The utility of atrial overdrive pacing during catheter ablation of premature ventricular contractions originating from the posterior-superior process of the left ventricle.

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 174ms. 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.