Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhong Shan Hospital of Fudan University, Shanghai, China.
PLoS One. 2013;8(3):e57727. doi: 10.1371/journal.pone.0057727. Epub 2013 Mar 5.
Magnitude of current of injury (COI) consequent to pacemaker lead fixation is recognized as a predictor of acute lead stability. It is unclear whether dynamic monitoring of COI after lead fixation provides additional information beyond a single assessment performed at the time of fixation.
This study was aimed to test the hypothesis that the time course of COI is related to acute lead stability.
Active fixation leads with fixed screw were anchored to either Langendorff-perfused rabbit hearts endocardially or in vivo hearts epicardially in manners of contact the helix with no rotation, half rotation and full rotation, respectively. Intracardiac electrogram (EGM) was monitored dynamically from onset to resolution of COI, and magnitudes of intrinsic R wave and COI, including ST-segment elevation, ST/R and intracardiac EGM duration (IED), were measured. A digital force gauge was applied to assess lead stability. In vitro, COI in contacted leads was significantly smaller than those in half rotated (p<0.05) and fully rotated leads (p<0.05), and presented most precipitous recovery to baseline (1.5±1.1 min, p<0.05). Half-rotated and fully rotated leads manifested the same magnitude of COI right after placement. However, the time course of COI was significantly longer in fully rotated leads than that in half rotated leads (26.5±2.8 min vs. 5.6±2.0 min, p<0.05). Similar findings were observed in vivo. The time course of COI was significantly correlated with the force needed to detach the lead from myocardium (r = 0. 72, n = 48, p<0.001).
Time course of COI is related to acute lead stability in rabbits. One might be misled by a single assessment of COI magnitude right after lead placement, whereas persistence of COI is likely to be a useful indicator of adequate lead stability.
起搏器导线固定后损伤电流（COI）的幅度被认为是急性导线稳定性的预测指标。目前尚不清楚在导线固定时进行单次评估后，动态监测 COI 是否会提供额外信息。
本研究旨在检验 COI 时间过程与急性导线稳定性相关的假设。
主动固定导线的固定螺丝分别以无旋转、半旋转和全旋转的方式与螺旋接触固定在Langendorff 灌注兔心的心内膜或体内心脏的心外膜上。从 COI 的起始到消退，动态监测心内电图（EGM），测量固有 R 波和 COI 的幅度，包括 ST 段抬高、ST/R 和心内 EGM 持续时间（IED）。使用数字测力计评估导线稳定性。在体外，接触导线的 COI 明显小于半旋转（p<0.05）和完全旋转（p<0.05）导线，且恢复至基线的速度最快（1.5±1.1 min，p<0.05）。半旋转和完全旋转的导线在放置后即刻具有相同幅度的 COI。然而，完全旋转的导线的 COI 时间过程明显长于半旋转的导线（26.5±2.8 min 比 5.6±2.0 min，p<0.05）。在体内也观察到了类似的发现。COI 的时间过程与从心肌上分离导线所需的力显著相关（r = 0.72，n = 48，p<0.001）。
在兔中，COI 的时间过程与急性导线稳定性相关。在导线放置后立即进行 COI 幅度的单次评估可能会产生误导，而 COI 的持续存在可能是导线稳定性的有用指标。
