What characterizes the type of lesions formed during unipolar RF?

During unipolar radiofrequency (RF) ablation, the resulting lesions are characterized as narrow and deep. This is primarily due to the focused nature of the energy delivery in unipolar systems, which concentrates the RF energy toward a specific tissue area. The design and operation of unipolar RF devices typically lead to greater penetration of the current into the tissue, yielding deeper lesions compared to other modalities. The depth and narrowness of these lesions can be advantageous in targeting specific structures, such as certain types of tumors or arrhythmic foci, without causing widespread damage to surrounding healthy tissue.

This characteristic of narrowness allows for precise treatment, which is crucial in delicate anatomical regions. In contrast to this, lesions that are wide and shallow, irregular and superficial, or uniform and superficial do not accurately reflect the physiological and electrical dynamics at play with unipolar RF ablation, as these describe characteristics that would be more associated with different ablation techniques or thermal energy applications.