A novel pulsed field ablation system using linear and spiral ablation catheters can create large and durable endocardial and epicardial ventricular lesions in vivo.

Background: We investigated the preclinical safety and efficacy of ventricular pulsed field ablation (PFA) using a family of novel, 6-/8-Fr, linear, and spiral PFA/mapping catheters (CRC EP, Inc).

Methods: QRS-gated, bipolar PFA (>2.0 kV) was performed in 10 healthy swine. Altogether, 20 endocardial and epicardial right and left ventricular applications were delivered. The catheters were inserted through an 8.5-Fr steerable introducer. The intensity of skeletal muscle activation was quantified using an accelerometer. Lesions were assessed by pre- versus post-PFA electrogram analysis, pacing threshold, 3D voltage mapping, necropsy, and histology. The swine rete mirabile, liver and kidneys were examined for embolic events.

Results: All applications were single-shot (56 ± 18 s) without catheter repositioning. Minimal microbubbling was observed without significant skeletal muscle stimulation (mean acceleration 0.05 m/s) or ventricular tachyarrhythmias. There was significant reduction in post- versus pre-PFA electrogram amplitude (0.5 ± 0.2 mV versus 3.2 ± 0.9 mV, P < 0.001) with a marked increase in pacing threshold (>20 mA versus 7.5 ± 2.9 mA, P < 0.001). All lesions were large and durable up to 28 days, measuring 32 ± 5 mm (length), 27 ± 8 mm (width), and 8 ± 3 mm (depth) using the spiral catheters and 43 ± 1 mm (length), 7 ± 1 mm (width), and 8 ± 1 mm (depth) using the linear catheters. Despite higher waveform voltages and prolonged applications, no thermal effects were detected at necropsy/histology. Moreover, gross and microscopic examinations revealed no evidence of thromboembolism, vascular or collateral injury.

Conclusions: A novel, QRS-gated PFA system using linear and spiral PFA catheters is capable of creating large and durable ventricular lesions in vivo without significant microbubbling, ventricular arrhythmias or thromboembolism.