Atypical Pre-excitation Pattern in Asymptomatic Wolff-Parkinson-White—A Hallmark for High Risk?

Abstract Introduction Delta wave morphology during sinus rhythm on 12 lead ECG usually allows for a relatively precise prediction of the anatomic location of an accessory pathway (AP) provided that the rhythm is fully pre-excited. However, the pre-excitation pattern during sinus rhythm usually offers little information about sudden cardiac death (SCD) risk in adult patients with asymptomatic Wolf-Parkinson-White (WPW). Case Presentation A 42-year-old policeman was referred for an asymptomatic WPW pattern with an unusual delta wave. Initial mapping showed that atrio-ventricular (A-V) fusion on the lateral mitral annulus and radiofrequency (RF) ablation induced a shift in the pre-excitation pattern. Re-mapping identified A-V fusion on the left postero-septal area. Another RF application eliminated pre-excitation. Re-mapping identified A-V fusion on the postero-septal aspect of the mitral annulus and another RF application almost instantaneously induced an A-V split and loss of pre-excitation. Post-ablation testing proved normal anterograde A-V conduction without pre-excitation and no ventriculo-atrial conduction. Serial ECGs proved the persistent loss of pre-excitation at one-month of follow-up. Conclusion This case highlights the diagnostic challenges associated with atypical pre-excitation patterns and the importance of a thorough evaluation in asymptomatic individuals. Patients with atypical pre-excitation may harbor multiple accessory pathways (MAPs) and should be carefully assessed to mitigate the risk of SCD.