Preclinical evaluation of a novel 8-spline pulsed field ablation system

Pulsed field ablation (PFA) technologies offer the potential for improved procedural efficacy and safety. Circumferential pulmonary vein (PV) ablation approaches are attractive compared with point-by-point, simplifying workflow.

We evaluated the safety and efficacy of a novel, over-the-wire, balloon-based basket-shaped catheter achieving rapid, durable PV isolation (PVI) with a simple workflow.

PFA was delivered to the right superior, right inferior, left superior, and left inferior PVs in 18 male canines (25-45 kg). There were 3 groups of 6 animals that survived for 34 ± 4 days. Group 1 (low voltage, 3 applications) also included a safety challenge in which PFA was applied in the superior vena cava directly adjacent to the phrenic nerve. Group 2 (nominal voltage, 8 applications) represents the maximum recommended dose, completed with the esophagus deviated to the left atrial posterior wall and used for PV stenosis assessment. Group 3 (nominal voltage, treated until PVI, 2-8 applications) represents the standard settings for ablating the PVs in a clinical workflow.

All animals survived, showed no significant PV stenosis nor esophageal injury, and retained phrenic nerve pace capture ≥30 minutes after PFA and 30 days. At 30 days, 90.9% (n = 20 of 22) in group 1, 100% (n = 23 of 23) in group 2, 95.2% (n = 20 of 21) in group 3, and 95.5% (n = 63 of 66) overall demonstrated bidirectional PV block. Histopathologic assessment revealed transmural fibrotic lesions with evidence of "vessel sparing," but absence of tissue necrosis and thrombus. The esophagi and main coronary arteries were grossly and microscopically normal with no evidence of coronary artery stenosis. Other collateral tissue damage and embolic lesions were minimal and clinically insignificant.

This novel PFA system demonstrated effective and durable chronic PVI over a range of PFA amplitudes and applications with favorable usability and an optimal safety profile.