WPW

The Wolff Parkinson White syndrome is an abnormality of the hearts electrical system. When the heart beats normally the electrical impulse initiating the heartbeat start at the sinus node and passes through the atrioventricular node to the ventricles. With WPW patients there is extra myocardial tissue present in the atrioventricular ring, this causes a short circuit. This tissue (accessory pathway) passes the electrical signal to the ventricles more quickly than the correct pathway via the AV node. The ventricles are thus pre-excited causing arrhythmia. Generally the QRS complex has a delta wave at the start of the QR upstroke and the PR interval is shorter than normal.