A 76-year-old man presented with frequent premature ventricular contractions (PVCs). The electrophysiological findings revealed the origin of the PVCs was in the posterior-superior process of the left ventricle (PSP-LV), which is anatomically adjacent to the infero-medial aspect of the right atrium (RA). After a failed ablation from the LV, ablation in the RA eliminated the PVCs. During additional ablation, the atrio-his (AH) interval was monitored by atrial overdrive pacing, and ablation was terminated immediately after the AH interval prolonged to 174 ms. We believe that the atrial overdrive pacing was useful for monitoring the AH interval to prevent atrioventricular block during ablation of PVCs from the PSP-LV. <Learning objective: PVCs from posterior-superior process of the LV (PSP-LV) could be eliminated by radiofrequency ablation at the posterior-septum of the RA. It is important to closely examine the AH interval in order to prevent any atrioventricular block during the ablation of PVCs originating from the PSP-LV. Atrial overdrive pacing is helpful to monitor the AH interval during the ablation of PVCs originating from the PSP-LV.>.
Keywords: Atrio-his interval; Atrioventricular conduction system; Catheter ablation; Posterior-superior process of the left ventricle; Ventricular premature contraction.