Danilovic D, Breivik K, Hoff P I, Ohm O J
Medical Department A, Haukeland University Hospital, Bergen, Norway.
Pacing Clin Electrophysiol. 1997 Nov;20(11):2799-809. doi: 10.1111/j.1540-8159.1997.tb05438.x.
To raise pacing impedance and reduce battery current drain, new tined steroid-eluting leads were developed with 1.2-mm2 hemispherical electrodes, instead of conventional 5-8 mm2. Twenty-two unipolar J-shaped atrial leads and 25 unipolar ventricular leads (models 4533 and 4033, respectively) were implanted in 33 consecutive patients and followed for a mean of 25 months (range 18-29). Handling characteristics of atrial leads were found favorable. The leads slipped easily into the right atrial appendage and were easy to position. Handling characteristics of ventricular leads were satisfying, but more efforts had to be applied to cross the tricuspid valve. Special care was taken to avoid perforation of the myocardium due to the small lead tip. Following implantation, four ventricular and one atrial lead exhibited instability of pacing thresholds that resolved spontaneously within 1-3 days of implantation. Except for this, no lead malfunctioned. The reoperation rate was zero. The mean electrogram amplitudes of 15 mV (ventricle) and 4 mV (atrium), and the mean chronic pacing threshold of 0.085 ms at 1.6 V (app. 0.43 V at 0.5 ms) were comparable with the best values seen in the literature on passive fixation leads. The rest of the electrophysiological parameters were enhanced: mean pacing impedances were 984 omega (acute) and 900 Q (chronic), mean slew rates 3.26 V/s (ventricle) and 1.75 V/s (atrium), mean acute voltage threshold at 0.5 ms was 0.25 V, mean current and energy thresholds calculated at 0.5 ms were 260 microA and 32 nJ (acute) and 478 microA and 103 nJ (chronic). The electrical characteristics of these leads provide for increased pacemaker longevity in combination with substantial safety margins for pacing and sensing.
为提高起搏阻抗并减少电池电流消耗，研发了新型带激素洗脱的有翼电极导线，其采用1.2平方毫米的半球形电极，而非传统的5 - 8平方毫米电极。将22根单极J形心房导线和25根单极心室导线（分别为4533型和4033型）植入33例连续患者体内，并平均随访25个月（范围18 - 29个月）。发现心房导线的操作特性良好。导线很容易滑入右心耳且易于定位。心室导线的操作特性令人满意，但穿过三尖瓣时需要更多努力。由于导线尖端较小，需特别小心避免心肌穿孔。植入后，4根心室导线和1根心房导线出现起搏阈值不稳定，在植入后1 - 3天内自发恢复。除此之外，没有导线发生故障。再次手术率为零。15 mV（心室）和4 mV（心房）的平均电图幅度，以及1.6 V时0.085 ms的平均慢性起搏阈值（0.5 ms时约为0.43 V）与文献中关于被动固定导线的最佳值相当。其余电生理参数有所改善：平均起搏阻抗急性时为984欧姆，慢性时为900欧姆；平均 slew 率心室为3.26 V/s，心房为1.75 V/s；0.5 ms时的平均急性电压阈值为0.25 V；0.5 ms时计算的平均电流和能量阈值急性时为260微安和32纳焦，慢性时为478微安和103纳焦。这些导线的电气特性可延长起搏器寿命，并为起搏和感知提供足够的安全裕度。
