Wolff-Parkinson-White syndrome: illustrative case and brief review.

The Wolff-Parkinson-White syndrome (WPWS) is a pre-excitation syndrome manifested on the 12-lead ECG by a short PR interval (less than .12 sec), a prolonged QRS interval (greater than .10 sec), and an initial slurring of the QRS complex called a delta wave. The anatomical etiology is the presence of accessory atrioventricular conduction fibers called the Kent bundle. Patients with the WPWS may present to the emergency department with a wide spectrum of symptoms, ranging from mild palpitations, to unstable tachydysrhythmias and sudden cardiac death. WPWS should be suspected in any patient presenting with a tachydysrhythmia with a rate exceeding 200/minute. Cardioversion is indicated in the unstable patient. It is impossible to predict the effect of any particular drug without prior electrophysiologic studies in a patient with WPWS. Procainamide is the safest drug for the stable WPWS patient with a tachydysrhythmia, including wide-complex and irregular rhythms. Verapamil is a useful drug in narrow-complex, regular rhythms, although complications have been reported. Atrial fibrillation may be difficult to diagnose in a very rapid tachycardia, and the use of verapamil in WPWS with atrial fibrillation is contraindicated. Electrophysiologic studies are indicated in the WPWS patient to maximize prophylactic therapy. An illustrative case as well as pathophysiology and management of WPWS are discussed.