Gliner B E, Lyster T E, Dillion S M, Bardy G H
Department of Medicine, University of Washington, Seattle, USA.
Circulation. 1995 Sep 15;92(6):1634-43. doi: 10.1161/01.cir.92.6.1634.
Biphasic waveforms have had a favorable impact on internal defibrillation but have seen minimal use in transthoracic defibrillation systems. The purpose of this study was to compare monophasic and biphasic waveforms for transthoracic defibrillation in swine.
Three interrelated studies were performed in 19 swine to establish the relative transthoracic defibrillation efficacy of biphasic shock waveforms. In study 1, we measured voltage (V50) and energy (E50) strength-duration curves for monophasic and biphasic truncated exponential waveforms. We then independently examined the effects of phase duration and tilt on biphasic waveform defibrillation with a total waveform duration from study 1 that provided the minimum V50 (study 2) and the minimum E50 (study 3). At each pulse duration tested in study 1, biphasic waveforms defibrillated with significantly less voltage and energy than monophasic waveforms. At a duration of 12 ms, there was a voltage minimum for biphasic waveform defibrillation. At this duration, V50 was 1378 +/- 505 V for the biphasic waveform compared with 2185 +/- 361 V for the monophasic waveform, P = .01. For both monophasic and biphasic waveforms, E50 increased with pulse duration. With a total pulse duration of 12 ms, E50 was 169 +/- 101 J for the biphasic waveform compared with 414 +/- 114 J for the monophasic waveform, P = .003. In study 2, optimization of phase duration and total tilt reduced the defibrillation requirements of the 12-ms "minimum voltage" biphasic waveform to 1284 +/- 187 V and 129 +/- 36 J. In study 3, the 8-ms "minimum energy" biphasic waveform had an E50 of 115 +/- 35 J that was 11% less than the 12-ms biphasic waveform, P = .11; however, voltage requirements of 1476 +/- 239 V were 15% higher, P = .005.
This study demonstrates the superiority of truncated biphasic waveforms over truncated monophasic waveforms for transthoracic defibrillation of swine. Biphasic waveforms should prove as advantageous at reducing voltage and energy requirements for transthoracic defibrillation as they have for internal defibrillation.
双相波对体内除颤产生了有利影响，但在经胸除颤系统中的应用却很少。本研究的目的是比较单相波和双相波在猪经胸除颤中的效果。
在19头猪身上进行了三项相互关联的研究，以确定双相电击波经胸除颤的相对效果。在研究1中，我们测量了单相波和双相截断指数波的电压（V50）和能量（E50）强度-持续时间曲线。然后，我们分别研究了相位持续时间和倾斜度对双相波除颤的影响，双相波的总波形持续时间取自研究1中能提供最小V50的波形（研究2）和最小E50的波形（研究3）。在研究1中测试的每个脉冲持续时间下，双相波除颤所需的电压和能量均明显低于单相波。在12毫秒的持续时间时，双相波除颤存在电压最小值。在此持续时间下，双相波的V50为1378±505伏，而单相波为2185±361伏，P = 0.01。对于单相波和双相波，E50均随脉冲持续时间增加。在总脉冲持续时间为12毫秒时，双相波的E50为169±101焦，而单相波为414±114焦，P = 0.003。在研究2中，优化相位持续时间和总倾斜度后，12毫秒“最小电压”双相波的除颤要求降至1284±187伏和129±36焦。在研究3中，8毫秒“最小能量”双相波的E50为115±35焦，比12毫秒双相波低11%，P = 0.11；然而，其电压要求为1476±239伏，高出15%，P = 0.005。
本研究证明了截断双相波在猪经胸除颤方面优于截断单相波。双相波在降低经胸除颤的电压和能量要求方面应与在体内除颤中一样具有优势。
