Po-04-063 effect of pulsed field ablation on the bronchus: preclinical insights

The relative tissue selectivity of pulsed field ablation (PFA) allows for the safe delivery of ablation lesions even when in close proximity to collateral tissues such as the esophagus and phrenic nerve. Frequent coughing spells during PFA of the left atrium can be frequently seen during clinical procedures; there is little insight into the mechanism and effects on the bronchi. To assess the effect of PFA on the bronchus in swine. Microsecond pulses were delivered in a single swine under general anesthesia with fluoroscopic guidance. A standard ablation catheter (Blazer II, Boston Scientific, 7Fr and 4mm tip) and a commercially available microsecond pulse generator (ECM 830, BTX) were used. Bipolar, biphasic mode of microsecond pulse delivery (750kV) was applied with 5 repetitions of ∼1 second-long applications within the bronchus. Tetrazolium chloride staining was performed and the swine was humanely sacrificed after 2 days. Histological assessment was performed after formalin fixation with Hematoxylin and Eosin staining. A total of 7 PFA lesions were created in both the right and left bronchi. Only 2 of 7 lesions were identified at necropsy (Figure). The lesions were oval in shape and pink-white in the center surrounded by a zone of hyperemia. Histology demonstrated disappearance of cilia and mucosal cells at the site of the PFA lesions compared to the adjacent normal tissue. The layer of respiratory epithelium was denuded. Structures beneath the epithelium, including lamina propria, smooth muscles, mucosa glands, and cartilage were spared without evidence of any hemorrhage or inflammation. This exploratory sampling of bronchial susceptibility to PFA suggests minimal damage to the epithelium. Detailed post-PFA bronchoscopy studies would be necessary required to assess if such lesions are seen during left atrial ablation procedures.