Impact of catheter type on lesion dimensions in focal-bipolar pulsed field ablation

Pulsed field ablation (PFA) is a novel technique for pulmonary vein isolation (PVI) in the treatment of atrial fibrillation (AF). However, the impact of electrode type on lesion formation at fixed PFA parameters remains unknown. This study investigated differences in lesion characteristics when using a 4 mm non-irrigated catheter versus an open-irrigated flexible-tip catheter in focal-bipolar PFA in a vegetable model.

PFA applications were performed in a potato model using a purpose-made PFA generator, applying both a solid-tip 4 mm non-irrigated catheter and an open-irrigated flexible-tip catheter under identical energy delivery parameters. After electroporation, potatoes were stained with triphenyltetrazolium chloride (TTC) to visualize lesion boundaries. Depth, diameter, and volume of the irreversibly electroporated zones were measured to assess the impact of each electrode type.

A total of fifty PFA applications were performed—25 with the 4 mm non-irrigated catheter and 25 with the open-irrigated flexible-tip catheter. The depth of the irreversible electroporation zone was significantly greater with the 4 mm non-irrigated catheter than with the irrigated electrode (1.7±0.5 mm vs. 1.4±0.7 mm, p=0.03). The diameter of irreversible lesions created with the 4 mm electrode was 7±1 mm, compared to 6±1 mm with the irrigated electrode (p=0.001), resulting in a total lesion volume of 185 mm³ versus 120 mm³, respectively (p=0.0008).

The use of a solid-tip 4 mm non-irrigated catheter in focal-bipolar PFA create lesions with greater depth, volume and diameter compared to an open-irrigated flexible-tip catheter. Ablation catheter type significantly influences lesion spread during focal-bipolar PFA.