氟喹诺酮类药物所致尖端扭转型室性心动过速

Fluoroquinolone-induced torsade de pointes

氟喹诺酮类常用药物中左氧氟沙星、环丙沙星、加替沙星和莫西沙星等可以引起尖端扭转型室性心动过速(TdP)。TdP的临床表现为眩晕、昏厥甚至心搏停止,心电图可见QT间期延长及TdP。其发生机制尚不明确,可能与抑制心肌细胞K+离子通道,使K+外流受阻有关。氟喹诺酮类常用药物所致TdP的危险因素有女性、高龄、器质性心脏病(特别是充血性心力衰竭、QT间期延长、心动过缓)、肝肾功能损害、低钾低镁血症,以及合用可以引起QT间期延长的药物等。一旦患者出现QT间期延长及TdP应立即停药,补充钾和镁抑制早期后除极,也可采用人工临时心脏起搏或异丙肾上腺素提高基础心率。意识丧失和心室颤动者,可进行体外电复律。

Fluoroquinolone antibacterials levofloxacin,ciprofloxacin,gatifloxacin and moxifloxacin have been reported to cause torsades de pointes（TdP）.Clinical manifestations of TdP are dizziness,fainting,or even cardiac arrest.QT interval prolongation and TdP are visible on the electrocardiogram（ECG）.The mechanism of TdP is unclear,it may be associated with inhibition of cardiac K＋ channels and blocking of K＋ outflow.The risk factors for causing TdP are female,advanced age,underlying organic heart disease（especially congestive heart failure,QT interval prolongation and bradycardia）,liver and kidney dysfunction,hypokalemia,and hypomagnesemia,as well as combined use with other drugs that can cause QT interval prolongation.Once a patient develops to QT interval prolongation and TdP,the causative agent should be discontinued immediately.Potassium and magnesium supplements are given to inhibit the early after-depolarization.Artificial temporary cardiac pacing or isoprenaline is used to maintain normal heart rate.For the unconscious patient with ventricular fibrillation,external electrical cardioversion could be carried out.