Thermal side effects during pulsed field ablation: an analysis using computer modelling

AIMS: Pulsed field ablation (PFA) is described as non-thermal, but data from oncology and cardiology show thermal effects occur. The specific waveform parameters influencing thermal energy development during PFA are unclear. The aim of this study is to numerically evaluate the thermal effects of PFA on myocardial and oesophageal tissue at various peak voltage conditions. METHODS AND RESULTS: A three-dimensional computer model of the left atrium quantified thermal effects from PFA at peak voltages of 1, 1.5, and 2 kV. Energy was applied using a bipolar configuration with far-field and symmetry boundaries set as electrically insulating. A monophasic waveform with a 100 μs pulse width and a 1 s gap between pulses was applied for a total of 50 pulses, mimicking clinical conditions. Minimal temperature rise in the oesophagus was observed with 1 kV pulses (214.5 J). At 1.5 and 2 kV (570.3 and 1.23 kJ), temperatures reached 46.3°C and >62°C, respectively, after a single pulse train. These findings suggest that repeated applications could lead to even higher temperatures, especially if good tissue contact is obtained. These results align with data from other medical fields using pulsed field treatments. CONCLUSION: Thermal effects from PFA depend on the total energy deposited, with peak voltage being a significant factor. Current commercially available PFA systems have the potential to induce collateral thermal injury with repeated applications of pulsed field energy. This highlights the need for careful monitoring and adjustment of PFA parameters in clinical settings.