药源性尖端扭转性室速的发生机制及防治

药源性尖端扭转性室速（TdP）是主要的获得性TdP之一，临床发病率较低，但致死性高。药物阻断Ikr引起QT间期延长是药源性TdP的重要机制；女性、电解质平衡紊乱、心脏及脑损伤等基础疾病、同时应用可延长QT间期的多种药物、代谢竞争引起药物蓄积是TdP的易感因素；引起TdP的常见药物有Ⅰa类和Ⅲ类抗心律失常药物、抗精神病药物、抗组胺药、大环内酯类抗生素、氟喹诺酮类抗茵药物及西沙必利、三氧化二砷、美沙酮等药物；药源性TdP治疗措施包括停用可引起QT间期延长的药物，静脉给予硫酸镁治疗，血钾应维持在较高水平，对于血流动力学不稳定者给予非同步直流电除颤。

Drug-Induced Toesades de Pointes

Most of acquired torsades de pointes （TdP） are drug- induced torsades de pointes. Although the incidence of drug- induced TdP is rare, the mortality of drug- induced TdP is high. We review the mechanisms, predispositions, culprit agents, prevention and management of TdP. All patients have more than one of risk factors, including female sex, structural heart disease, hypokalemia, multiple QT prolonging drugs or agents interfering with their metabolism. Implicated drugs include class Ⅰa and Ⅲ antiarrhythmics, antipsychotics, histamine 1 receptor antagonists, macrolide antibiotics, fluoroquinolones, cisapride, arsenic trioxide and methadone. Treatment for TdP includes intravenous magnesium sulfate and immediate defibrillation for hemodynamic instability. Potassium levels should be maintained in the normal range and all QT prolonging agents must be promptly discontinued.