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.