Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Ablation Techniques D-AB07 - Alternate Techniques in Energy Sources (ID 6) Abstract Plus

D-AB07-04 - Preclinical Assessment Of Feasibility And Durability Of Mitral Isthmus Ablation Using Pulsed Field Ablation (ID 745)


Background: RF catheter ablation to achieve a durable mitral isthmus (MI) line is frustrated by the heat sink effect of the epicardially-situated coronary sinus (CS). Because of its non-thermal ablative mechanism, pulsed field ablation (PFA) may be uniquely capable of achieving transmural MI lesions - even atop the CS.
Objective: To assess the feasibility and durability of PFA ablation of the MI using a 9mm lattice-tip ablation catheter (Sphere-9, Affera).
Methods: Under general anesthesia, the lattice-tip catheter with the compatible electroanatomical mapping system (Sphere-9 and Prism-1, respectively; Affera Inc) and ICE imaging (Acunav, Siemens Inc) were used to create a MI line in 6 swine. Baseline and chronic voltage maps were created. All swine were sacrificed at 12.2±1.2 days, and tissue submitted for pathology.
Results: A mean of 6.8±0.8 applications were required to complete the MI line, with an ablation time of 44.3±7.7 sec without complications. Linear low voltage regions were noted in all 6 of 6 (100%) swine at follow up. The mean width of the mitral isthmus lesions based on bipolar voltage (0.1-0.5mV) was 16.4±6.0 mm. On gross necropsy, the MI lesions were easily detectable on the endocardium in 4 of 6 swine despite the faint appearance characteristic of PFA lesions. The CS was opened in 5 of 6 swine to appreciate lesion transmurality: the PFA lesions were detected on the roof of the CS in all 5 of 5 swine.
Conclusion: Point-by-point PFA using the lattice-tip catheter can create transmural lesions along the mitral isthmus with ablation delivery times of <1 min. The insensitivity to convective cooling by the CS blood flow may explain the ease with which PFA make these transmural lesions.