Sudden death risk associated with asymptomatic Wolff-Parkinson-White syndrome

Abstract

First described in 1930, the Wolff Parkinson White (WPW) syndrome has the accessory pathway as anatomical and electric substrate for different types of arrhythmia. In 1979 sudden cardiac death associated with WPW was mentioned for the first time. The mechanism by which sudden death occurs is atrial fibrillation conducted rapidly over the accessory pathway or pathways with a short effective antegrade refractory period (EARP) that deteriorates into ventricular fibrillation. When WPW syndrome is associated with tachycardia, it is a good scenario, because the patient can figure out the presence of the accessory pathway and can at least evaluate it by electrophysiological study or treat it by radiofrequency catheter ablation.
We present the case of a medical school student, totally asymptomatic, who was randomly diagnosed with WPW syndrome during the clinical practice in the cardiology service, being volunteer for an electrocardiogram. The patient requested electrophysiological study after the steps of the procedure were properly explained. The study revealed the great risk of sudden death as during the procedure atrial fibrillation conducted over a short AERP accessory pathway was easily induced and degenerated into ventricular fibrillation. Five external electrical conversions and the rapid infusion of Amiodarone were needed to return and maintain the sinus rhythm. The catheter ablation of the accessory pathway was performed. During time, a number of risk factors for sudden death associated with WPW were found as follows: shortest preexcited RR interval during and its surrogate, the antegrade ERP of the accessory pathway; multiple accessory pathways; male gender and syncope.

Key words:

Wolff-Parkinson-White syndrome, sudden death, syncope, electrophysiological study, catheter ablation, atrial fibrillation