Background:High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia,and a domestically developed pacemaker will help lower the burden.This study aimed to evaluate the safety and efficacy ofQinming8631 DR (Qinming Medical,Baoji,China),the first domestically developed dual-chamber pacemaker of China,compared with a commercially available pacemaker Talos DR (Biotronik,Berlin,Germany) in Chinese patients.Methods:A prospective randomized trial was conducted at 14 centers in China.Participants were randomized into trial (Qinming8631 DR) and control (Talos DR) groups.Parameters of the pacing systems were collected immediately after device implantation and during follow-ups.The effective pacing rate at 6-month follow-up was recorded as the primary end point.Electrical properties,magnet response,single-and double-pole polarity conversion,rate response function,and adverse events of the pacing system were analyzed.The Cochran-Mantel-Haenszel Chi-square test,paired t-test,and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data.Results:A total of 225 patients with a diagnosis ofbradyarrhythmia and eligible for this study were randomly enrolled into the trial (n =113) and control (n =112) groups.They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity.Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set (81.4％ vs.79.5％,P =0.712 and 95.4％ vs.89.5％,P =0.143,respectively).In both data sets,noninferiority of the trial group was above the predefined noninferiority limit(-9.5％).Conclusions:This study established the noninferiority ofQinming8631 DR to Talos DR.The safety and efficacy ofQinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with cardiac bradyarrhythmia.