Coexisting preexcitation syndrome and intermittent heart block presenting as neonatal seizures

An infant presented with neonatal syncope and seizures. An ECG showed a preexcitation pattern, most compatible with Wolff-Parkinson-White (WPW) syndrome. Rhythm monitoring during an event demonstrated prolonged periods of complete AV block with no ventricular escape mechanism. We postulated that ventricular asystole was initiated by mechanical or autonomic influences on the accessory pathway and sustained by electrophysiologic interactions between the accessory pathway and the junctional escape focus. This is the first case report of a newborn having coexisting congenital AV block and WPW syndrome.