长QT综合征发生尖端扭转型室性心动过速时初始节律的研究

目的 比较先天性与获得性长QT综合征（LQTS）发生尖端扭转型室性心动过速（TdP）时的初始节律.方法分析6例先天性LQTS、8例获得性LQTS的Q-TC间期、校正的Tp-e间期（Tp-eC）及TdP发生阵数、初始节律.结果6例先天性LQTS中,Q-TC间期（565.2± 45.1）ms,Tp-eC（145.1±29.1）ms,共计Tdp14阵,平均2.3阵/例,TdP发作前可见窦性节律加快、频发室性期前收缩或室性心动过速.8例获得性LQTS中,Q-TC间期（591.3±67.3）ms,Tp-eC（154.2±56.9）ms,共计TdP237阵,平均29.6阵/例,TdP发生在缓慢节律的基础上频发室性期前收缩,呈短-长-短形式触发.结论获得性LQTS比先天性LQTS更具有危险性,TdP发生前的初始节律分析有助于鉴别先天性LQTS和获得性LQTS及指导临床治疗.     

CSAHi study: Validation of multi-electrode array systems (MEA60/2100) for prediction of drug-induced proarrhythmia using human iPS cell-derived cardiomyocytes -assessment of inter-facility and cells lot-to-lot-variability-

In vitro screening of hERG channels are recommended under ICH S7B guidelines to predict drug-induced QT prolongation and Torsade de Pointes (TdP), whereas proarrhythmia is known to be evoked by blockage of other ion channels involved in cardiac contraction and compensation mechanisms. A consortium for drug safety assessment using human iPS cells-derived cardiomyocytes (hiPS-CMs), CSAHi, has been organized to establish a novel in vitro test system that would enable better prediction of drug-induced proarrhythmia and QT prolongation. Here we report the inter-facility and cells lot-to-lot variability evaluated with FPDc (corrected field potential duration), FPDc₁₀ (10% FPDc change concentration), beat rate and incidence of arrhythmia-like waveform or arrest on hiPS-CMs in a multi-electrode array system.Arrhythmia-like waveforms were evident for all test compounds, other than chromanol 293B, that evoked FPDc prolongation in this system and are reported to induce TdP in clinical practice. There was no apparent cells lot-to-lot variability, while inter-facility variabilities were limited within ranges from 3.9- to 20-folds for FPDc₁₀ and about 10-folds for the minimum concentration inducing arrhythmia-like waveform or arrests.In conclusion, the new assay model reported here would enable accurate prediction of a drug potential for proarrhythmia.     

Recurrent Torsade de Pointes type ventricular tachycardia in intracranial hemorrhage

Two out of 72 cases of intracranial hemorrhage-induced polymorphous ventricular tachycardia with typical Torsade de Pointes morphology are presented. Bot patients had marked QT_c prolongation more than 550 ms. In one patient (QT_c: 669 ms) Torsade de Pointes degenerated into fatal ventricular fibrillation. Even though polymorphous Torsade de Pointes type ventricular tachycardia is rare during the clinical course of intracranial hemorrhage, attention should be given to the QT interval. QT_c prolongation more than 550 ms may carry a high risk of Torsade de Pointes type ventricular tachycardia and ventricular fibrillation.     

Male pseudohermaphroditism presented with sudden cardiac arrest

Torsades de pointes is a life-threatening arrhythmia associated with a number of causes, but is very rare among endocrinologic disorders. We report a case of male pseudohermaphroditism with hyperaldosteronism due to a 17α-hydroxylase deficiency presented with sudden cardiac arrest.