Recurrent syncope in patients with a pacemaker and bradyarrhythmia.

Background. Pacemakers are used to treat syncope in patients with bradyarrhythmia; however, the risk of recurrent syncope has only been investigated in few and smaller studies. Objective. The aim of this study was to investigate the risk of recurrent syncope after pacemaker implantation in patients with bradyarrhythmia and prior syncope. Methods. This retrospective, population-based cohort study included patients with a prior syncope and implantation of a pacemaker using data from the Danish nationwide registers from 1996 to 2017. Cumulative incidence and cox regression was used to estimate the 5-year incidence and the risk of recurrent syncope, respectively. Results. In total, 11,126 patients (median age: 78 years, interquartile range: 69-85, 56% male) were included and the 5-year cumulative incidence of recurrent syncope was 19.6% (95% confidence interval (CI): 18.8-20.3%). Sinus node dysfunction (hazard ratio [HR]: 1.29, 95%CI: 1.17-1.42) and unspecified type of bradyarrhythmia (HR: 1.32, 95%CI: 1.15-1.52) were associated with an increased risk of syncope compared to advanced atrioventricular (AV) block. Male sex (HR: 1.22, 95%CI: 1.22-1.34), cerebrovascular disease (HR: 1.17, 95%CI: 1.05-1.30), and prior number of syncopes were significantly associated with a higher HR of recurrent syncope. Conclusion. Almost one-in-five patients with bradyarrhythmia and prior syncope who had a pacemaker implanted had a recurrent syncope within five years. A higher risk of syncope was observed among patients with sinus node dysfunction and unspecified type of bradyarrhythmia compared to AV block. Male sex, cerebrovascular disease, and prior number of syncopes were associated risk factors of recurrent syncope.