Thermal behavior during pulsed field ablation with the pentaspline catheter: An in vivo and in vitro evaluation

Although pulsed field ablation (PFA) is typically a non-thermal ablation modality, temperature elevations have been reported, potentially causing thermal tissue damage. Their occurrence and relationship to pentaspline catheter pose is not well-characterized.

To determine the relationship between catheter configuration, temperature rises, electrical arcing, microbubble formation, and generator errors during pentaspline PFA.

Temperatures were evaluated in vitro, using explanted swine atrial tissue positioned over a multi-sensor temperature probe immersed in half-normal salinev, and in vivo with an epicardial probe opposite the endocardial catheter. Pentaspline PFA was delivered in small basket and olive configurations of varying diameters. Temperature rises, visible arcing, microbubble formation, and the occurrence of generator errors were recorded.

In vitro, a total of 40 applications were analyzed. Temperature rise was inversely associated with catheter diameter (P < .001), with greater increases in <14-mm poses than ≥18-mm poses (3.15°C vs 2.27°C; P = .008). Arcing occurred in 30% of applications and was associated with smaller catheter diameters (P < .001) and greater temperature rises (3.29°C vs 2.47°C; P < .001). In vivo, 50 of 68 attempted deliveries were successfully completed. Greater temperature rises were noted with smaller basket poses (P = .016), with higher elevations in <14-mm compared to the 14-18-mm diameter poses (1.95°C vs 1.31°C; P = .023). Severe microbubbles occurred only in smaller configurations. Generator errors occurred in 18 of 68 deliveries, and more frequently with smaller poses.

Modest temperature rises below the thermal injury thresholds may occur during pentaspline applications. Smaller basket poses are associated with greater temperature rises, arcing, microbubbles, and generator errors.