Yamanouchi Yoshio, Mowrey Kent, Mazgalev Todor N, Wilkoff Bruce L, Tchou Patrick J
Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
Pacing Clin Electrophysiol. 2003 Dec;26(12):2213-8. doi: 10.1111/j.1540-8159.2003.00349.x.
The shape of the shock waveform influences defibrillation efficacy. However, the optimal combination between capacitance size and truncation/tilt which can determine monophasic waveform's shape, has not been determined for external defibrillation. The purpose of this study was to assess the effects of varying capacitance and tilt on external defibrillation using exponential monophasic waveforms. In a pig model of external defibrillation (n = 10, 30 +/- 6 kg), nine exponential monophasic waveforms combining three capacitance values (30 microF, 60 microF, and 120 microF) and three tilt values (55%, 75%, and 95%) were tested randomly. The energy and leading edge voltage at 50% defibrillation success (E50 and V50) were used to evaluate defibrillation efficacy. E50 and V50 were determined by the Bayesian technique. The lowest stored E50 for the 30microF, 60 microF, and 120 microF waveforms were 90 +/- 12 J (95% tilt), 106 +/- 45 J (55% tilt), and 107 +/- 52 J (75% tilt), respectively. The lowest V50 for the 30 microF, 60 microF, and 120 microF waveforms were 2,439 +/- 166 V (95% tilt), 1,849 +/- 375 V (55% tilt), and 1,301 +/- 322 V (75% tilt), respectively. The average current at external defibrillation threshold demonstrated a strength versus pulse duration relationship similar to that seen with pacing. Reducing capacitance has the same effect as truncating the waveform. The E50 is more sensitive to tilt values changes in larger capacitance waveforms. This study suggests that the optimal combination between capacitance and tilt may be 120 microF and 55%-75% for external defibrillation.
电击波形的形状会影响除颤效果。然而，对于体外除颤而言，能够决定单相波形形状的电容大小与截尾/倾斜度之间的最佳组合尚未确定。本研究的目的是评估使用指数单相波形时，不同电容和倾斜度对体外除颤的影响。在一个体外除颤猪模型（n = 10，体重30±6千克）中，随机测试了九种指数单相波形，这些波形组合了三个电容值（30微法、60微法和120微法）以及三个倾斜度值（55%、75%和95%）。使用50%除颤成功时的能量和前沿电压（E50和V50）来评估除颤效果。E50和V50通过贝叶斯技术确定。30微法、60微法和120微法波形的最低储存E50分别为90±12焦（95%倾斜度）、106±45焦（55%倾斜度）和107±52焦（75%倾斜度）。30微法、60微法和120微法波形 的最低V50分别为2439±166伏（95%倾斜度）、1849±375伏（55%倾斜度）和1301±322伏（75%倾斜度）。体外除颤阈值时的平均电流显示出强度与脉冲持续时间的关系，类似于起搏时观察到的关系。减小电容与截短波形具有相同的效果。E50对较大电容波形的倾斜度值变化更敏感。本研究表明，对于体外除颤，电容与倾斜度之间的最佳组合可能是120微法和55%-75%。
