Why low-voltage shock impedance measurements fail to reliably detect insulation breaches in transvenous defibrillation leads.
Why low-voltage shock impedance measurements fail to reliably detect insulation breaches in transvenous defibrillation leads.
复制标题
为什么低压冲击阻抗测量无法可靠地检测经静脉除颤导线中的绝缘破损。
DOI：
10.1016/j.hrthm.2019.05.021
复制
发表时间：
2019
期刊：
影响因子：
5.5
通讯作者：
Kroll,MarkW
中科院分区：
文献类型：
--
作者：
Swerdlow,CharlesD;Porterfield,JohnE;Kottam,AnilG;Kroll,MarkW
背景植入式心律转复除颤器（ICD）使用电击阻抗（LVSZ）的低压测量来监测引线的完整性。目的确定LVSZ所需的导体之间的间隔距离，以检测在电击期间产生短路的绝缘破坏，方法我们模拟了ICD发生器（CAN）之间的囊袋绝缘破裂，和电缆连接到来自2个制造商的10根电极导线的远端线圈。将ICD和电极导线置于电解质浴中。聚苯乙烯片用于控制破裂-CAN分离。我们确定了800 V冲击期间短路的最大电极导线-CAN间隔以及固定间隔发生短路时的冲击强度。结果所有电极导线的最大击穿-CAN短路间隔为350-500 μm。短路时的最小冲击强度为650 - 771 V（24-32 J）。LVSZ从未触发警告，即使电缆的内部绝缘和CAN之间没有隔离。使用低电压脉冲，突破阻抗测量约500-1000 Ω。ConclusionLVSZ是不敏感的绝缘破坏，造成危及生命的，短路冲击。这种解释可能与LVSZ测量过程中的离子传导和等离子体放电中的自由电子传导之间的阻抗差异有关。
BackgroundImplantable cardioverter-defibrillators (ICDs) use low-voltage measures of shock impedance (LVSZ) to monitor integrity of leads.ObjectiveTo determine the separation distance between conductors required for LVSZ to detect insulation breaches that produce short circuits during shocks, causing failed defibrillation.MethodsWe simulated in-pocket insulation breaches between the ICD generator (CAN) and cables to the distal coil of 10 leads from 2 manufacturers. The ICD and lead were placed in an electrolyte bath. Polystyrene sheets were used to control the breach-CAN separation. We determined both the maximum lead-CAN separation for shorts during 800 V shocks and the shock strength at which shorts occurred for a fixed separation. We also calculated breach impedance and measured it using a low-voltage instrument.ResultsThe maximum breach-CAN separation for shorting was 350–500 μm for all leads. The minimum shock strength to short varied from 650 to 771 V (24–32 J). LVSZ never triggered a warning, even with no separation between the cable’s inner insulation and the CAN. Using low-voltage pulses, breach impedance was measured at approximately 500–1000 Ω.ConclusionLVSZ is insensitive to insulation breaches that cause life-threatening, shorted shocks. The explanation likely relates to impedance differences between ionic conduction during LVSZ measurements and free-electron conduction in plasma discharges.