A Completely Non-occlusive Segmental Cryoballoon Ablation for Atrial Fibrillation Guided by High-density Mapping: A Novel Approach and Proof of Concept.

Cryoballoon (CB) ablation traditionally involves obtaining pulmonary vein (PV) occlusion followed by pulmonary vein isolation (PVI). The therapy is guided by time to effect and proximity to the esophagus or phrenic nerve. This, however, requires segmental non-occlusive cryoablation (NOCA) to achieve PVI. While segmental ablation has gained popularity lately with its use during left atrial posterior wall ablation, occlusive PVI remains the mainstay of CB ablation. Many times, this leads to distal lesions and not necessarily wide-area circumferential ablation (WACA) as done with radiofrequency (RF) ablation. In addition, NOCA is guided by estimated balloon positioning as there is no way to see the balloon on the mapping system or to show the exact area of balloon contact as is achievable with contact force catheters. In this case report, we show how a high-density mapping catheter can be used (1) to select the site of ablation on the WACA line; (2) to determine the anticipated location of the CB ablation lesion; (3) to ensure contact; (4) for high-density mapping to ensure PVI; (5) to avoid any PV occlusion and use of related modalities (contrast, left atrial pressure waveform, intracardiac echo, and color Doppler); (6) for short lesions to avoid any change in esophageal temperature of effect on phrenic nerve; and (7) to achieve true WACA similar to as seen with RF ablation in a very predictable manner. We believe that this is the first case report of its kind using a high-density mapping catheter without an attempt made for any PV occlusion.