Methadone-related QT prolongation and arrhythmic storm in an addicted patient: What weapons to use in a lost war?

Drug-induced QT prolongation is a common finding in patients on therapy with antidepressants, antipsychotic, diuretics, antiarrhythmic drugs, etc. Drug's interruption normally restored QT interval. A 50-year-old man, with a history of abuse of heroin in treatment with methadone, was admitted in our department for syncope. He made occasional abuse of cocaine. On the day before he had vomited and diarrhea. The electrocardiogram showed sinus bradycardia and a prolonged corrected QT interval. Serum potassium levels resulted quite low. During the ECG monitoring, multiple torsade de pointes degenerating in ventricular fibrillation with loss of consciousness occurred (treated with prompt DC-shock). Infusion of isoproterenol was undertaken resulting in suppression of ventricular arrhythmias. Considering the possibility of failure of opioid's replacement and the unknown genetic substrate of the QT prolongation, ICD implantation was performed. Management of patients with methadone-related QT prolongation is not simple, mainly due to difficulty in replacing or sudden interruption of this drug. Isoproterenol infusion is a good choice in the acute setting. In the long term, ICD is probably an appropriate therapy in order to prevent sudden death in this particular population. Frequent ECG monitoring is useful to prevent QT prolongation and arrhythmic risk in patients treated with methadone.