Figure 5. Representative images of the dedicated RF wire system, electrified guidewires (EG) and respective dilators using an optical microscope (A) before transseptal puncture and (B) after transseptal puncture. The dedicated RF wire system showed no damage. In both 0.014” and 0.032” EG setups, the metal wire tip was melted and/or deformed, and the respective dilator showed signs of melting and charring. Images show representative devices at moderate power levels and 1mm distance between the dilator tip and wire tip, corresponding to the highest EG transseptal puncture effectiveness. (Scale bar is 1mm.)