Symptomatic premature ventricular contractions in the context of cardiac memory after ablation of a septal accessory pathway in a patient with Wolff-Parkinson-White Syndrome

Wolff-Parkinson-White syndrome (WPW) is a congenital heart condition marked by an accessory pathway (AP) that bypasses the atrioventricular node, which leads to ventricular pre-excitation and often results in paroxysmal supraventricular tachycardia (atrioventricular reentrant tachycardia, AVRT). Catheter ablation of the AP is the preferred treatment for WPW patients with symptomatic AVRT and/or at higher risk of sudden cardiac death due to atrial fibrillation with rapid ventricular response. This report presents a case of symptomatic WPW successfully treated with radiofrequency ablation but followed by transient symptomatic premature ventricular contractions (PVC).
A 27-year-old male with symptomatic WPW was referred to our clinic. The initial ECG (Fig. 1A) confirmed ventricular pre-excitation with a distinct delta wave, indicating a postero-septal or septal AP. An electrophysiological study with open window mapping of the right atrium and ventricle revealed a septal AP and RF ablation was successfully performed from the right atrium. The ECG at discharge (Fig. 1B) showed no signs of pre-excitation but newly emerged negative T-Waves in III and aVF. We interpreted this as cardiac memory, a known phenomenon of persistent T-Wave abnormalities after irregular ventricular activation due to e.g. pre-excitation or ventricular pacing. In the following weeks, the patient presented again due to recurrence of palpitations, particularly during physical exertion. The resting ECG was unremarkable, but holter monitoring and ECG during exercise testing (Fig. 1C) revealed first diagnosis of frequent monomorphic PVCs in correlation to the clinical symptoms. An intermittent atrioventricular conduction via a persisting AP could be excluded by adenosine testing. ECG morphology of the PVC indicated a basal postero-septal origin, thus in proximity to the previously pre-excited region. Low dose Beta-blocker therapy with bisoprolol 1.25 mg twice daily resulted in a notable improvement of symptoms. The beta-blocker therapy was discontinued after a few weeks and no further episodes of palpitations or increased PVC burden were observed. Also, the initial T-Wave abnormalities present in the inferior leads following the ablation were no longer discernible.
This case demonstrates the temporary development of symptomatic PVC after successful ablation of a septal AP in a WPW patient, presumably in the context of cardiac memory after long-standing ventricular pre-excitation. While for a long time, cardiac memory was considered a mere electrocardiographic curiosity it is associated with profound local repolarization dispersion and reduction of repolarizing potassium currents and can even lead to QT-related ventricular arrhythmias, especially in patients with pre-existent QT-prolongation (Viskin et. al., Circulation 2022). Thus, the possible proarrhythmic effects of cardiac memory should be considered in the follow-up of patients after WPW ablation.