THERMAL PROFILES OF PULSED FIELD ABLATION CATHETERS

Pulsed field ablation (PFA) induces cell death predominantly through irreversible electroporation (IRE), a non-thermal mechanism. However, Joule heating during PFA delivery may result in clinically relevant temperature rises.

To characterize the thermal profiles, peak surface temperatures, and ablation lesions produced by six proprietary PFA catheters using an ex vivo vegetal model.

The thermal profile of six PFA catheters - Farawave, PulseSelect, Volt, Varipulse, Electropulse, and Sphere-9 - were evaluated in Solanum Tuberosum at recommended energy settings. Thermal imaging was performed using a high-resolution infrared camera. Standard PFA applications were delivered in five independent runs for each catheter. Post-ablation, specimens were stained with 0.5% triphenyl tetrazolium chloride (TTC) to delineate IRE and reversible electroporation (RE).

All systems demonstrated reproducible and distinct thermal signatures. Mean peak temperature rises were: Varipulse low irrigation flow (4 mL/min), 15.1±1 °C; Farawave basket, 13.6±0.6 °C; Farawave flower, 9.7±0.4 °C; Varipulse high irrigation flow (30 mL/min), 8.5±0.5 °C; PulseSelect, 4.1±0.6 °C; Electropulse, 2.7±0.7 °C; Sphere-9, 2.1±1.2 °C; and Volt, 1.3±0.2 °C (Kruskal-Wallis p<0.0001). PFA catheters demonstrated either localized or distributed thermal hotspot patterns. Localized hotspot catheters confined heating within 1 mm of electrode margin, whereas distributed hotspot catheters exhibited additional peripheral hotspots beyond 5 mm, as observed with Farawave catheter. All catheters produced well-demarcated TTC-unstained IRE lesions surrounded by a rim of TTC-stained RE tissue.

PFA systems exhibit distinct thermal signatures and can be categorized as low (0-6 °C), moderate (6-12 °C), or high (12-18 °C) heating profile catheters.