Determination of Continuity Index Values in Atrial Fibrillation Ablation with Proactive Esophageal Cooling

This protocol describes the methods used to determine the continuity index in patients undergoing pulmonary vein isolation procedures using radio frequency ablation, and demonstrates the differences in continuity index between ablation procedures using proactive esophageal cooling, as compared to procedures using luminal esophageal temperature monitoring. Proactive esophageal cooling using a dedicated device has been granted marketing authorization by the Food and Drug Administration to reduce the likelihood of ablation-related esophageal injury, resulting from radio frequency ablation procedures, and long-term follow-up data suggests improved freedom from arrhythmia when using cooling, as opposed to LET monitoring. Ablation and mapping catheters provide a variety of lesion quality markers, including impedance decline, catheter tissue contact force, catheter stability, and bipolar electrogram amplitude reduction, which serve as evidence of transmural contributing to PVI effectiveness.

However, continuity index is not a marker provided by current devices and technologies, and currently requires manual assessment. Proactive esophageal cooling allows for a contiguous placement of sequential lesions without interruption or the need to pause for local overheating or temperature alarms. This, in turn, decreases operator cognitive load and procedure time, and allows for increased lesion continuity, or low continuity index, potentially increasing long-term PVI success.

Low continuity index as a result of cooling may not only increase the durability of lesions, resulting in a higher freedom from arrhythmia, but also minimizes risks of thermal injury to critical structures that remains when using reactive luminal esophageal temperature monitoring, and eliminates the need for deviation of critical structures.