Abstract In Wolff-Parkinson-White (WPW) syndrome, the ventricles are pre-excited through an accessory conduction pathway, bundle of Kent, which directly connects atria with ventricles bypassing the atrioventricular node. The altered sequence of ventricular activation secondary to presence of the bundle of Kent may cause pseudo myocardial infarction and pseudo ventricular hypertrophy patterns on electrocardiogram. The morphology of these pseudo electrocardiographic patterns depends on the anatomical location of the bundle of Kent around the circumference of the atrioventricular ring. Electrocardiograms of the WPW syndrome displaying morphology of different pseudo patterns are presented and the mechanisms causing pseudo patterns are reviewed. (Am J Emerg Med 2000;18:802-806.