Schuchert A, Ventura R, Meinertz T
Medical Clinic, Department of Cardiology, University-Hospital Hamburg-Eppendorf, Hamburg, Germany.
Pacing Clin Electrophysiol. 2001 Feb;24(2):212-6. doi: 10.1046/j.1460-9592.2001.00212.x.
Automatic threshold tracking in cardiac pacemakers allows ventricular capture verification and self-adaptive pacing output regulation. The Autocapture algorithm detects the evoked response (ER) signal immediately after the pacing pulse to verify the efficacy of ventricular pacing. Before hospital delivery, the ER sensitivity must be programmed individually so that the pacemaker detects the ER signal adequately without sensing lead polarization. The aims of the study were to assess the frequency of patients in whom Autocapture could be activated and whether the ER sensitivity had to be adjusted after hospital discharge. The study included 44 patients who received the VVIR pacemaker Regency SR+ (St. Jude Medical) connected to the model 1450 T pacing lead. ER signal, lead polarization, and ER sensitivity were evaluated before hospital discharge and 1, 3, and 6 months after implantation. The system recommended activating Autocapture in 42 of 44 patients. The mean ER signal was 8.4+/-1.2 mV at discharge, 9.0+/-3.9 mV at month 1, 8.9+/-4.9 mV at month 3, and 9.3+/-4.5 mV at month 6. Polarization was 1.0+/-0.1 mV at discharge, 1.1+/-0.5 mV at month 1, 1.1+/-0.2 mV at month 3, and 1.1+/-0.5 mV at month 6. Mean ER sensitivity was 3.7+/-1.8 mV at discharge, 4.0+/-1.8 mV after 1, 4.1+/-2.2 mV after 3, and 4.1+/-1.8 mV after 6 months. ER sensitivity could remain unadjusted in 14 patients. Programming to a less sensitive ER setting from 2.9+/-1.2 mV to 4.3+/-1.5 mV was possible in 21 patients. Programming to a more sensitive ER setting from 4.1+/-1.1 mV to 2.5+/-0.9 mV was required in nine patients because of the decrease of the ER signal. The automatic threshold tracking algorithm Autocapture could be activated in 95% of patients. Programming to more sensitive ER settings was recommended in 21% of the patients after hospital discharge. Therefore, ER signal and polarization must be checked at each follow-up, as a decrease in ER signal amplitude can make reprogramming of the ER sensitivity necessary. There is no risk for the patient if the ER is not sensed, as high voltage backup stimulation is present.
心脏起搏器中的自动阈值跟踪可实现心室夺获验证和自适应起搏输出调节。自动夺获算法在起搏脉冲后立即检测诱发反应（ER）信号，以验证心室起搏的有效性。在出院前，必须单独设置ER灵敏度，以便起搏器能充分检测到ER信号而不感知导线极化。本研究的目的是评估可激活自动夺获功能的患者频率，以及出院后是否需要调整ER灵敏度。该研究纳入了44例接受VVIR起搏器Regency SR+（圣犹达医疗公司）并连接1450 T型号起搏导线的患者。在出院前以及植入后1、3和6个月评估ER信号、导线极化和ER灵敏度。该系统建议在44例患者中的42例激活自动夺获功能。出院时平均ER信号为8.4±1.2 mV，1个月时为9.0±3.9 mV，3个月时为8.9±4.9 mV，6个月时为9.3±4.5 mV。出院时极化值为1.0±0.1 mV，1个月时为1.1±0.5 mV，3个月时为1.1±0.2 mV，6个月时为1.1±0.5 mV。出院时平均ER灵敏度为3.7±1.8 mV，1个月后为4.0±1.8 mV，3个月后为4.1±2.2 mV，6个月后为4.1±1.8 mV。14例患者的ER灵敏度无需调整。21例患者可将ER设置从2.9±1.2 mV编程为较低灵敏度的4.3±1.5 mV。9例患者因ER信号降低，需要将ER设置从4.1±1.1 mV编程为较高灵敏度的2.5±0.9 mV。95%的患者可激活自动阈值跟踪算法自动夺获。出院后21%的患者建议将ER设置编程为更高的灵敏度。因此，每次随访时都必须检查ER信号和极化情况，因为ER信号幅度降低可能需要重新设置ER灵敏度。如果未感知到ER信号，对患者没有风险，因为存在高电压备用刺激。
