Treatment is based on the risk stratification of the individual. Risk stratification is performed to determine which individuals with WPW syndrome are at risk for sudden cardiac death (SCD). Sudden cardiac death in these individuals is due to the propagation of an atrial arrhythmia to the ventricles at a very high rate. Noninvasive tests have a 70% positive predictive value and 30% negative predictive value for identifying pathways with life-threatening properties.Electrophysiologic studies are useful for evaluation of patients’ symptoms.

• Low-risk patients for life-threatening arrhythmia over the accessory pathway during AF include the following:^[1]

• Abrupt loss of conduction over the pathway during exercise test in sinus rhythm
• Intermittent loss of preexcitation during EKG or ambulatory monitoring

• High-risk patients for life-threatening arrhythmia in the electrophysiologic study include the following:

• R-R interval<250 ms between two pre-excited complexes during induced AF
• The presence of multiple accessory pathways
• The finding of AVRT precipitating pre-excited AF
• Accessory pathway refractory period<240 ms