Surawicz B, Knoebel S B
J Am Coll Cardiol. 1984 Aug;4(2):398-413. doi: 10.1016/s0735-1097(84)80232-6.
A survey of current literature suggests an increasing interest in both the desirable and undesirable implications of a prolonged QT interval, the former perceived to be the beneficial effect of antiarrhythmic drugs that prolong the duration of ventricular action potential, and the latter considered to be a potential marker for sudden cardiac death in patients with ischemic heart disease. In addition, there has been an increasing interest in the congenital long QT syndrome associated with an apparent dysfunction of the autonomic nervous system and serious, potentially lethal ventricular arrhythmias. Circumstantial evidence suggests that these arrhythmias are due to increased dispersion of repolarization which may be aggravated by psychologic and emotional perturbations. In this review, the associations between the long QT interval, autonomic nervous system, dispersion of repolarization, antiarrhythmic drugs and ventricular arrhythmias are examined. Attention is directed to the difficulties of accurate QT measurement, problems related to the correction of the QT interval for heart rate and sex (QTc), the wide range of normal values and the modest QT alterations after various manipulations of the autonomic nervous system. Clinical conditions associated with marked, moderate and occasional QT lengthening are listed and discussed briefly in relation to the disturbances of nervous system, dispersion of ventricular repolarization and ventricular arrhythmias. It is proposed that the absence of relevant animal models of neurogenic or psychogenic QT prolongation hinders the investigation of the neurogenic factors associated with QT lengthening. QT prolongation is most often induced by antiarrhythmic drugs and ischemic heart disease. However, it is not known whether the occurrence of torsade de pointes type of ventricular tachycardia in patients treated with antiarrhythmic drugs is related to a critical drug dose or a critical degree of QTc prolongation. There is no conclusive evidence that QT lengthening has any predictive value either during the acute phase or during convalescence after myocardial infarction. Also, a serious deficiency in current knowledge is the lack of an established relation between the prolonged QT interval and the dispersion of ventricular repolarization. It is concluded that the number of unanswered questions discussed in this review still makes it difficult to judge when a prolonged QT interval is good, bad or indifferent.
对当前文献的一项调查表明，人们对QT间期延长的有利和不利影响越来越感兴趣，前者被认为是延长心室动作电位持续时间的抗心律失常药物的有益作用，后者被认为是缺血性心脏病患者心脏性猝死的潜在标志物。此外，人们对与自主神经系统明显功能障碍和严重的、潜在致命的室性心律失常相关的先天性长QT综合征也越来越感兴趣。间接证据表明，这些心律失常是由于复极离散增加所致，心理和情绪波动可能会加重这种情况。在这篇综述中，研究了长QT间期、自主神经系统、复极离散、抗心律失常药物和室性心律失常之间的关联。重点关注了准确测量QT的困难、与心率和性别校正QT间期（QTc）相关的问题、正常数值范围以及自主神经系统各种操作后QT的适度改变。列出并简要讨论了与显著、中度和偶尔QT延长相关的临床情况，涉及神经系统紊乱、心室复极离散和室性心律失常。有人提出，缺乏神经源性或精神源性QT延长的相关动物模型阻碍了对与QT延长相关的神经源性因素的研究。QT延长最常见的诱因是抗心律失常药物和缺血性心脏病。然而，尚不清楚接受抗心律失常药物治疗的患者发生尖端扭转型室性心动过速是否与临界药物剂量或QTc延长的临界程度有关。没有确凿证据表明QT延长在心肌梗死急性期或恢复期具有任何预测价值。此外，目前知识的一个严重不足是，长QT间期与心室复极离散之间缺乏既定关系。结论是，本综述中讨论的未解决问题的数量仍然使得难以判断QT间期延长何时是好的、坏的或无关紧要的。
