Quantification of thermal side effects during pulsed field ablation

Background and AimsPulsed field ablation (PFA) has been described as non-thermal, but abundant data exist in oncology applications, and growing data are emerging in cardiology, highlighting that thermal effects are in fact present with PFA. Our objective was to develop a reliable model of the thermal effects arising from PFA of myocardial and esophageal tissue over a range of typical peak voltage operating conditions. MethodsWe developed a three-dimensional computer model of the left atrium that can quantify the thermal effects from PFA applications. Energy was applied using a bipolar configuration, and far-field and symmetry boundaries were set as electrically insulating. The model utilizes a monophasic waveform with a pulse width of 100 s and gap between pulses of 1 s was applied for a total of 50 pulses in a single train, with variations to this easily implemented to accommodate various conditions. ResultsOver a range of peak voltage operating conditions (1 kV, 1.5 kV, and 2 kV), minimal temperature rise in the esophagus was seen with 1 kV pulses (corresponding to 215 J input), but with 1.5 kV and 2 kV peak voltages (corresponding to 570 J and 1.23 kJ), temperature elevations reaching 46.3{degrees}C and > 62 {degrees}C were seen, respectively. These elevations occurred after only a single pulse train of 50 pulses, implying that further elevations in temperature would be seen with subsequent applications. These findings concur with data published in other fields of medicine where pulsed field treatments are utilized. ConclusionsThermal effects from PFA occur and can be quantified with in-silico modeling. The model described here offers an efficient means of determining temperature effects from PFA over various operating conditions. Energy levels used clinically appear to have the potential to induce collateral thermal injury with repeated applications of pulsed field energy.