In the normal heart, the AV node is the only electrical connection between the atria and ventricles. With WPW, the heart has an extra electrical conduction pathway  ( extra "wire" or "nerve" ) which we call an " accessory pathway" that electrically connects the atrium to the ventricle. It is present from birth but may not detected or cause any problems with tachycardia until later in life. Many WPW patients may never experience heart problems related to this abnormal pathway and may not even know they have until it is detected on an electrocardiogram often done for an unrelated reason. This pathway is in the wall of the heart at the junction of the atria ( upper chambers) and ventricles ( lower chambers and can be located virtually anywhere on the circumference of the heart ( at level of the "atrioventricular rings". An individual may  have more than one accessory pathway.

People with WPW may experience tachycardia attacks because the electrical impulse gets "trapped" in an electrical circuit that travels in a large circle between the normal AV node and the accessory pathway. This can cause the heart to race up to 150 - 300 beats per minute. The tachycardia attacks start suddenly without warning and there is often no obvious cause. The feeling of the heart pounding in the chest or neck can be associated with lightheadedness, chest pain and sometimes a blackout. Rarely, WPW can cause the heart to race rapidly and dangerously out of control during an arrhythmia called atrial fibrillation.

Wolf-Parkinson-White

Catheter ablation of WPW syndrome involves destroying the accessory pathway. The EP study determines the number of extra pathways and the location of each. The ablation catheter is then inserted and used to carefully map the heart to precisely locate each pathway. When  the catheter is optimally positioned against such a  pathway, ablation energy is delivered. This creates a very small scar in the order of millimeters in diameter that destroys the ability of the pathway to create arrhythmias.

Although in general very safe  , there is the potential for complications and these should be discussed beforehand with your doctor.