摘要目的:初步探讨无导线起搏器植入后远期阈值升高的风险因素，并分析植入时电学参数是否对远期阈值改变有预测意义。方法:本研究为回顾性、队列研究。选取2019年12月至2021年12月在中南大学湘雅二医院接受无导线起搏器（Micra）植入的患者，收集患者的年龄、性别、既往疾病史，植入无导线起搏器术中及术后相关电学参数。根据术后12个月时测定的阈值，将患者分为阈值升高组与阈值稳定组。采用单因素回归分析探究无导线起搏器植入后阈值升高的相关风险因素。绘制受试者工作特征（ROC曲线）并根据曲线下面积（AUC）分析术中阻抗对起搏阈值变化趋势的预测价值。结果:共入选75例患者，年龄（69.1±10.9）岁，其中男44例。无导线起搏器植入时，阈值稳定组术中阻抗[（832.1±192.8）?Ω对（678.4±88.0） Ω， P<0.001]和阈值[（0.7±0.2）V/0.24 ms对（0.5±0.1）V/0.24 ms， P<0.001]高于阈值升高组，感知低于阈值升高组，差异无统计学意义[（7.3±3.8）?mV对（8.3±4.1）mV， P=0.291]。随访期间，阈值稳定组阻抗[（694.4±123.6） Ω对（580.8±97.8） Ω， P=0.790]、感知[（10.5±4.3）mV对（10.7±3.7） mV， P=0.436]与阈值升高组差异无统计学意义，阈值低于阈值升高组[（0.6±0.2） V/0.24 ms对（0.7±0.2） V/0.24 ms， P=0.008]。单因素回归分析显示植入时阻抗较低是远期阈值升高的预测因素（ OR=0.989，95% CI 0.983~0.995， P<0.001）。ROC曲线显示，术后阻抗≥745?Ω时，远期阈值升高的风险较低（AUC=0.808，95% CI 0.707~0.910， P<0.001），敏感度为72%，特异度为89%。 结论:无导线起搏器植入时阻抗较低对远期阈值升高有预测价值，术后阻抗≥745?Ω时，提示远期阈值升高的风险较低。

abstractsObjective:To analyze the risk factors associated with the increase in long-term threshold after implantation of leadless pacemakers, and explore the predictive value of the pacing parameters during leadless pacemaker implantation on the trend of changes of long-term pacing threshold.Methods:This is a retrospective cohort study. The patients underwent the leadless pacemaker at Second Xiangya Hospital of Central South University from December 2019 to December 2021 were enrolled. The age, sex, medical history and the pacing parameters (threshold, amplitude, impedance) of procedure and 12 months post-implant were collected. According to the threshold measured at 12 months after implantation, the patients were divided into the elevated threshold group and the threshold stabilization group. Univariable Logistic analysis was used to analyze the risk factors associated with the increase in long-term threshold after implantation of leadless pacemakers. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used to analyze the value of the impedance during implantation on predicting the trend of changes of pacing threshold post implantation.Results:A total of 75 patients, mean age (69.1±10.9) years, 44 males, were included. The average impedance of the threshold stabilization group during procedure was higher than that in the elevated thresholds group [ (832.1±192.8) Ω vs. (678.4±88.0) Ω, P<0.001] , and the threshold in the threshold stabilization group was higher than that in the elevated thresholds group [ (0.7±0.2) V/0.24 ms vs. (0.5±0.1) V/0.24 ms, P<0.001] .There were no significant differences in average sense between the stable threshold group and the elevated threshold group [ (7.3±3.8) mV vs. (8.3±4.1) mV, P=0.291] . During the follow-up period, there were no significant differences in impedance [ (694.4±123.6) Ω vs. (580.8±97.8) Ω, P=0.790] and sense [ (10.5±4.3) mV vs. (10.7±3.7) mV, P=0.436] between the threshold stabilization group and the elevated threshold group. The threshold of the threshold stabilization group was lower than that of the elevated thresholds group [ (0.6±0.2) V/0.24 ms vs. (0.7±0.2) V/0.24 ms, P=0.008] .Univariable Logistic analysis showed that low impedance at implantation was a predictor of threshold elevation at long-term follow-up after leadless pacemakers implantation ( OR=0.989, 95% CI 0.983-0.995, P<0.001) . According to the analysis of the ROC curve, the impedance during procedure≥745?Ω was associated with a lower risk of long-term threshold elevation (AUC=0.808, 95% CI 0.707-0.910, P<0.001) . The sensitivity was 72%, and the specificity was 89%. Conclusion:Low impedance during procedure has predictive value for the long-term trend threshold increase. Impedance≥745?Ω during procedure could predict a lower risk of long-term threshold elevation.