Abstract 9835: Multi-Modality Imaging Assessment of Microbubbles and Cerebral Emboli in Left Ventricular Pulsed Field Ablation

Abstract

Introduction: Pulsed field ablation (PFA) may have a superior safety profile compared to other ablation technologies, but the high-voltage electrical fields have the potential to cause gaseous microbubbles (MB), which may be associated with cerebral emboli. In this study, we evaluate the MB burden of a monopolar, biphasic PFA system (CENTAURI, Galaxy Medical), that delivers a waveform designed to limit MB generation. Methods: After anticoagulation with heparin, healthy and chronic MI swine (30 day survival after 90 minute coronary balloon occlusion) underwent PFA in the LV using an open-irrigated focal catheter under intra-cardiac echocardiography (ICE) guidance and monitoring of MBs. Two additional healthy control swine received 0.5 and 1 ml of air MBs through the lumen of the ablation catheter. Swine underwent brain MRI before and after PFA (or control air MB injection) with T1, T2, FLAIR, ADC and susceptibility- and diffusion-weighted imaging (DWI) interpreted by a neuroradiologist blinded to treatment group. Gross pathology and histology of brains with any MRI findings was performed by a neuropathologist. Results: Four healthy swine underwent 50 PFA applications and 5 chronic MI swine underwent 74 applications. No PFA-related MB formation was noted on ICE. Both control swine developed multiple acute emboli in the left thalamus and caudate on DWI, ADC and FLAIR brain MRI sequences in response to air MB injection (Figure). Of the 9 PFA swine, there were no ADC nor FLAIR sequence abnormalities. There was one instance of a hyperintense focus in the left putamen on the DWI trace image, but absence of ADC or FLAIR affirmation suggested it was artifact. Gross pathology and histopathology of this region did not detect any abnormalities (Figure). Conclusion: Catheter air MB injection caused MR-detectable cerebral emboli in swine. Focal monopolar biphasic PFA with CENTAURI does not generate MBs observable on ICE, and did not cause cerebral emboli in healthy or post-infarct LVs.