Leitch J W, Yee R, Klein G J, Jones D L
Department of Medicine, University of Western Ontario, Canada.
Pacing Clin Electrophysiol. 1990 Apr;13(4):410-6. doi: 10.1111/j.1540-8159.1990.tb02055.x.
We assessed the value and safety of using a low voltage test shock to predict cardiac and electrode impedance during subsequent high voltage, transvenous, sequential pulse shocks. Two transvenous defibrillation catheters were inserted in 15 patients undergoing electrophysiology study for the evaluation of ventricular tachycardia/fibrillation. A sequential pulse test shock at stored voltage of 50 or 100 volts was delivered during sinus rhythm and high voltage therapeutic shocks were delivered during induced ventricular tachycardia/fibrillation. The test shocks were well tolerated and caused only minimal discomfort. Peak delivered voltage for each pulse of the test shock ranged from 34 to 116 volts (mean 62 +/- 27) and for each pulse of the therapeutic shocks from 186 to 778 volts (mean 435 +/- 146). There was a very strong relationship between the impedance of the test and the mean impedance of the therapeutic shocks (R = 0.89, P less than 0.001). The mean impedance of the test shock was slightly greater than the mean impedance of the test shock as slightly greater than the mean impedance of the therapeutic shocks (mean 90 +/- 24 ohms compared to 77 +/- 16 ohms, P less than 0.001), with a maximum difference between test and therapeutic shock impedances of 39 ohms (mean difference 8.4 +/- 10.3 ohms). There was a significant inverse relationship between impedance and peak current (R = -0.49, P = 0.001). Cardiac and electrode impedance during transvenous defibrillation can be predicted reliably and safely by a low voltage test shock. This technique provides a safe and simple method to ensure appropriate connections and electrode function for subsequent countershock therapies.
我们评估了在随后的高电压、经静脉、顺序脉冲电击期间，使用低电压测试电击来预测心脏和电极阻抗的价值及安全性。在15例接受电生理研究以评估室性心动过速/心室颤动的患者中插入两根经静脉除颤导管。在窦性心律期间给予存储电压为50或100伏的顺序脉冲测试电击，在诱发的室性心动过速/心室颤动期间给予高电压治疗电击。测试电击耐受性良好，仅引起轻微不适。测试电击每个脉冲的峰值输出电压范围为34至116伏（平均62±27），治疗电击每个脉冲的峰值输出电压范围为186至778伏（平均435±146）。测试电击的阻抗与治疗电击的平均阻抗之间存在非常强的相关性（R = 0.89，P＜0.001）。测试电击的平均阻抗略大于治疗电击的平均阻抗（分别为平均90±24欧姆和77±16欧姆，P＜0.001），测试电击与治疗电击阻抗的最大差值为39欧姆（平均差值8.4±10.3欧姆）。阻抗与峰值电流之间存在显著的负相关（R = -0.49，P = 0.001）。经静脉除颤期间的心脏和电极阻抗可以通过低电压测试电击可靠且安全地预测。该技术提供了一种安全且简单的方法，以确保后续电击治疗的适当连接和电极功能。
