Thermal profiles for focal pulsed electric field ablation

Abstract

Background. Pulsed electrical field (PEF) ablation may cause tissue heating. These changes are reportedly small, but each PEF system and waveform will have a different behavior, and data are lacking. Objectives. This study sought to compare the temperature profile of focal point, monopolar biphasic PEF ablation versus radiofrequency (RF). Methods. Ablation lesions were performed on perfused thigh muscle of swine. PEF lesions were performed with 3 compatible ablation catheters at the highest (25 amp) energy, and 1 catheter (Tacticath SE) was also used at the 22- and 19-amp levels. Temperature changes in the tissue were measured using fluoroptic temperature probes inserted at the muscle surface, as well as 3 mm and 7 mm below the surface. Temperatures were recorded continuously at baseline, during delivery, and after ablation. Muscle temperatures were compared with those of RF lesions performed with 1 catheter (Tacticath SE) at 30 W for 30 seconds. Results. PEF ablation with 3energy settings produced small temperature changes. Maximum average temperature rise for PEF for the maximum (25-amp) energy setting (32 lesions) was 7.6 °C, 2.8 °C, and 0.9 °C at the surface, 3-mm depth, and 7-mm depth, respectively. The temperature rise was dose dependent, with lower energy settings yielding less temperature rise. RF ablations (10 lesions) produced temperature increases of 16.6 °C, 39.8 °C, and 9.5 °C at the surface, 3-mm depth, and 7-mm depth, respectively. Conclusions. PEF caused detectable temperature changes in muscle tissue, which never exceeded 2.8 °C at the 3-mm depth versus baseline. By contrast, RF produced substantial temperature rises. These data support that focal monopolar biphasic energy delivered by this PEF technology retains a favorable thermal safety profile.