Torsades de Pointes During Methadone Treatment

Four patients (3 men, 1 woman) with no known history of heart disease were seen in the emergency room for syncopal episodes (Table). All were under longterm methadone therapy, although only 1 was receiving >200 mg/day. Three of these patients were infected with human immunodeficiency virus (HIV), but only 1 was on antiretroviral therapy. The electrocardiographic recordings and monitoring showed sinus rhythm, prolonged corrected QT interval, and runs of self-limiting TdP polymorphic ventricular tachycardia (Figure 1), which degenerated to ventricular fibrillation in 2 cases, requiring electrical cardioversion. The biochemical parameters showed low serum potassium concentrations in 2 cases, whereas calcium and magnesium levels were normal in all patients. In addition, various toxic substances were detected in urine. The echocardiogram showed severe biventricular dysfunction in 1 of the patients; ventricular function was normal in all others. After methadone was discontinued and magnesium sulfate, isoproterenol perfusion, and potassium supplements were started, polymorphic ventricular tachycardia disappeared within 7 hours of admission. After 2-3 days, methadone treatBR I E F RE P O RT S