symptomatic sinus bradycardia; Not meet the class I indications for pacemaker implantation.  Exclusion Criteria:  Structural heart disease, heart surgery history; Drug-induced SB, sinus pause >2.0 s, positive atropine test, corrected sinus node recovery time (cSNRT) >525 ms; Any atrial or ventricular arrhythmia, or a history of ablation procedures to treat atrial tachyarrhythmias; With Significant congenital heart disease, ejection fraction was <40% measured by echocardiography; Allergic to contrast media; Contraindication to anticoagulation medications; Severe pulmonary disease e.g. restrictive pulmonary disease, chronic obstructive disease (COPD);  9. Poor general health; 10.Life expectancy less than 6 months.