Radiofrequency Lesion Quality Markers: Current State of Knowledge

The long-term efficacy of radiofrequency catheter ablation is highly dependent on the location and size of the lesions delivered via the ablation catheter. This is particularly the case for radiofrequency ablation for atrial fibrillation, where contiguous, transmural lesions are required for durable pulmonary vein isolation. Therefore, reliable lesion quality markers that accurately relate to lesion size in the context of 3D mapping have been sought to improve the reliability of conduction block. Force–time integral, Ablation Index and Lesion Size Index are metrics currently used in clinical practice. Several studies have shown better clinical outcomes using these indices compared with using contact force alone or no marker at all. A theoretical limitation of these composite lesion indices is that they rely on input values such as contact force, application duration and power. A recent technology assessessing local tissue impedance (an output measure) has shown promising results. Temperature, another output measure, is not routinely used due to the significant impact of catheter irrigation on readings, but two recent catheter technologies have sought to overcome this obstacle. This paper provides an update on the current knowledge on these lesion quality markers.