Wolff-Parkinson-White Syndrome and Isoproterenol Testing in Children

Abstract

Wolff-Parkinson-White syndrome (WPW) is the most common indication for invasive cardiac catheterization and electrophysiological testing in children. There are presently 2 predominant reasons for this. First, patients with WPW are, as the original 1930 investigators so eloquently pointed out, at risk for “paroxysmal tachycardia.”1 Supraventricular tachycardia is typically either orthodromic or, less commonly, antidromic reentrant tachycardia and can cause recurrent and debilitating symptoms. Present-day ablation techniques provide the promise of a cure for WPW in as many as 90% to 100% of patients who undergo this procedure with relatively low risk.2,3 Multiple studies have demonstrated the many medical, psychological, and financial benefits of ablation in the symptomatic WPW child.4–6 Article see p 73 The second reason that children with WPW undergo invasive catheterization and electrophysiological testing is to assess the risk of dying of ventricular fibrillation. The risk of sudden cardiac death in WPW in the pediatric population is, unfortunately, not known, and because of this, estimates of this risk have varied widely and range from 1% over a patient's lifetime to 0.0015 per patient-year.7,8 The reasons for not knowing this figure are myriad but ultimately stem from an inability to adequately identify both the numerator and denominator of WPW patients when creating these sorts of calculations. However, it would be fair and true to state that most authorities believe sudden cardiac death to be a rare event in both children and adults with WPW, especially in those patients who are asymptomatic. Thus, for the symptomatic child with WPW, most are in agreement that ablation, given the correct patient age, size, and history, is both appropriate and probably recommended in the majority of cases.9 However, the asymptomatic child with WPW poses significant problems for the pediatric electrophysiologist. …