Mexiletine: long-term follow-up of a patient with prolonged QT interval and quinidine-induced torsades de pointes.

The use of class 1A antidysrhythmic agents in patients with or without prolonged QT intervals carries a risk of induction of polymorphic ventricular tachycardia. The class 1B antidysrhythmics have many similarities to the former group, but have different modes of action and electrophysiologic properties. Therefore, lidocaine and lidocaine-like drugs such as mexiletine may be used with relative safety in this clinical situation, as in the case we have reported, in which lidocaine and mexiletine controlled VPB in the acute stage and during long-term follow-up respectively, while quinidine induced "torsades de pointes."