Abstract 3880: Novel Development of Cryoballoon Ablation of LV Myocardium: A Potential Solution for Outflow Tract and Apical Hypertrophy
Background: Cryoballoon technology is currently successfully applied for ablation of atrial fibrillation (AF) with few complications. We extended the range of this intervention by testing the feasibility of ablating LV apical and outflow tract tissue using a redesigned cryoballoon capable of high refrigerant flow rates.
Methods: Four mongrel dogs underwent ablation of LV endocardial surface. The cryoballoon was positioned deep in the apex or at the base of the LV where cryothermal energy was delivered for 4 minutes. Post-necropsy ablative lesions were measured for size, transmurality, and predictive capability for reducing apical or outflow tract hypertrophy.
Results: Successful ablation of the LV was achieved in all animals using a side-on approach. Each LV chamber underwent a single 4 minute ablation with cryothermal energy delivery achieving minimum temperatures of −66±5.3 degrees C. Mean lesion size was 17.8±2.3 by 24.5±6.3 mm. Mean lesion depth was 9.8±5.4 mm. Transmural ablations were noted in 3 of 4 animals. In either location, lesions were very extensive without destabilized ventricular function.
Conclusion: Large ablations using a side- or end-on approach with high cryoballoon refrigerant flow successfully creates deep subendocardial and full thickness LV lesions. The feasibility shown in these studies predicts a useful role for cryoballoon technologies in the successful ablation of hypertrophic cardiomyopathy.