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. 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. 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. 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. 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. 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.