Uncertainties about interpretation of ventricular stimulation studies in patients with Wolff-Parkinson-White syndrome.

Arrhythmia is common and important in the Wolff-Parkinson-White syndrome, and indeed many would agree that both pre-excitation and supraventricular arrhythmia are essential features of the classical expression of this syndrome. Reentrant atrioventricular tachycardia is the most commonlyencountered arrhythmia in the syndrome, but atrial fibrillation and to a lesser extent flutter are seen in