[Proarrhythmic effect of ajmaline in idiopathic ventricular tachycardia].

A 23-year-old woman was hospitalized because of life-threatening monomorphic ventricular tachycardia (VT) of 150 beats/min. An intravenous bolus of lidocaine was without effect but 25 mg ajmaline converted the tachycardia to sinus rhythm. A total of 70 mg ajmaline was subsequently infused because of frequent ventricular premature systoles. During this treatment polymorphic VT with very wide QRS complexes developed, but spontaneously disappeared after ajmaline had been discontinued. The case demonstrates the need for taking into account the potential risk of a proarrhythmic effect of anti-arrhythmic drugs.