Dudley White described a case series of 11 patients with a syndrome that now bears their name. 1 The first patient with a short PR interval, ventricular preexcitation, and supraventricular tachycardia was described by Cohn and Fraser in 1913. 1 Wood et al postulated the accessory pathway (AP) as its anatomic substrate in 1942, and a large population series reported the prevalence of preexcitation to be 0. 15% in 1962. 2 Reports in 1971 and 1979 described sudden cardiac death (SCD) in patients with Wolff-Parkinson-White (WPW) syndrome related to atrial fibrillation (AF) that was conducted rapidly over the AP with a short refractory period that deteriorated into ventricular fibrillation (VF). 3,4 The first operative ablation of an AP was performed by Sealy in 1967, 1 whereas Weber and Schmitz described the first endocardial catheter ablation of an AP in 1983. 1 The evolution of curative catheter ablation has clearly become the treatment of choice in the patient with substantive symptoms. A continuing controversy has been the use of this therapy in the asymptomatic or less symptomatic individual, and the central looming theme is the incidence of SCD as part of the natural history of this entity and our ability to predict it. The incidence of SCD in symptomatic patients with WPW syndrome was initially reported in the late 1960s and is estimated to be in the range of 0.25% per year, or 3% to 4% over a lifetime. 5
Article see p 661A number of risk factors for development of SCD have emerged, 6 including (1) shortest preexcited RR interval (SPRRI) during AF 4 and its surrogate, the antegrade effective refractory period (ERP) of the AP; (2) multiple APs; (3) male gender 7 ; (4) a history of or inducibility of atrioventricular reentrant tachycardia (AVRT); (5) age; and (6) syncope.In a large, early series of patients resuscitated from VF related to WPW syndrome, a SPRRI of Ͼ250 ms was not observed, and a range of 200 ms or less was the norm. 4 Most patients in this series had inducible AVRT, and others reported vulnerability to AF and inducible AVRT as risk factors. 7 Although a SPRRI Ͻ250 ms has been virtually uniformly present in patients with VF, many more patients never destined to have sudden death also have this risk factor, which gives it a poor positive predictive value (PPV) with a high negative predictive value (NPV). 8 Thus, a SPRRI of Ͻ250 ms and its surrogate, an antegrade ERP of Ͻ250 ms, have virtually 100% NPV but poor PPV. 9 A SPRRI Ͻ250 ms remains the pivotal risk factor without which VF related to AF would be rare indeed. Requiring the presence of multiple risk factors in combination would be expected to improve specificity but at the risk of loss of sensitivity.The only uncontestable and meaningful end point for accurate risk assessment is the SCD rate, which fortunately is very low. Nonetheless, this low event rate challenges the accuracy of any predictor, including electrophysiological studies. A high NPV reported for risk stratifiers is not meaningful in this context, and it must be borne in min...