Soffer J, Dreifus L S, Michelson E L
Am J Cardiol. 1982 Jun;49(8):2021-9. doi: 10.1016/0002-9149(82)90224-7.
Polymorphous ventricular tachycardia may occur in the setting of either a normal or a prolonged Q-T interval. Torsade de pointes is a form of polymorphous ventricular tachycardia in which the polarity of the QRS complex exhibits phasic alterations in both axis and rate. Traditionally, torsade de pointes has been described in association with a variety of congenital and acquired (including drug and metabolic) causes of Q-T prolongation. The distinction between torsade de pointes and those polymorphous ventricular tachycardias occurring in patients with a normal Q-T interval has important therapeutic implications. The former requires strict avoidance of all drugs that may potentially further delay repolarization, including class I antiarrhythmic agents; immediately, the initiation of cardiac pacing is often necessary for control of arrhythmia, and on a long-term basis, sympathetic nervous blockade is often efficacious. In contrast, the polymorphous ventricular tachycardias with a normal Q-T interval usually respond to conventional therapy, including administration of class I antiarrhythmic agents. Thus, the management of polymorphous ventricular tachycardia should be based on the presence of absence of associated repolarization rather than on the morphologic features of the tachycardia. Unfortunately, recent advances in basic and clinical electrophysiology have not yet elucidated the pathophysiologic basis for these arrhythmias, although this is an area of active investigative interest.
多形性室性心动过速可发生于Q-T间期正常或延长的情况下。尖端扭转型室速是多形性室性心动过速的一种形式，其QRS波群的极性在电轴和频率上均呈现阶段性改变。传统上，尖端扭转型室速与多种先天性和后天性（包括药物和代谢性）导致Q-T间期延长的原因有关。尖端扭转型室速与Q-T间期正常患者发生的多形性室性心动过速之间的区别具有重要的治疗意义。前者需要严格避免使用所有可能进一步延迟复极的药物，包括I类抗心律失常药物；立即进行心脏起搏通常是控制心律失常所必需的，长期而言，交感神经阻滞往往有效。相比之下，Q-T间期正常的多形性室性心动过速通常对包括使用I类抗心律失常药物在内的传统治疗有反应。因此，多形性室性心动过速的治疗应基于是否存在相关的复极异常，而非基于心动过速的形态学特征。不幸的是，尽管这是一个积极研究的领域，但基础和临床电生理学的最新进展尚未阐明这些心律失常的病理生理基础。
