Role of Implantable Cardioverter-Defibrillators in Patients With Methadone-Induced Long QT Syndrome

Abstract

Patients with methadone-induced long-QT syndrome may experience Torsades de Pointes (TDP) or aborted sudden death requiring the placement of implantable cardioverter-defibrillators (ICDs). Outcomes after ICD implantation in these patients are unknown. Eight patients presenting with methadone-induced long-QT syndrome and episodes of symptomatic TDP were followed after having undergone ICD implantation. The study group included 5 women and 3 men (mean age 48.5 +/- 5 years) receiving methadone doses of 204 +/- 173 mg. All but 1 subject had preserved ventricular function (mean left ventricular ejection fraction 61 +/- 1.1%). All of the patients had prolonged QTc intervals (mean 613 +/- 71 ms) while taking methadone. After ICD implantation, 6 of the 8 patients continued treatment with methadone as a result of intractable dependence. Over a mean follow-up period of 27 months, 1 patient expired from unknown causes. Three of those patients had interrogation-proved ICD shocks for TDP. In conclusion, patients with methadone-induced long-QT syndrome and TDP are at high risk for recurrent arrhythmic events if methadone is continued. This small cohort of patients suggests that ICDs may be lifesaving in those subjects who continue taking methadone after initial episodes of TDP.