Increased base rate of atrial pacing for prevention of atrial fibrillation after implantation of a dual-chamber pacemaker: insights from the Atrial Overdrive Pacing Study.

AIMS: Different pacing sites and various algorithms have been utilized to prevent atrial fibrillation (AF) in pacemaker recipients. However, the optimal pacing rate settings have not yet been established. In this randomized, prospective, multicentre, single-blinded, cross over study, rate-adaptive pacing at a high base rate (BR) in patients, age 60 years or above, or a history of paroxysmal AF, who underwent dual-chamber (DDD) pacemaker implantation for standard pacing indications, was evaluated for prevention of AF. METHODS AND RESULTS: In the study cohort of 145 patients implanted with DDD pacemakers with a programmable rest rate (RR) feature, the BR/RR settings were sequentially but randomly adjusted as follows: 60 bpm/Off for the baseline quarter (initial 3 months) and then to either 'A-B-C' or 'C-B-A' settings (A = 70/65 bpm, B = 70/Off, C = 80/65 bpm) for the subsequent quarters each of 3 months duration. Data on automatic mode switch episodes, device diagnostics, and a questionnaire evaluating pacemaker awareness and palpitations were collected. Ninety-nine patients, mean age 77 +/- 10 years, who completed the study protocol and followed for 12 months did not show significant differences in the number of mode switch episodes between any settings used. The percentage of atrial pacing was lower during baseline pacing compared to settings A, B, and C (P < 0.0001). Setting C produced a higher percentage of atrial pacing than A and B (P < 0.01). Although a higher percentage of atrial pacing correlated with a lower incidence of mode switch episodes, there was no statistically significant difference in the number of mode switch episodes between settings A, B, and C. There were no significant differences in the questionnaire scores relating to pacemaker awareness or palpitation. CONCLUSION: Overdrive single-site pacing in the right atrium achieved by programming analysed settings in the present study did not reduce AF as assessed by mode switch episodes. Additionally, no change in the symptoms of arrhythmia or awareness of pacing was seen.     

Malignant ventricular tachycardia and cardiac arrest induced by a micra™ leadless pacemaker

Leadless pacemaker implantation represents an important advancement in the treatment of bradycardia, and occupy an increasing part in the clinic. Major adverse effects associated with leadless pacemaker implantation are rare, with a serious complication being pericardial effusion. We present a case of a patient who had a leadless pacemaker implanted, which induced ventricular tachycardia and cardiac arrest during hospitalization.     

无导线起搏器置入术中阻抗对起搏阈值变化趋势预测价值初探

目的初步探讨无导线起搏器Micra置入术中释放即刻阻抗对起搏阈值变化趋势的预测价值。方法本研究为回顾性、横断面研究, 选取2019年12月—2020年8月在中南大学湘雅二医院接受无导线起搏器Micra置入的患者, 收集患者基本临床资料、无导线起搏器置入术中电学参数, 将阻抗和起搏阈值分为释放即刻、释放后5～10 min和牵拉试验后3组。采用重复测量方差分析统计对比3组电学参数, 绘制受试者工作特征(ROC)曲线并根据曲线下面积(AUC)分析释放即刻阻抗对起搏阈值变化趋势的预测价值。结果共纳入21例置入Micra无导线起搏器的患者, 男性12例(57%), 年龄(72.2±12.5)岁。21例患者置入术中释放即刻阻抗为(798.1±35.3)Ω, 释放后5～10 min为(800.9±35.6)Ω, 牵拉试验后为(883.6±31.7)Ω, 3组阻抗间的差异无统计学意义(P>0.05)。释放即刻阈值为(0.97±0.11)V/0.24 ms, 释放后5～10 min为(0.95±0.12)V/0.24 ms, 牵拉试验后为(0.59±0.06)V/0.24 ms, 牵拉试验后阈值低...     

Magnetic navigation and voltage mapping guided implantation of a pacemaker atrial lead in a previously unpaceable patient.

We report successful implantation of the atrial pacing lead in a patient in whom such operation had previously failed with the manual approach. Right atrial (RA) electro-anatomical voltage mapping was used to identify an area suitable for pacing and magnetic navigation to allow exhaustive RA exploration leading to successful RA lead screwing.