Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Weizmann St 6, Tel Aviv-Yafo 6423906, Israel.
Department of Cardiology, Assuta Ashdod University Hospital, Ha-Refu'a St 7, Ashdod 7747629, Israel.
Eur Heart J. 2021 Oct 7;42(38):3965-3975. doi: 10.1093/eurheartj/ehab138.
Distinctive types of polymorphic ventricular tachycardia (VT) respond differently to different forms of therapy. We therefore performed the present study to define the electrocardiographic characteristics of different forms of polymorphic VT.
We studied 190 patients for whom the onset of 305 polymorphic VT events was available. The study group included 87 patients with coronary artery disease who had spontaneous polymorphic VT triggered by short-coupled extrasystoles in the absence of myocardial ischaemia. This group included 32 patients who had a long QT interval but nevertheless had their polymorphic VT triggered by ectopic beats with short coupling interval, a subcategory termed 'pseudo-torsade de pointes] (TdP). For comparison, we included 50 patients who had ventricular fibrillation (VF) during acute myocardial infarction ('ischaemic VF' group) and 53 patients with drug-induced TdP ('true TdP' group). The QT of patients with pseudo-TdP was (by definition) longer than that of patients with polymorphic VT and normal QT (QTc 491.4 ± 25.2 ms vs. 447.3 ± 55.6 ms, P < 0.001). However, their QT was significantly shorter than that of patients with true TdP (QTc 564.6 ± 75.6 ms, P < 0.001). Importantly, the coupling interval of the ectopic beat triggering the arrhythmia was just as short during pseudo-TdP as during polymorphic VT with normal QT (359.1 ± 38.1 ms vs. 356.6 ± 39.4 ms, P = 0.467) but was much shorter than during true TdP (581.2 ± 95.3 ms, P < 0.001).
The coupling interval helps discriminate between polymorphic VT that occurs despite a long QT interval (pseudo-TdP) and polymorphic arrhythmias striking because of a long QT (true TdP).
不同类型的多形性室性心动过速（VT）对不同形式的治疗反应不同。因此，我们进行了本研究，以确定不同形式的多形性 VT 的心电图特征。
我们研究了 190 名患者，他们的 305 次多形性 VT 发作起始时间可用。研究组包括 87 名患有冠状动脉疾病的患者，他们在没有心肌缺血的情况下，由短联律间期的短偶联期外收缩触发自发性多形性 VT。该组包括 32 名 QT 间期延长但多形性 VT 仍由短联律间期的异位搏动触发的患者，这一分支称为“假性尖端扭转型室速（TdP）”。为了比较，我们包括 50 名在急性心肌梗死后发生心室颤动（“缺血性 VF”组）的患者和 53 名药物诱导的 TdP 患者（“真正的 TdP”组）。假性 TdP 患者的 QT（根据定义）长于多形性 VT 和正常 QT 患者（QTc 491.4±25.2 ms 与 447.3±55.6 ms，P<0.001）。然而，他们的 QT 明显短于真正的 TdP 患者（QTc 564.6±75.6 ms，P<0.001）。重要的是，触发心律失常的异位搏动的偶联间期在假性 TdP 中与多形性 VT 伴正常 QT 时一样短（359.1±38.1 ms 与 356.6±39.4 ms，P=0.467），但明显短于真正的 TdP（581.2±95.3 ms，P<0.001）。
偶联间期有助于区分尽管 QT 间期延长但仍发生的多形性 VT（假性 TdP）和由于 QT 间期延长而发生的多形性心律失常（真正的 TdP）。
