[Proarrhythmia caused by amiodarone]

A woman with mitral prosthesis, treated with amiodarone i.v. (500 mg in two boluses) for an atrial tachycardia, shows repeated episodes of torsade de pointes. Although there is a connection between the intensity of electro-physiological alterations due to the anti-arrhythmic therapy and pro-arrhythmic effects, there are cases in which the torsade de pointes seems to be associated with modest alterations of QT intervals or even without high plasma concentrations of drugs. In these cases a genetic predisposition for drug's metabolism alteration or greater sensibility of target organs is suggested.