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.