Walcott G P, Rollins D L, Smith W M, Ideker R E
Department of Medicine, Duke University Medical Center, North Carolina, USA.
Pacing Clin Electrophysiol. 1996 Jun;19(6):945-54. doi: 10.1111/j.1540-8159.1996.tb03391.x.
In this study, we examined the effect of changing capacitor values between phases of a biphasic waveform with the goal of lowering leading edge voltage (LEV), total delivered energy (TDE), and total stored energy (TSE).
Defibrillation thresholds were determined in 18 open-chest swine using epicardial patch electrodes. In part I, three combinations of capacitors were tested: 150:150 microF; 150:300 microF; and 300:150 microF. Waveform durations were 6/0, 6/2, 6/4, 6/6, and 6/8 ms. In part II, phase 1 capacitance was 150 microF. Three phase 2 capacitance values were used: 150 microF; 75 microF; and 37.5 microF. Phase 2 LEV was a multiple of phase 1 trailing edge voltage: x 0.5; x 0.75; x 1; x 2; x 3; and x 4. A 3.5/2.0 ms biphasic waveform was used. In part III, thresholds were determined for two sets of capacitor values, which can be created by switching a pair of capacitors from in parallel to in series, 150:37.5 microF and 300:75 microF, and nine waveform durations, 4/0, 4/2, 4/4, 6/0, 6/3, 6/6, 8/0, 8/4 and 8/8 ms.
In part I, the 300:150 microF system defibrillated with the lowest LEV, TDE and TSE were not different for any of the biphasic waveforms tested except for the 6/8 ms, which was higher. In part II, there was no difference in LEV among any of the three phase 2 capacitor values. LEV was lowest for the x 2, x 3, x 4 multipliers. Peak voltage was lowest for the x 1 and x 2 multipliers. TDE was lowest for the x 0.5, x 0.75, x 1, and x 2 multipliers. In part III, the 300:75 microF system defibrillated at a lower LEV than did the 150:37.5 microF system. The 150:37.5 microF system defibrillated at a lower total delivered energy than did the 300:75 microF.
These results suggest that defibrillation can be accomplished with lower LEV, TDE, and TSE if two capacitors are switched from a parallel configuration to a series configuration between phases of the biphasic waveform.
在本研究中，我们研究了改变双相波形各阶段电容值对降低前沿电压（LEV）、总输送能量（TDE）和总存储能量（TSE）的影响。
使用心外膜贴片电极在18只开胸猪身上测定除颤阈值。在第一部分，测试了三种电容组合：150:150微法；150:300微法；以及300:150微法。波形持续时间为6/0、6/2、6/4、6/6和6/8毫秒。在第二部分，第一阶段电容为150微法。使用了三个第二阶段电容值：150微法；75微法；以及37.5微法。第二阶段的LEV是第一阶段后沿电压的倍数：x 0.5；x 0.75；x 1；x 2；x 3；以及x 4。使用了3.5/2.0毫秒的双相波形。在第三部分，测定了两组电容值的阈值，这两组电容值可通过将一对电容器从并联切换为串联来创建，即150:37.5微法和300:75微法，以及九个波形持续时间，4/0、4/2、4/4、6/0、6/3、6/6、8/0、8/4和8/8毫秒。
在第一部分，300:150微法系统除颤时LEV最低，除6/8毫秒（该值较高）外，所测试的任何双相波形的TDE和TSE均无差异。在第二部分，三个第二阶段电容值中的任何一个的LEV均无差异。对于x 2、x 3、x 4倍数，LEV最低。对于x 1和x 2倍数，峰值电压最低。对于x 0.5、x 0.75、x 1和x 2倍数，TDE最低。在第三部分，300:75微法系统除颤时的LEV低于150:37.5微法系统。150:37.5微法系统除颤时的总输送能量低于300:75微法系统。
这些结果表明，如果在双相波形的各阶段之间将两个电容器从并联配置切换为串联配置，则可以用更低的LEV、TDE和TSE实现除颤。
