Electrophysiological responses of the left atrial appendage during pulsed-field electrical isolation utilizing a novel device in a canine model.

BACKGROUND: The electrophysiological responses of the left atrial appendage (LAA) during pulsed-field electrical isolation have not been established. OBJECTIVE: This study aims to investigate the electrical responses of the LAA during pulsed-field electrical isolation using a novel device and their relations to acute isolation success. METHODS: Six canines were enrolled. The E-SeaLA™ device, which is able to perform LAA occlusion and ablation simultaneously, was deployed into the LAA ostium. LAA potentials (LAAp) were mapped via a mapping catheter, and the LAAp recovery time (LAAp RT, the time between the last pulsed spike and the first recovered LAAp) was measured after pulsed-train delivery. The initial pulse index (PI, corelated to pulsed-field intensity) was adjusted during the ablation procedure until LAAEI was achieved. Acute LAA electrical isolation (LAAEI) success was defined as LAAp disappearance or exit and entrance conduction block, confirmed through a drug test and a 60-minute waiting period. RESULT: All canines achieved successful LAA occlusion without peri-device leaks. Acute LAA electrical isolation (LAAEI) was achieved in five out of six canines (5/6, 83.3%). Very late LAAp recurrence (LAAp RT > 600 s) was observed during PFA. Early recurrence (LAAp RT < 30 s) was observed in two canines (2/6, 33.3%) post-PFA. Intermediate recurrence (LAAp RT ~ 120 s) was observed in three canines (3/6, 50%) post-PFA. The two canines with intermediate recurrence achieved LAAEI with higher PI ablations. The one canine with early LAAp recurrence had a peri-device leak and achieved LAAEI by the same PI after replacing with a larger size device and eliminating the peri-device leak. Another canine with early recurrence (1/6, 16.7%) failed to achieve LAAEI due to epicardial connection with persistent left superior vena cava. No coronary spasm, stenosis or other complications were observed. CONCLUSION: These results suggest that with proper device-tissue contact and pulse intensity, LAAEI can be achieved using this novel device without serious complications. The LAAp RT patterns observed in this study could inform and guide the adjustment of the ablation strategy.