国产可调节输出功率的双极射频消融装置的离体动物实验

In vitro animal test for domestic made bipolar radiofrequency ablation system with changeable radiofrequency output

目的 研究不同输出功率下,双极射频消融装置对不同厚度离体心房组织消融至透壁所需的时间及使用阻抗指标评价透壁性时的病理学检验,从而确定国产消融装置的合理输出功率.方法 20头猪屠宰后马上获取猪心,立即浸入4℃的生理盐水溶液中,清洗后制备离体心房组织.使用自行研制的输出功率可调式双极射频消融装置及消融钳,分别使用25 W、30 W及35 W的输出功率对离体心房组织进行消融.消融线间隔约5mm,彼此间平行.消融透壁的指标是消融时该处同时测定的电阻抗大于100 Ω.依次使用相同的输出功率,记录对不同厚度心房组织完成消融所需时间.消融完成后,沿两条消融线中点依次剪开心房组织,肉眼检查消融效果,测量消融线处组织厚度.按消融组织厚度,将心房组织分成＜2 mm、2～4 mm（≥2 mm,＜4 mm）、4～6 mm（≥4 mm,＜6 mm）及≥6mm4组.对应于不同输出功率和厚度,将心房组织分为12个区组.分别随机挑选每个区组的心房组织10块,将心房组织浸入多聚甲醛溶液,固定后心房组织使用石蜡切片,Mason三色法染色,显微镜下检验是否透壁.结果 实验共有350条消融线到达透壁指标.4～6 mm及＞6 mm组的心房组织消融完成时间明显长于＜2 mm组心房组织[（12.4±0.9）s比（24.3±0.3）s,P=0.042;（12.4±0.9）s比（35.9±0.3）s,P=0.001].消融完成时间在输出功率25 W与35 W间有显著差异[（28.9±0.5）s比（16.9±0.5）s,P=0.010].心房组织厚度与消融完成时间呈正相关.单次消融到达消融透壁指标时的病理透壁率为0～60％,随心房厚度增厚而降低,随输出功率增加而升高.结论 心房组织的消融完成时间随射频输出功率增加而缩短,并与心房组织厚度呈正相关.单次射频消融的透壁率较低.综合考虑消融所需时间、透壁率及安全性,输出功率在30～35 W是国产消融仪较为合理的射频输出功率.

Objective To investigate the duration of ablation for atrial tissue with various thickness under different output of radiofrequency （RF） by our domestic made RF ablation machine,and evaluate the accuracy of electrical resistance as the parameter of transmurality.Methods 20 cases of in vitro porcine heart were harvested right after animals were sacrificed.The in vitro hearts were washed in normal saline twice at 4 ℃.Atrial tissue was harvested then.RF was delivered by a domestic made RF ablation system by 25,30,and 35 watts of output.Ablation lines were made in parallel with the distance of 5 mm in between on atrial tissue.The ablation was terminated after electrical resistance of the ablated tissue reached over 100 Ω.The duration of ablation,the tissue thickness,and the corresponding RF output were recorded.The ablation line was excised for pathological section,transmurality was determined by Mason trichrome stain.Results 350 ablation lines were made successfully.Under the same RF output,the ablation duration was longer in the group of atrial tissue with the thickness between 4 and 6 mm,and thicker than 6 mm as compared with the duration of atrial tissue less than 2 mm in thickness [（12.4±0.9）s vs （24.3±0.3）s,P=0.042,（12.4±0.9）s vs （35.9±0.3）s,P=0.001].With the same tissue thickness,the duration of ablation was significantly different between groups of 25 W and 35 W output [（28.9±0.5）s vs （16.9±0.5）s,P=0.010].The duration of ablation was positively correlated to the thickness of atrial tissue.The pathological transmurality varied from 0 to 60%.It increased with the higher output,and decreased with the thicker atrial tissue.Conclusion The duration of ablation is determined by the thickness of atrial tissue and the RF output.The pathological transmurality is relatively low with single ablation.30 and 35 W are optional RF output,considering the safety of ablation,reasonable ablation duration and pathological transmurality.