Res J C, Reijsoo F J, van Woersem R J, Middelhoff C J, van Kalmthout P M, Zwart P, Westendorp P
Academic Medical Center, Amsterdam, The Netherlands.
Pacing Clin Electrophysiol. 1994 Nov;17(11 Pt 2):1883-8. doi: 10.1111/j.1540-8159.1994.tb03768.x.
The bottleneck of VDD systems is the reliable detection of the small atrial signals by a floating atrial electrode. Fractally iridium coated electrodes offer excellent sensing and pacing performance. In this study, the performance of such a floating atrial lead in P wave sensing and synchronous ventricular stimulation was examined. Atrial pacing was also used as a test of atrial wall contact.
A fractally iridium coated VDD lead was implanted in 18 patients. In 15 patients it was interfaced with a VDD pacemaker and in 3 patients with a DDD system depending on the P wave amplitude measured acutely (> or = 2 mV). Simultaneous recordings of the surface ECG and pacemaker telemetry were used to analyze P wave amplitudes and AV synchrony in different body positions, and during normal and deep breathing. Additionally, exercise tests based on daily life activities and 24-hour ECG monitoring were performed to test the pacemaker function.
During implantation P wave amplitudes were 1.86 mV +/- 1.08 mV (range 0.5-4.9 mV) and during follow-up (6.6 +/- 5.6 weeks) 0.18-3.8 mV. Holter recordings revealed reliable P wave sensing at a sensitivity setting of 0.5 mV (95.5%). P wave sensing was further improved by a higher atrial sensitivity. AV synchronous pacing > or = 99.9% was achieved in all patients. In 7 patients the atrial electrode could be positioned close to the atrial wall enabling atrial stimulation thresholds at an average of 4.3 volts.
This fractally iridium coated VVD lead allowed consistent and reliable P wave sensing at an atrial sensitivity as low as 0.5 mV in selected patients.
VDD系统的瓶颈在于通过漂浮心房电极可靠地检测小的心房信号。分形铱涂层电极具有出色的感知和起搏性能。在本研究中，对这种漂浮心房导线在P波感知和同步心室刺激方面的性能进行了检查。心房起搏也被用作心房壁接触的测试。
将一根分形铱涂层的VDD导线植入18例患者体内。根据急性测量的P波幅度（≥2mV），15例患者将其与VDD起搏器连接，3例患者与DDD系统连接。同时记录体表心电图和起搏器遥测数据，以分析不同体位、正常呼吸和深呼吸时的P波幅度及房室同步性。此外，还进行了基于日常生活活动的运动试验和24小时心电图监测，以测试起搏器功能。
植入期间P波幅度为1.86mV±1.08mV（范围0.5 - 4.9mV），随访期间（6.6±5.6周）为0.18 - 3.8mV。动态心电图记录显示，在灵敏度设置为0.5mV时，P波感知可靠（95.5%）。更高的心房灵敏度进一步改善了P波感知。所有患者均实现了≥99.9%的房室同步起搏。7例患者的心房电极能够靠近心房壁定位，平均心房刺激阈值为4.3伏。
这种分形铱涂层的VVD导线在选定患者中，能在低至0.5mV的心房灵敏度下实现一致且可靠的P波感知。
