Keywords 
Radiofrequency ablation, lesion formation, contact force, insulated-tip
catheter
Radiofrequency (RF) ablation was initially proposed by Huang et al. in
1985 and has been the most widely employed energy source for catheter
ablation to date (1-2). RF ablation transfers electromagnetic energy
into thermal energy by a process called resistive heating at the surface
of tissue (3). Meanwhile, the efficiency of RF energy application is
highly affected by multiple factors, including power, duration,
electrode contact area, and contact force. Catheters have continuously
evolved over the past decades with the goal of delivering RF energy with
greater safety and efficiency. The ideal catheter would create
reproducible, reliable lesions while eliminating the risk of steam pops,
perforation, or collateral damage to surrounding tissue. A major
advancement has been the development of irrigated and contact force
sensing catheters, which has improved the safety and efficiency, and
perhaps the effectiveness of catheter ablation procedures. (4). Even
with good contact using high-power setting, most of conventional RF
ablation energy dissipates into the bloodstream before reaching the
target tissue, which is called convective cooling (5). Convective
cooling is the major thermodynamic factor opposing the transfer of
thermal energy to deeper tissue layers. In response to these opposing
forces, higher power and longer duration of RF energy is often applied.
However, it also increases the risk of unfavorable complications, steam
pop and coagulum. Technology that conveys RF energy exclusively toward
target tissue may potentially improve the quality, safety, and outcome
of the RF ablation procedures.