DEFINITION
Ventricular preexcitation occurs when impulses originating in the sinoatrial node or atrium activate a portion of the ventricles prematurely through an accessory pathway without going through the AV node; the remainder of the ventricles is activated normally through the usual conduction system.
WPW syndrome consists of ventricular preexcitation with episodes of paroxysmal supraventricular tachycardia.
