Chapman P D, Wetherbee J N, Vetter J W, Troup P, Souza J
Medical College of Wisconsin, Division of Cardiology, Milwaukee 53226.
Pacing Clin Electrophysiol. 1988 Jul;11(7):1045-50. doi: 10.1111/j.1540-8159.1988.tb03950.x.
Six anesthetized dogs (wgt 19.6 + 1.1 kg) underwent defibrillation trials using truncated monophasic pulses of 2.5-20 msec in duration. The current pathway consisted of a 4 cm2 RV catheter electrode (cathode) and a 13.9 cm2 subcutaneous chest wall patch (anode). Fibrillation was induced by alternating current and defibrillation attempted 10 seconds later. Only one test shock was assessed for each fibrillation episode. The various durations were tested randomly, and the minimum peak voltage and energy resulting in defibrillation was determined for each. Shorter pulse durations were associated with lower energies with pulses of 2.5-15 msec having significantly lower energy thresholds than shocks of 20 msec (P less than 0.05). The relationship between duration and voltage threshold is hyperbolic with minimum voltage between 7.5 and 12.5 msec while the shortest and longest pulses were associated with the highest voltage thresholds. Shocks of 5 to 15 msec were associated with significantly lower voltage threshold than 2.5 msec pulses (P less than 0.05). The threshold average current (Iav) reached a nadir at 10 msec. Shocks in the midrange of those tested resulted in the best combination of low average current and energy requirements for defibrillation using this nonthoracotomy lead system.
六只麻醉犬（体重19.6±1.1千克）使用持续时间为2.5 - 20毫秒的截断单相脉冲进行除颤试验。电流通路由一个4平方厘米的右心室导管电极（阴极）和一个13.9平方厘米的胸壁皮下贴片（阳极）组成。通过交流电诱发心室颤动，并在10秒后尝试除颤。每次心室颤动发作仅评估一次测试电击。随机测试各种持续时间，并确定每次除颤所需的最小峰值电压和能量。较短的脉冲持续时间与较低的能量相关，2.5 - 15毫秒的脉冲具有明显低于20毫秒电击的能量阈值（P小于0.05）。持续时间与电压阈值之间的关系呈双曲线，在7.5至12.5毫秒之间电压最低，而最短和最长的脉冲与最高电压阈值相关。5至15毫秒的电击与2.5毫秒脉冲相比，电压阈值显著降低（P小于0.05）。阈值平均电流（Iav）在10毫秒时达到最低点。使用这种非开胸导联系统进行除颤时，测试范围内的中等时长电击能实现低平均电流和能量需求的最佳组合。
