Résumé
There have been many studies of the natural history of the WFW syndrome (4 new cases per 100 000 patient years), showing that the incidence of sudden death is low and that about 30% of initially asymptomatic patients eventually will become symptomatic during follow-up.
The factors associated with ventricular fibrillation are age under 30 years, the association with tachycardias (atrial fibrillation or reciprocating tachycardias) either spontaneous or inducible in asyymptomatic patients, multiple accessory pathways, posteroseptal bundles, atrial vulnerability, short anterograde effective refractory period of the accessory pathway (< 250 ms), and shorter RR intervals in atrial fibrillation. Noninvasive testing has a secondary role in the stratification of risk of sudden death and electrophysiological studies are the key investigations. In young asymptomatic people with WPW, factors such as young age (< 30 years), at risk occupations, sporting activities, short refractory periods and/or inducible tachycardia during electrophysiological testing would be indications for accessory pathway ablation.
Epidemiological data show that in the absence of symptoms the risk of ventricular fibrillation in the long-term is extremely small in an asymptomatic patient in whom the WPW syndrome has been diagnosed. On the other hand, the appearance of symptoms should lead to a reassessment of the question of ablation in a patient in whom the procedure had not been initially indicated.