During RF ablation, which heating mechanism primarily heats tissue immediately beneath the catheter?

• A. Resistive heating
• B. Radiative heating
• C. Convective heating
• D. Conductive heating

Answer: (A)

During RF ablation the energy is delivered right at the catheter tip and the tissue directly under the electrode becomes heated primarily by resistive (Joule) heating. The electrical current encounters tissue resistance and that resistance converts electrical energy into heat right at the interface, making the area immediately beneath the catheter the hottest. As this surface heat builds, the surrounding tissue is warmed mainly by conduction from that hot zone to deeper layers. Radiative heating isn’t a mechanism in RF ablation, and convective heating—heat transfer by moving fluid—plays a much smaller role here compared with the dominant resistive heating at the interface.