• Wolff-Parkinson-White (WPW) syndrome is an inherited disorder in which there is an accessory pathway (Bundle of Kent) that allows impulse propagation from the atria to ventricles and vice versa (recall that normally impulse can only travel from the atria to ventricles via the AV node).
• On ECG, there is delta wave in between P and QRS (due to premature depolarization of the ventricles triggered by the impulses conducted via accessory pathway) and shortened PR (because AV node is bypassed).
• Occasionally, an irritable impulse from rapid-pacing atrial or junctional foci (e.g. SVT) can propagate to the ventricles via the accessory pathway that can degenerate into ventricular arrhythmias.
