Poole J E, Bardy G H, Kudenchuk P J, Dolack G L, Raitt M H, Mehra R, Johnson G
Department of Medicine, University of Washington, Seattle, USA.
Pacing Clin Electrophysiol. 1995 Jul;18(7):1369-73. doi: 10.1111/j.1540-8159.1995.tb02598.x.
A unipolar defibrillation system using a single right ventricular (RV) electrode and the active shell or container of an implantable cardioverter defibrillator situated in a left infraclavicular pocket has been shown to be as efficient in defibrillation as an epicardial lead system. Additional improvements in this system would have favorable practice implications and could derive from alterations in pulse waveform shape. The specific purpose of this study is to determine whether defibrillation efficacy can be improved further in humans by lowering biphasic waveform tilt.
We prospectively and randomly compared the defibrillation efficacy of a 50% and a 65% tilt asymmetric biphasic waveform using the unipolar defibrillation system in 15 consecutive cardiac arrest survivors prior to implantation of a presently available standard transvenous defibrillation system. The RV defibrillation electrode has a 5-cm coil located on a 10.5 French lead and was used as the anode. The system cathode was the active 108 cm2 surface area shell (or "CAN") of a prototype titanium alloy pulse generator placed in the left infraclavicular pocket. The defibrillation pulse derived from a 120-microF capacitor and was delivered from RV-->CAN, with RV positive with respect to the CAN during the initial portion of the cycle. Defibrillation threshold (DFT) stored energy, delivered energy, leading edge voltage and current, pulse resistance, and pulse width were measured for both tilts examined.
The unipolar single lead system, RV-->CAN, using a 65% tilt biphasic pulse resulted in a stored energy DFT of 8.7 +/- 5.7 J and a delivered energy DFT of 7.6 +/- 5.0 J. In all 15 patients, stored and delivered energy DFTs were < 20 J. The 50% tilt biphasic pulse resulted in a stored energy DFT of 8.2 +/- 5.4 J and a delivered energy DFT of 6.1 +/- 4.0 J; P = 0.69 and 0.17, respectively. As with the 65% tilt pulse, all 15 patients had stored and delivered energy DFTs < 20 J.
The unipolar single lead transvenous defibrillation system provides defibrillation at energy levels comparable to that reported with epicardial lead systems. This system is not improved by use of a 50% tilt biphasic waveform instead of a standard 65% tilt biphasic pulse.
一种单极除颤系统，使用单个右心室（RV）电极以及位于左锁骨下口袋的植入式心脏复律除颤器的有源外壳或容器，已被证明在除颤方面与心外膜导联系统一样有效。该系统的进一步改进将具有良好的实际意义，并且可以通过改变脉冲波形形状来实现。本研究的具体目的是确定在人类中降低双相波形倾斜度是否可以进一步提高除颤效果。
在植入当前可用的标准经静脉除颤系统之前，我们前瞻性地、随机地比较了使用单极除颤系统的50%倾斜度和65%倾斜度非对称双相波形对15例连续心脏骤停幸存者的除颤效果。右心室除颤电极在10.5F的导线上有一个5厘米的线圈，并用作阳极。系统阴极是放置在左锁骨下口袋的原型钛合金脉冲发生器的108平方厘米有源表面积外壳（或“CAN”）。除颤脉冲由一个120微法的电容器产生，并从右心室→CAN传递，在周期的初始部分右心室相对于CAN为正。测量了两种倾斜度下的除颤阈值（DFT）、存储能量、传递能量、前沿电压和电流、脉冲电阻以及脉冲宽度。
使用65%倾斜度双相脉冲的单极单导联系统右心室→CAN，其存储能量DFT为8.7±5.7J，传递能量DFT为7.6±5.0J。在所有15例患者中，存储和传递能量DFT均<20J。50%倾斜度双相脉冲的存储能量DFT为8.2±5.4J，传递能量DFT为6.1±4.0J；P分别为0.69和0.17。与65%倾斜度脉冲一样，所有15例患者的存储和传递能量DFT均<20J。
单极单导联经静脉除颤系统在能量水平上提供的除颤效果与心外膜导联系统报道的相当。使用50%倾斜度双相波形而非标准的65%倾斜度双相脉冲并不能改善该系统。
