Walcott Gregory P, Killingsworth Cheryl R, Ideker Raymond E
Cardiac Rhythm Management Laboratory, Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Volker Hall B140, 1670 University Blvd., Birmingham, AL 35294, USA.
Resuscitation. 2003 Oct;59(1):59-70. doi: 10.1016/s0300-9572(03)00161-8.
Sufficiently strong defibrillation shocks will cause temporary or permanent damage to the heart. Weak defibrillation shocks do not cause any damage to the heart but also do not defibrillate. A relevant and practical question is what range of shock energies is most likely to defibrillate while not causing damage to the heart. This question is most difficult to answer in the pre-hospital defibrillation setting where the patients' size and shape vary, placement of the defibrillation patches vary, and the etiology of their arrhythmia varies. Unlike internal defibrillators, which are tested at implantation, efficacy of an external defibrillator is determined only once, when it is most needed. This review discusses shock damage and dysfunction caused by monophasic waveforms as well as biphasic waveforms. Evidence is presented suggesting that for perfused hearts, the threshold for damage is well above any shock size delivered clinically. For non-perfused hearts, both in humans and animals, evidence is presented that monophasic shocks of up to 5 J/kg do not cause any more cardiac damage/dysfunction than that associated with smaller shocks and that much of this damage is caused by the ischemic period itself rather than the shock. Although many patients can be defibrillated with 150 J (2.2 J/kg) biphasic shocks, some patients may require biphasic shocks up to 360 J (5 J/kg) to be defibrillated. Studies still need to be performed comparing the efficacy and damaging effects of 360 J biphasic shocks to 150 J biphasic shocks. Until those studies are completed, it seems reasonable to use the same 360 J (5 J/kg) energy limit for biphasic shocks as for monophasic shocks.
足够强的除颤电击会对心脏造成暂时或永久性损伤。较弱的除颤电击不会对心脏造成任何损伤，但也无法实现除颤。一个相关且实际的问题是，何种电击能量范围最有可能实现除颤，同时又不会对心脏造成损伤。在院前除颤环境中，这个问题最难回答，因为患者的体型和形状各异，除颤贴片的放置位置不同，心律失常的病因也不同。与植入时进行测试的体内除颤器不同，体外除颤器的疗效仅在最需要时才确定一次。本综述讨论了单相波形和双相波形引起的电击损伤和功能障碍。有证据表明，对于灌注心脏，损伤阈值远高于临床上传递的任何电击强度。对于人类和动物的非灌注心脏，有证据表明，高达5 J/kg的单相电击造成的心脏损伤/功能障碍并不比小电击更多，而且这种损伤大多是由缺血期本身而非电击造成的。尽管许多患者可以用150 J（2.2 J/kg）的双相电击实现除颤，但有些患者可能需要高达360 J（5 J/kg）的双相电击才能除颤。仍需进行研究，比较360 J双相电击与150 J双相电击的疗效和损伤效果。在这些研究完成之前，对双相电击使用与单相电击相同的360 J（5 J/kg）能量限制似乎是合理的。
