Recent developments in the field of electrophysiology and surgical therapy in selected cases of Wolff-Parkinson-White syndrome (W-P-W) support the concept of anomalous A-V pathways. Impulse transmission usually occurs simultaneously through both the normal and anomalous pathways resulting in a fusion QRS complex. Atrial tachycardia is usually due to reentry through the normal and anomalous A-V pathways. However, reentry may occur independently in the A-V node alone exclusive of the anomalous pathway. Anomalous connections, despite varying anatomic locations, may result in similar electrocardiographic manifestations characteristic of W-P-W. His bundle recordings together with electrophysiologic studies may be clinically useful (1) to differentiate various types of anomalous connections, (2) for possible determination of the reentry circuit, (3) to predict the maximum ventricular rate possible during supraventricular tachycardia by evaluating the refractory period of the A-V pathways, or (4) to compare the efficacy of different drugs in a given patient. Surgical interruption of the anomalous pathway in selected cases with W-P-W (type B) is feasible but is most commonly not necessary. The indications for medical and surgical management of symptomatic cases with W-P-W are reviewed.