Combined pulsed field ablation with ultra-low temperature cryoablation: A preclinical experience |
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| Authors: | Atul Verma MD FRCPC Gregory K Feld MD James L Cox MD Thomas A Dewland MD Alexei Babkin PhD Tom De Potter MD Narayan Raju DVM PhD Michel Haissaguerre MD |
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| Institution: | 1. McGill University Health Centre, 2. Division of Cardiology, Montreal, Quebec, Canada;3. Division of Cardiology, University of California San Diego, La Jolla, California, USA;4. Division of Cardiac Surgery, Northwestern University, Chicago, Illinois, USA;5. Division of Cardiology, University of California San Francisco, San Francisco, California, USA;6. Adagio Medical, Laguna Hills, California, USA;7. Division of Cardiology, Cardiovascular Center, OLV Aalst, Aalst, Belgium;8. Pathology Research Laboratory, San Francisco, California, USA;9. Division of Cardiology, Centre Hospitalier Universitaire Bordeaux, Pessac, France |
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| Abstract: | Background Combining pulsed field ablation (PFA) with ultra-low temperature cryoablation (ULTC) represents a novel energy source which may create more transmural cardiac lesions. We sought to assess the feasibility of lesions created by combined cryoablation and pulsed field ablation (PFCA) versus PFA alone. Methods Ablations were performed using a custom PFA generator, ULTC console, and an ablation catheter with insertable stylets. PFA was delivered in a biphasic, bipolar train. PFCA precooled the tissue for 30 s followed by a concurrent PFA train. Benchtop testing using Schlieren imaging and microbubble volume assessment were used to compare PFA and PFCA. PFA and PFCA lesions using pre-optimized and optimized ablation protocols were studied in 6 swine. Pre and post-ECGs were recorded for each ablation and a gross necropsy was performed at 14 days. Results Consistent with benchtop comparisons of heat and microbubble generation, PFA deliveries in the animals were accompanied by muscle contractions and significant microbubbles (Grade 2–3) visible on intracardiac echo while neither occurred during PFCA at higher voltage levels. Both PFA and PFCA acutely eliminated or highly attenuated (>80%) local atrial electrograms. Histology of PFA and PFCA lesions indicated depth up to 6–7 mm and nearly all lesions were transmural. Optimized PFCA produced wider cavotricuspid isthmus lesions with evidence of tissue selectivity. Conclusion A novel technology combining PFA and ULTC into one energy source demonstrated in-vivo feasibility for PFCA ablation. PFCA had a more favorable thermal profile and did not produce muscle contraction or microbubbles while extending lesion depth beyond cryoablation. |
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| Keywords: | animal combination cryoablation preclinical pulsed field ablation |
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