Electrothermal multiphysics coupling mechanisms and experimental study on the effect of left atrial appendage occluders on the efficacy of pulsed field ablation

Background Pulsed field ablation (PFA) is a novel non-thermal technique, but its effect on tissues with left atrial appendage occluders (LAAOs) has not been fully and effectively evaluated. Objective: This comprehensive study systematically analyzes the influence of LAAOs on ablation zones and temperature rise via multiphysics coupled computational simulations and ex vivo tissue experiments. Methods A simplified target model was developed. Lesion extent was assessed using the 400 V/cm isoelectric contour, while temperature changes in the ablation zone were recorded simultaneously. Animal myocardial tissue was used for validation purposes. Results Electrode configuration significantly affected ablation outcomes. Configuration 2 exacerbated electric field distortion, causing incomplete lesion formation. The maximum temperature difference across configurations was 2.61°C, with a peak of 45.45°C. The spatial relationship between electrode and LAAO also quantitatively influenced the ablation zone. Ex vivo experiments showed negligible field distortion, uniform lesion width and depth, and progressive temperature rise with pulse parameters. Conclusion LAAO minimally impacts the target zone. Different electrode configurations adjust the ablation range without causing thermal injury. Ex vivo data confirmed the temperature rise effect. This study offers important clinical guidance for circular catheter PFA treatment in atrial fibrillation patients with an LAAO.