Electrophysiologic studies of Jervell, Lange-Nielsen syndrome

Electrophysiologic studies were performed in two sibling with Jervell, Lange-Nielsen syndrome. Electrophysiologic parameters were all within normal limits except for prolongation of effective refractory period of the ventricular myocardium. This finding may suggest one of electrophysiologic mechanisms underlying QT prolongation, that is, delayed ventricular repolarization.