[Impact of atrial high-rate episodes on new onset of atrial fibrillation and all-cause mortality in elderly patients over 90 years old with dual-chamber pacemaker implantation].

<b>Objective:</b> To investigate the impacts of atrial high-rate episodes (AHRE) on the risks of new onset of atrial fibrillation and all-cause mortality in elderly patients over 90 years old after cardiac dual-chamber pacemaker implantation. <b>Methods:</b> This study was a retrospective study. Patients aged 90 years and above who were implanted with cardiac dual-chamber pacemakers and followed up in the People's Liberation Army General Hospital from January 2017 to June 2022 were enrolled and divided into AHRE≥6 h group and AHRE<6 h group according to the onset time of AHRE. The primary endpoint was new onset of atrial fibrillation, and the secondary endpoints were all-cause mortality and cardiovascular mortality. Kaplan-Meier survival curve was poltted, and log-rank test was used to compare the differences in the incidence of new onset of atrial fibrillation, all-cause death and cardiovascular death between AHRE≥6 h and AHRE<6 h groups. Multivariate Cox survival analysis was used to investigate the factors affecting new onset of atrial fibrillation, all-cause death and cardiovascular death in elderly patients aged 90 years and above with dual-chamber pacemaker implantation. <b>Results:</b> A total of 169 patients were enrolled, aged (93.95±3.28) years, including 18 females (11%). The median follow-up time was 28.9 months. There were 87 and 82 patients in AHRE≥6 h group and AHRE<6 h group, respectively. Kaplan-Meier survival curve analysis showed that the incidence of new onset of atrial fibrillation (log-rank <i>P</i><0.001), all-cause death (log-rank <i>P</i>=0.004) and cardiovascular death (log-rank <i>P</i>=0.026) in AHRE≥6 h group was significantly higher than that in AHRE<6 h group.After adjusting for traditional risk factors, multivariate Cox survival analysis showed that AHRE≥6 h was an independent risk factor for new onset of atrial fibrillation (<i>HR</i>=4.046, 95%<i>CI</i> 2.402-6.814, <i>P</i><0.001) and all-cause mortality (<i>HR</i>=1.668, 95%<i>CI</i> 1.119-2.487, <i>P</i>=0.012) in elderly patients over 90 years old with cardiac dual-chamber pacemaker implantation. However, AHRE≥6 h had no effect on cardiovascular mortality (<i>P</i>>0.05). Anemia (<i>HR</i>=3.098, 95%<i>CI</i> 1.342-7.153, <i>P</i>=0.008) and heart failure with reduced ejection fraction (<i>HR</i>=3.028, 95%<i>CI</i> 1.181-7.763, <i>P</i>=0.021) were both independently associated with cardiovascular mortality. <b>Conclusions:</b> AHRE is common in cardiac dual-chamber pacemakers recipients aged 90 years and above, and AHRE≥6 h can be used as a predictor of new onset of atrial fibrillation or all-cause mortality in these patients.