Radiofrequency lesion formation prediction with contact force versus local impedance

Purpose of review Safe and effective radiofrequency (RF) myocardial ablation requires real-time monitoring of lesion formation. Here, we review conventional and novel approaches proposed to guide titration of RF energy application. Recent findings Conventional monitoring modalities, such as ablation electrode temperature, generator impedance, and tissue electrophysiological properties have been of limited value in predicting efficacy and safety of ablation. Therefore, several input-driven indices have been proposed to improve the quality and durability of RF ablation lesion while maintaining safety. These metrics predominantly incorporate RF power output, duration of RF application, and firmness and stability of electrode-tissue contact. More recently, novel catheters have enabled measuring local impedance at the catheter-tissue interface, which has been found valuable for real-time monitoring of RF lesion formation. Summary It is likely that using the combination of multiple metrics would be required to improve the quality and safety of RF lesions, but further investigation is still required.