[Arrhythmogenic effect of flecainide--treatment with i.v. magnesium]

We report on a 46-year-old woman with ventricular tachycardia and ventricular fibrillation after starting antiarrhythmic drug therapy with flecainide. The flecainide acetate plasma levels were always in the normal range. A successful therapeutical intervention was induced with two i.v. applications of 1,000 mg magnesium glutamate. A persistent suppression of ventricular rhythm disturbance was accomplished by continuous i.v. application of 4 mg magnesium glutamate/min.