Supplementary figure 3.

A: High-resolution open window mapping during RV pacing with sharp, isolated AP potentials at the lateral mitral anulus along the adjacent H spline micro-electrodes with close 2-mm spacing. B: The first RF delivery targeting the earliest, isolated AP potential (unipolar OctaR H4) led to instant loss of pre-excitation along with instant AP automaticity (asterisks) with eccentric CS activation similar to retrograde AP conduction during RV pacing.