Catheter ablation of right-sided para-Hisian ventricular arrhythmias using a simple pacing strategy

Background: Ablation of para-Hisian ventricular arrhythmias (PH-VAs) is challenging because of the close relationship of the origin site and His bundle. Using pacing techniques to differentiate the near-field from far-field His activations, thereby avoiding atrioventricular block, has been reported in patients with para-Hisian accessory pathways.

Objectives: We applied the same pacing technique and 3-dimensional mapping to guide radiofrequency (RF) ablation in patients with right-sided PH-VAs and investigated the clinical outcome of such cases.

Methods: Fourteen patients with right-sided PH-VAs were included in this study. The earliest activation sites were confirmed in the right ventricle on the 3-dimensional map. Pacing with different outputs was performed at the largest His potential site (P1) and the earliest activation site (P2). If the minimum His bundle-right bundle branch-captured output at P2 was higher than that at P1, RF ablation was performed at the site.

Results: All the patients in this study had monomorphic premature ventricular contractions (PVCs) with a mean QRS duration of 118.3 ± 8.1 ms. A His-right bundle branch potential with an amplitude of 0.05 ± 0.02 mV was recorded at P2, with a mean distance of 5.97 ± 1.84 mm away from P1. PVCs were successfully eliminated in 13 of 14 patients (92.9%). One patient exhibited persistent right bundle branch block after ablation, and 1 recurrence of ablated PVCs occurred during a median follow-up period of 15 months.

Conclusion: Using a simple pacing technique to evaluate the safety of RF energy application led to a high success rate of RF catheter ablation of right-sided PH-VAs without atrioventricular block.