Other rare accessory pathway connections that may participate in reentrant tachycardia are nodofascicular pathways (connecting the AV node to a fascicle) and nodoventricular pathways (connecting the AV node to the ventricular myocardium). Fasciculoventricular pathways, connecting a fascicle to the proximal right or left bundle branch, have also been described, although they have never been reported to participate in tachycardia. An EP study is necessary to establish the diagnosis of these rare accessory pathways. The diagnosis of WPW syndrome is reserved for patients who demonstrate ventricular pre-excitation on their resting ECG that participates in arrhythmias. Rapid anterograde accessory pathway conduction during AF can result in SCD in patients with a manifest acces- sory pathway, with a 10-year risk ranging from 0.15% Unfortunately, SCD may be the first pre- sentation of patients with undiagnosed WPW. Increased risk of SCD is associated with a history of symptomatic tachycardia, multiple accessory pathways, and a shortest pre-excited R-R interval of <250 ms during AF. The risk of SCD associated with WPW appears highest in the first Antiarrhythmic drug treatment of Page et al 2015 ACC/AHA/HRS SVT Guideline e535 patients with orthodromic AVRT can be directed at either the accessory pathway or the AV node, as both are key portions of the reentrant circuit. AV nodal blocking agents may be contraindicated in patients at risk of rapid con- duction down the accessory pathway during AF. Catheter ablation strategies target the accessory pathway, with high success rates. 6.1. Management of Patients With Symptomatic Manifest or Concealed Accessory Pathways See Figure 14 for the algorithm for acute treatment of ortho- dromic AVRT and Figure 15 for the algorithm for ongoing management of orthodromic AVRT. 6.1.1. Acute Treatment: Recommendations Recommendations for Acute Treatment of Orthodromic AVRT COR LOE Recommendations I B-R 1. 