Introduction: Pulmonary vein isolation (PVI) is well established as the preferred treatment for symptomatic paroxsysmal atrial fibrillation (pAF). We introduce a novel technique in which PVI is aimed for in a pig model, by non invasive heating of the proximal ring of an implant inserted in the pulmonary veins.
Hypothesis: Non-invasive heating of an implant in the PV is feasible and safe
Methods: A self-expanding nitinol-based implant was positioned in the common inferior pulmonary vein of 11 pigs, using a fluoroscopy guided transatrial approach. In a second part of the experiment, implants were positioned in the superior caval vein through a transfemoral approach of another 6 animals. Ablation was performed through a contactless energytransfer from a primary extracorporal coil to a secondary heatring (HR) embedded in the proximal part of the implant. Electrophysiological properties were assessed prior to and post ablation. Histological samples were obtained after 3 months.
Results: In total, eightteen PV-implants were succesfully positioned. Ablation was performed in a safe manner, without injury of adjacent structures. PVI and bidirectional block was confirmed in all PV cases, and bidirectional block in 5 of the 6 caval vein implants (entry block shown in the figure-the heatring is at the level of the white arrow). Only mild neointimal proliferation was observed 3 months post ablation.
Conclusions: Non-invasive ablation using self-expanding stents in the PV is safe and feasible, bidirectional isolation can be demonstrated in almost all cases, whilst no significant neointimal formation is observed: