Cohen H C, Arbel E R
Med Clin North Am. 1976 Mar;60(2):343-67. doi: 10.1016/s0025-7125(16)31914-9.
Techniques of electrical pacing for the treatment of tachycardias are multiple. The choice of a suitable method for a particular tachycardia depends upon understanding the mechanism of the tachycardia and the pacing characteristics that will lead to interruption or suppression of the tachycardia, or to ventricular slowing. Electrical pacing is indicated for tachycardias when drug therapy alone has failed or cannot be initiated or continued, and only for those tachycardias that are likely to respond to this type of electrical stimulation. In either the circus movement type or the ectopic pacemaker type an ectopic tachycardia is more likely to be suppressed if the pacing site is near the site of origin of the tachycardia. Pacing more rapidly than the basic rate in order to prevent or abolish tachycardias is termed overdrive suppression. The mechanisms responsible for this phenomenon may be associated with release of acetylcholine, release of potassium, activation of an electrogenic sodium pump, increase in cardiac output and coronary flow, decrease in size of the heart with a consequent decrease in wall tension, and decrease in the inhomogeneity of recovery of excitability that occurs at more rapid rates in the non-ischemic heart. All of these effects of pacing suppress accelerated pacemaker activity or prevent emergence of conditions favorable for development of circus movement tachycardias. Paired, coupled, or rapid atrial pacing may improve ventricular performance or slow ventricular rate, or both, without abolishing the ectopic pacemaker activity. Atrial pacing with pacing sites located at endocardial, epicardial, coronary sinus, trans-septal, or esophageal locations may interrupt or prevent rapid supraventricular or ventricular arrhythmias. Similarly, ventricular pacing at endocardial, epicardial, myocardial, or transthoracic sites may be equally effective. Artificial pacing has abolished almost every type of tachycardia. Ventricular fibrillation always, and atrial fibrillation usually, require countershock if electrical treatment is to be employed, although defibrillation of the atria by rapid pacing has been reported once. Unipolar or bipolar pacemakers may be used temporarily, or permanently after implantation. Pacing rates used to abolish supraventricular tachycardias range from single premature beats to alternating current atrial pacing at 3600 cycles per minute. Artificial electrical stimulation of the heart may be on demand, or may be competitive (fixed rate). External magnets, induction coil coupling, and radio frequency signals allow competitive pacing to be used intermittently, with permanently implanted pacemakers. Thus, electrical pacing of the heart is a technique of major importance for the control of rapid heart rates.
用于治疗心动过速的电起搏技术多种多样。针对特定心动过速选择合适的方法取决于对心动过速机制以及能导致心动过速中断、抑制或心室率减慢的起搏特性的理解。当单独药物治疗失败或无法启动或持续时，电起搏适用于心动过速，且仅适用于可能对这种电刺激有反应的心动过速。在折返运动型或异位起搏点型中，如果起搏部位靠近心动过速的起源部位，异位性心动过速更有可能被抑制。为预防或消除心动过速而以高于基础心率的频率起搏称为超速抑制。导致这种现象的机制可能与乙酰胆碱释放、钾释放、电生钠泵激活、心输出量和冠状动脉血流量增加、心脏大小减小及随之而来的壁张力降低，以及非缺血心脏中更快心率下兴奋性恢复不均匀性降低有关。起搏的所有这些效应均抑制加速的起搏点活动或防止出现有利于折返运动性心动过速发生的条件。成对、耦合或快速心房起搏可改善心室功能或减慢心室率，或二者兼具，而不消除异位起搏点活动。起搏部位位于心内膜、心外膜、冠状窦、经房间隔或食管位置的心房起搏可中断或预防快速室上性或室性心律失常。同样，在心内膜、心外膜、心肌或经胸部位进行心室起搏可能同样有效。人工起搏几乎可消除每种类型的心动过速。如果要采用电治疗，心室颤动总是需要电击除颤，心房颤动通常也需要，尽管曾有一次报告通过快速起搏使心房除颤。单极或双极起搏器可临时使用，也可在植入后永久使用。用于消除室上性心动过速的起搏频率范围从单个早搏到每分钟3600次的交流电心房起搏。心脏的人工电刺激可以按需进行，也可以是竞争性的（固定频率）。外部磁铁、感应线圈耦合和射频信号可使永久性植入起搏器间歇性地使用竞争性起搏。因此，心脏电起搏是控制快速心率的一项极为重要的技术。
