Where is the highest tissue temperature located during RF ablation?

During radiofrequency (RF) ablation, the highest tissue temperature is typically found slightly below the endocardial surface. This occurs because RF energy is delivered through the catheter tip, and while the tip heats up and transfers energy to the surrounding tissue, the peak temperature is not at the tip itself but rather where the energy is focused into the tissue. The energy disperses as it penetrates into the cardiac tissue, and the highest temperature achieved is usually in the deeper layers just beneath the endocardium, where the tissue is most affected and where the temperature rises to levels sufficient for creating the desired therapeutic effect, such as inducing lesions.

In contrast, the surface of the skin does not experience the same temperatures due to the protective and insulating properties of the dermal layers, which dissipate heat. Blood flow also acts as a cooling mechanism; therefore, areas with significant blood flow will not achieve the high temperatures necessary for effective ablation. Instead, it is the targeted tissue beneath the endocardium that experiences the most significant thermal effects during the procedure.