经心外膜聚焦超声环肺静脉消融与左房盒式消融治疗犬心房颤动的比较研究

目的探讨聚焦超声经心外膜的环肺静脉消融(CPVa)和左房盒式消融(BOXa)两种不同术式对心房颤动(简称房颤)的影响。方法成年杂种犬20只,随机分为两组,建立肺静脉起源的阵发性房颤模型后,直视下分别行CPVa和BOXa。测定消融前、后左房有效不应期(LAERP)、计算房颤诱发率、房颤持续时间,术毕行组织学检查。结果所有犬均能诱发出肺静脉起源的阵发性房颤,房颤终止后的LAERP较基线水平显著缩短(CPVa组:140±10msvs102±10ms;BOXa组:139±11msvs105±8ms;P均<0.01),但消融前后的LAERP并无显著性差异。消融后两组的房颤诱发率均较消融前显著降低(CPVa组:98%vs28%;BOXa组:97%vs14%;P均<0.01),房颤持续时间均显著缩短(CPVa组:233±40svs70±29s;BOXa组:240±41svs34±22s;P均<0.01);部分犬可见肺静脉-心房双向电传导阻滞;消融后BOXa组房颤诱发率和房颤持续时间低于/短于CPVa组(P<0.05)。消融后焦域内的组织呈凝固性坏死。结论经心外膜聚焦超声CPVa可显著降低房颤诱发率和缩短房颤持续时间,而BOXa则可进一步提高成功率。

The comparsion of epicardial focused ultrasound circumferential pulmonary veins ablation and box ablation for at-rial fibrillation in dogs

Objective To explore the feasibility of focused ultrasound ablation(FUA)on paroxysmal atrial fibrillation(AF),and compare the efficacy of circumferential pulmonary veins ablation(CPVa)and box ablation of left atrium(BOXa).Method Twenty mongrel dogs were studied.CPVa or BOXa were performed with the FU catheter after the paroxysmal AF models established,and the epicardial electrograms were recorded with the quadripolar electrode catheter placed at pulmonary veins(PV)and left auricular appendage(LAA).Left atrial effective refractory period(LAERP)was measured.The inducibility and lasting time of AF were also assessed.The histology of lesions was studied after the two procedures.Results Paroxysmal AF arising from the PVs was induced in all the dogs.After the models were successfully established,the LAERP was significantly shorter than before,but there was no significant change in both groups.Bidirectional conduction blocks were achieved in some of the two groups after FUA.The inducible rates of AF in the two groups were:98%±4% vs 28%±10% in CPVa group,P<0.01,97%±4% vs 14%±7% in BOXa group,P<0.01,both of them were decreased significantly,and the lasting times of AF were 233±40s vs 70±29s,in CPVa,P<0.01;240±41s vs 34±22s,in BOXa,P<0.01.Inducibility(P=0.021)and lasting time(P=0.048)of AF after FUA were significantly lower in group CPVa than those of BOXa.Histological evaluation of the lesions showed coagulated necrosis after FUA.Conclusions AF can be eliminated feasibly and efficiently by CPVa and BOXa,and the latter is more effective.