Torsades de pointes, which may be a life-threatening arrhythmia is usually defined as polymorphic ventricular tachycardia developing in association with prolongation of the QT interval. Prolongation of the QT interval may be congenital as well as acquired due to various reasons including drug effects or electrolyte disorders. Torsades de pointes resulting from electrolyte abnormality is reportedly due to chronic hypocalcemia, hypokalemia or hypomagnesemia. Torsades de pointes resulting from rapid-onset isolated hypokalemia in childhood has not yet been reported. We herein report a case with torsades de pointes developing secondary to rapid-onset isolated hypokalemia in the presence of acute myelogenous leukemia and severe pneumonia in whom rapid infusion of potassium restored the QT interval to normal and eliminated the torsades de pointes.
Isolated hipokalemia, long QT syndrome, ventricular tachycardia