Cohen N M, Damiano R J, Wechsler A S
Department of Surgery, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0645, USA.
Ann Thorac Surg. 1995 Sep;60(3):858-63. doi: 10.1016/0003-4975(95)00210-C.
Mounting clinical and experimental evidence suggests that postoperative myocardial dysfunction is a frequent consequence of surgical global ischemia and reperfusion, despite our modern techniques of myocardial protection. The ubiquitous use of hyperkalemic depolarizing solutions in all forms of cardioplegia may be partly responsible for this phenomenon because of the known ongoing metabolic processes and damaging transmembrane ionic fluxes that occur at depolarized membrane potentials. Cardiac arrest at hyperpolarized potentials, the natural resting state of the heart, may avoid the shortcomings of depolarized arrest and provide an alternative means of myocardial protection.
An adenosine triphosphate-sensitive potassium channel opener, aprikalim, was used to induce hyperpolarized arrest. Aprikalim was able to produce sustained and reproducible electromechanical arrest that was reversible by reperfusion.
In isolated heart models, when compared with depolarized hyperkalemic arrest, hyperpolarized arrest afforded better protection from global normothermic ischemia and resulted in better postischemic recovery of function upon reperfusion. Preliminary studies in a porcine cardiopulmonary bypass model also have revealed that hyperpolarized arrest can be achieved in a model more closely approximating the clinical setting, and can effectively protect the heart during normothermic surgical global ischemia.
Hyperpolarized cardiac arrest may offer an effective alternative to traditional potassium arrest.
越来越多的临床和实验证据表明，尽管我们有现代心肌保护技术，但术后心肌功能障碍仍是手术性全心缺血和再灌注常见的后果。在各种形式的心脏停搏中普遍使用高钾去极化溶液可能是造成这种现象的部分原因，因为已知在去极化膜电位时会发生持续的代谢过程和有害的跨膜离子通量。心脏在超极化电位（心脏的自然静息状态）下停搏可能会避免去极化停搏的缺点，并提供一种心肌保护的替代方法。
使用一种三磷酸腺苷敏感性钾通道开放剂阿普卡林来诱导超极化停搏。阿普卡林能够产生持续且可重复的电机械停搏，再灌注可使其逆转。
在离体心脏模型中，与去极化高钾停搏相比，超极化停搏能更好地保护心脏免受全心常温缺血的影响，并在再灌注后实现更好的缺血后功能恢复。在猪体外循环模型中的初步研究也表明，在更接近临床情况的模型中可以实现超极化停搏，并且在常温手术性全心缺血期间能有效保护心脏。
超极化心脏停搏可能为传统钾停搏提供一种有效的替代方法。
