[Therapeutic management of the Wolff-Parkinson-White syndrome]

Reentry tachycardia and atrial fibrillation occur in 12 to 36 per cent of patients with Wolff-Parkinson-White (WPW) syndrome. The severity of the arrhythmia depends on the frequency of attacks, on the heart rate in tachycardia and on the condition of the underlying myocardium. Moreover, ventricular fibrillation has been observed in some cases of atrial fibrillation with a fast ventricular response due to accessory pathways with very short refractory periods. This is the mechanism of sudden death in WPW syndrome. The prognosis can be assessed by atrial pacing, now often performed by the transoesophageal method. pacing makes it possible to measure the atrial vulnerability and the value of the shortest interval conducted through the accessory pathway. Indirect methods, such as exercise electrocardiogram or ajmaline injection, are less specific in predicting the characteristics of the accessory pathway. The therapeutic approach depends on the symptoms. Asymptomatic patients or those who present with only rare episodes of reciprocal tachycardia can be left untreated, but a preventive medical treatment is necessary in patients with atrial fibrillation or frequent attacks of tachycardia. When this treatment is ineffective or complicated by side-effects, a more radical therapy must be proposed. For the last 20 years this has been surgery, but nowadays catheter ablation of the accessory pathway gives similar results in skilled hands and tends to replace surgery.