Catheter ablation of para-hisian premature ventricular contractions using electroanatomical mapping: Approaches and pitfalls.

A 58-year-old female patient presented at cardiology outpatient clinic with palpitation. The 12-lead electrocardiography on admission revealed monomorphic bigeminy premature ventricular contractions (PVCs) showed a left bundle-branch block configuration, monophasic R wave in lead I and aVL and precordial transition in V3 lead. Cardiac electrophysiological study was performed to patient. Activation mapping guided by three-dimensional electroanatomic system was done. The earliest ventricular activation was observed in the para-hisian region with the largest His potential (0.6 mV) during PVC. Due to the risk of atrioventricular (AV) block, radiofrequency (RF) ablation was planned to the region, where the His potential amplitude was lower (0.2 mV), the AV ratio was <1, and ventricular activation preceded the QRS onset by 37 ms. Subsequently, irrigated RF current was delivered in the distal His region with power starting at 15 W after PVC was suppressed, RF delivery was applied for a total of 90 s with gradually increasing power to 25 W. After ablation, under isoproterenol infusion, burst pacing from the right ventricle no PVCs/VTs was observed. A gradual RF energy application, a detailed activation mapping, and the distance from the largest His potential increase the likelihood of success in para-hisian PVC ablation.