Case 1
A 71-year-old man underwent an ablation procedure for PVCs at 35,000 beats/day. The PVCs had a right bundle branch block/inferior axis configuration (Figure 1A). An “M”-shaped discrete presystolic-potential preceding the QRS onset of the PVC by 32 ms was seen at the right coronary cusp-left coronary cusp commissure, where a “W”-shaped discrete late-potential was recorded during SR (Figure 1B). The configuration of the flipped electrogram of the presystolic-potential nearly matched that of the electrogram exhibiting the late-potential during SR. We created coherent activation maps annotating the onset of the presystolic potentials during the PVC (PVC map, Figure 1C) and offset of the late potentials during SR (SR map, Figure 1D). Those potentials and vector map revealed the bidirectional conduction of the preferential pathway connecting the PVC origin in the right coronary cusp-left coronary cusp (LCC) commissure to the LVOT myocardium. An RF application (30 W) at that site eliminated both the PVCs and late potential during SR within 4.5 seconds.