摘要目的:探究脉冲电场消融（PFA）中电极-组织贴靠力（CF）和发放次数对犬左心房（LA）和肺静脉前庭损伤（PVO）的影响。方法:本研究为随机对照研究。选取4只拉布拉多犬，雌雄各2只，术前体重30~40 kg。采用三维电解剖标测系统定位4只实验犬左心房（LA）和肺静脉前庭（PVO）后，通过CF感知磁定位PFA导管进行脉冲电场发放。根据CF大小分为低CF（LCF，1~3 g）和高CF（HCF，10~20 g），根据脉冲电场发放次数分为低量（LD，×3）高量（HD，×10），每组消融位点数20个。选取LA和PVO位点消融后完全透壁位点10个，记录和比较消融前后的电压值和阻抗值变化。1周后通过犬消融灶中心心肌病理组织切片评估消融损伤深度。结果:①LA-HCF-LD组透壁率和消融损伤深度均高于LA-LCF-LD组［90.0%（18/20）对20.0%（4/20）， P<0.001；（9.25±0.12）mm对（9.03±0.16）mm， t=6.11， P<0.001］；LA-LCF-HD组透壁率和消融损伤深度均高于LA-LCF-LD组［70.0%（14/20）对20%（4/20）， P=0.004；（9.22±0.09）mm对（9.03±0.16）mm， t=5.44， P<0.001］；LA-HCF-HD组的透壁率和消融损伤深度均高于LA-LCF-HD组［100.0%（20/20）对70.0%（14/20）， χ2=7.06， P=0.008；（9.37±0.55）mm对（9.22±0.9）mm， t=9.60， P<0.001］。PV-LCF-HD组、PV-HCF-LD组、PV-HCF-HD组的透壁率均为100.0%（20/20），高于PV-LCF-LD组［85.0%（17/20）］，差异均无统计学意义（ χ2=3.24， P>0.05）。PV-HCF-HD组消融损伤深度高于PV-LCF-LD组［（3.47±0.25）mm对（3.60±0.14）mm， t=1.91， P=0.060］及PV-HCF-LD组［（3.55±0.15）mm对（3.60±0.14）mm， t=2.23， P<0.05］，PV-LCF-LD组与PV-LCF-HD组、PV-HCF-LD组间消融损伤深度比较差异均无统计学意义（ P>0.05）。②与LA-LCF-LD组相比，PV-LCF-LD组的透壁率明显较高［20.0%（4/20）对85.0%（17/20）， P<0.001］，其余3组透壁率差异均无统计学意义（ P>0.05）。与LA相比，PVO后壁的组织厚度较薄［（3.53±0.18）mm对（9.29±0.12）mm， t=241.84， P<0.05］。③LA与PVO后壁消融3次和10次后的电压较消融前均明显下降，LA和PVO后壁阻抗消融前后变化差异无统计学意义（ P>0.05）。 结论:CF和脉冲电场发放次数在PFA损伤LA和PVO中起关键作用，在低CF低脉冲发放次数时，PVO透壁性优于LA，可能与两组织间厚度不一有关。

abstractsObjective:To investigate the impact of electrode-tissue contact force (CF) and pulse delivery times on lesion formation during pulse field ablation (PFA) in canine left atrium (LA) and pulmonary vein ostium (PVO).Methods:This study was designed as a randomized controlled trial(RCT).This was an experimental study involving four dogs [(30-40 kg, two males and two females)] that underwent LA and PVO mapping using a three-dimensional electroanatomical mapping system. They were divided into a low-CF(LCF, 1-3 g) group and a high-CF (HCF, 10-20 g) group, according to the size of CF, and based on the number of pulse deliveries into the low-dose (LD, ×3) group and the high-dose (HD, ×10) group. Each group included 20 ablation sites. After ablation, 10 sites with confirmed full-thickness lesions in the LA and PVO were selected for voltage and impedance measurements before and after ablation. One week post-ablation, the depth of ablation injury was evaluated by histopathological sections of the myocardium in the center of the ablation area.Results:① The transmurality rate of the LA-HCF-LD group and the ablation lesion depth were both higher than those of the LA-LCF-LD group [90.0% (18/20) vs. 20.0% (4/20), P<0.001; (9.25±0.12) mm vs. (9.03±0.16) mm, t=6.11, P<0.001]. The transmurality rate of the LA-LCF-HD group and the ablation lesion depth were both higher than those of the LA-LCF-LD group[70.0% (14/20) vs. 20% (4/20), P<0.001; (9.22±0.09) mm vs. (9.03±0.16) mm, t=5.44, P<0.001]. The transmurality rate of the LA-HCF-HD group and the ablation lesion depth were both higher than that of the LA-LCF-HD group[100.0% (20/20) vs. 70.0% (14/20), χ2=7.06, P=0.008; (9.37±0.55) mm vs. (9.22±0.9) mm, t=9.60, P<0.001]. The transmurality rates of the PV-LCF-HD, PV-HCF-LD, and PV-HCF-HD groups were all 100.0% (20/20), higher than that of the PV-LCF-LD group [85.0% (17/20)], but the differences were not statistically significant ( χ2=3.24, P>0.05). The ablation lesion depth of the PV-HCF-HD group was higher than that of the PV-LCF-LD group [(3.47±0.25) mm vs. (3.60±0.14) mm, t=1.91, P=0.060] and the PV-HCF-LD group [(3.55±0.15) mm vs. (3.60±0.14) mm, t=2.23, P<0.05], while the differences in ablation lesion depth between the PV-LCF-LD group and the PV-LCF-HD group, as well as the PV-HCF-LD group, were not statistically significant ( P>0.05).② Compared with the LA-LCF-LD group, the transmurality rate of the PV-LCF-LD group was significantly higher[20.0% (4/20) vs. 85.0% (17/20), P<0.001], while the differences in transmurality rates among the other three groups were not statistically significant ( P>0.05). Compared with LA, the tissue thickness of the posterior wall of PVO was thinner [(3.53±0.18) mm vs. (9.29±0.12) mm, t=241.84, P<0.05].③ The voltages of LA and the posterior wall of PVO after 3 and 10 ablations were significantly lower than before ablation, and the changes in impedance before and after ablation in LA and the posterior wall of PVO were not statistically significant ( P>0.05). Conclusion:CF and the number of pulsed electric field applications play a crucial role in PFA-induced injuries to the LA and PVO. At low CF and low pulse counts, the PVO exhibits better transmurality than the LA, which may be attributed to the thickness difference between the two tissues.