Marstrand Peter, Christensen Alex Hørby, Bartels Emil Daniel, Theilade Juliane
Department of Cardiology, Herlev-Gentofte Hospital, University Hospital Copenhagen, Herlev Ringvej 75, Copenhagen, Denmark.
Department of Cardiology, Rigshospitalet, University Hospital Copenhagen, Denmark.
Eur Heart J Case Rep. 2018 Sep 26;2(4):yty106. doi: 10.1093/ehjcr/yty106. eCollection 2018 Dec.
Prolongation of the QT interval on the electrocardiogram is clinically important due to the association with an increased risk of sudden cardiac death. A long QT interval may be genetically determined (congenital long QT syndrome) or be drug-induced long QT syndrome e.g. caused by pharmaceutical drugs and electrolyte imbalances.
In this report, we describe the case a 54-year-old woman, who presented with syncope. At presentation, the QTc interval was markedly prolonged, and she was admitted for observation under telemetry. The following day the patient had experienced a near syncope during an episode of 18 s of Torsade de Pointes (TdP). At the time of TdP, the potassium level (3.4 mmol/L) was mildly reduced, and the ECG showed a QTc interval of 640 ms. In spite of correction of hypokalaemia and discontinuation of the possibly LQTS-inducing drug citalopram the QTc duration remained intermittently prolonged. A transthoracic echocardiogram and a recent coronary angiogram were normal. The patient received an implantable cardioverter-defibrillator. Subsequent genetic testing identified a heterozygous KCNE1 p.D85N (c.253G>A) variant, a known QT modifier with a population prevalence of 1.3%.
We conclude that the combination of a commonly prescribed antidepressant, discrete hypokalaemia, and a common KCNE1 QT modifier may cause severe QTc prolongation and life-threatening arrhythmia.
心电图上QT间期延长具有临床重要性，因为它与心脏性猝死风险增加相关。长QT间期可能由遗传决定（先天性长QT综合征），或由药物引起的长QT综合征，例如由药物和电解质失衡导致。
在本报告中，我们描述了一名54岁女性患者，她因晕厥就诊。就诊时，QTc间期明显延长，她被收入院进行遥测观察。第二天，患者在一次持续18秒的尖端扭转型室性心动过速（TdP）发作期间发生了近似晕厥。在TdP发作时，血钾水平（3.4 mmol/L）轻度降低，心电图显示QTc间期为640毫秒。尽管纠正了低钾血症并停用了可能诱发长QT综合征的药物西酞普兰，但QTc时长仍间歇性延长。经胸超声心动图和近期冠状动脉造影检查均正常。患者接受了植入式心脏复律除颤器。随后的基因检测发现了一个杂合的KCNE1 p.D85N（c.253G>A）变异，这是一种已知的QT修饰因子，在人群中的患病率为1.3%。
我们得出结论，一种常用的抗抑郁药、轻微低钾血症和一种常见的KCNE1 QT修饰因子相结合，可能会导致严重的QTc延长和危及生命的心律失常。
