Rusconi L, Sigliano R, Mininno A
Sezione di Cardiologia, Ospedale G. Ceccarini, Riccione, Italy.
Pacing Clin Electrophysiol. 1998 Oct;21(10):1943-8. doi: 10.1111/j.1540-8159.1998.tb00014.x.
SPEM is a multicenter randomized double-blind study performed to test the acute and chronic electrophysiological behavior of three different ventricular leads: (1) an ion exchange membrane with 30-microgram dexamethasone elution in a contoured activated carbon tip lead (Membrane 1400T, 30 patients); (2) the same lead design without steroid (Membrane 1401T, 24 patients); and (3) the same lead design without steroid or membrane (control group, 27 patients). Twenty-three of the 81 patients were women; the mean age for all patients was 74 +/- 10 years. Parameters are calculated both in uni- and bipolar configuration at implant and at follow-up after 1, 5, 15, 30, 90, 180, and 360 days. Implant threshold (chronaxie = 0.413 +/- 0.280 ms, rheobase = 0.264 +/- 0.099 V), signal amplitude (13.45 +/- 5.87 mV), and slew rate (2.05 +/- 1.38 V/s) reveal no significant differences. Pacing impedance values both at implant (unipolar 571 +/- 165 omega; bipolar 605 +/- 123 omega) and at follow-ups (unipolar 480 +/- 72 omega; bipolar 518 +/- 75 omega) are slightly lower in the unipolar configuration. At 15 and 30-day follow-ups, control group and nonsteroid leads show a higher threshold value growth (in unipolar from 0.16 +/- 0.11 to 1.19 +/- 0.85 microJ; in bipolar from 0.18 +/- 0.13 to 1.24 +/- 0.88 microJ) than the membrane steroid leads (in unipolar from 0.13 +/- 0.11 to 0.70 +/- 0.39 microJ; in bipolar from 0.23 +/- 0.32 to 0.76 +/- 0.36 microJ); the threshold of nonsteroid leads decreases after 1-3 months and it settles at the same threshold level of the leads with membrane and steroid (in unipolar 0.60 +/- 0.33 microJ; in bipolar 0.55 +/- 0.26 microJ), which has been stable since the first month. The ion exchange membrane is effective in reducing the chronic pacing threshold like acute steroid elution at low doses, but membrane alone does not prevent an acute pacing threshold increase through the first month postimplant.
SPEM是一项多中心随机双盲研究，旨在测试三种不同心室导线的急性和慢性电生理行为：（1）一种在轮廓活性炭尖端导线中洗脱30微克地塞米松的离子交换膜（膜1400T，30例患者）；（2）相同的导线设计但无类固醇（膜1401T，24例患者）；（3）相同的导线设计但无类固醇或膜（对照组，27例患者）。81例患者中有23例为女性；所有患者的平均年龄为74±10岁。在植入时以及植入后1、5、15、30、90、180和360天的随访中，以单极和双极配置计算参数。植入阈值（时值=0.413±0.280毫秒，基强度=0.264±0.099伏）、信号幅度（13.45±5.87毫伏）和 slew速率（2.05±1.38伏/秒）均无显著差异。单极配置下植入时（单极571±165欧姆；双极605±123欧姆）和随访时（单极480±72欧姆；双极518±75欧姆）的起搏阻抗值略低。在15天和30天的随访中，对照组和无类固醇导线的阈值增长较高（单极从0.16±0.11微焦增加到1.19±0.85微焦；双极从0.18±0.13微焦增加到1.24±0.88微焦），高于膜类固醇导线（单极从0.13±0.11微焦增加到0.70±0.39微焦；双极从0.23±0.32微焦增加到0.76±0.36微焦）；无类固醇导线的阈值在1至3个月后降低，并稳定在与有膜和类固醇导线相同的阈值水平（单极0.60±0.33微焦；双极0.55±0.26微焦），自第一个月起就一直稳定。离子交换膜在降低慢性起搏阈值方面与低剂量急性类固醇洗脱一样有效，但单独的膜并不能防止植入后第一个月内急性起搏阈值的增加。
