The Importance of Electrode-Tissue Proximity in Creating Durable Pulsed
Field Ablation Lesions: Insights From a Preclinical Model
Background: We sought to evaluate the anatomic and functional
lesion development over time at different atrial sites immediately
following delivery of pulsed field ablation (PFA). Methods:
Using a porcine model, PFA ablations were performed in the superior vena
cava (SVC), right atrial lateral wall (RA), left atrial appendage (LAA)
and right superior pulmonary vein using four different PFA profiles.
Mapping was done sequentially in 5–20-minute increments up to
280-minutes post lesion delivery for low voltage area (LVA) assessment
and conduction velocity. Lesion characteristics were noted with voltage
mapping immediately post ablation and at the serial time points.
Results: In 9 animals, 33 sites were ablated. None of the four
different profiles across all sites any statistical difference on acute
lesion formation or persistence. Higher tissue contact was observed in
the SVC and RSPV and lower tissue contact was observed in the LAA and RA
locations. Higher contact areas were noted to have higher density
electroanatomic low voltage area (LVA) (12/14 vs 5/18, p=0.01) and
larger lesions on gross pathology (2 /14 vs 6/16, p =0.01) compared to
lower contact areas. Lesion regression occurred in 16/33 sites.
Sustained lesions were significantly more prevalent in higher versus
lower contact sites (65% vs 38%, p=0.037). Conclusion: The
development of significant and durable lesions for PFA appears to be
dependent on tissue proximity and contact.