超声辐照联合微泡消融活体犬心肌

目的探讨低能量超声辐照联合微泡消融活体犬心肌的可行性。方法将20只杂种犬随机分为超声联合微泡组(US+MB组)、单纯超声组(US组)、单纯微泡组(MB组)和对照组,每组5只。在心腔内超声(ICE)监控下,将自制多功能ICE导管送入犬左心室。对US+MB组犬于左心室前壁注射0.1ml微泡,以0.3 W/cm2声能对注射部位辐照30s;US组以相同条件辐照,但不注射微泡;MB组仅注射微泡;对照组仅插入导管,不进行其他处理。术后第3天处死动物,进行心脏形态学及组织学观察。结果肉眼见US+MB组微泡注射部位心肌出现苍白色消融灶,镜下见心肌细胞核固缩、核碎裂等特征;US组、MB组及对照组动物心脏形态学及组织学均未见明显异常。结论微泡能提高超声消融效果,实现低能量超声消融心肌组织,减少心内膜损伤,提高心肌消融的安全性。

Ultrasound irradiation combined with microbubbles in myocardium ablation of canine in vivo

Objective To explore the feasibility of low-dose ultrasound irradiation combined with microbubbles in myocar-dium ablation of canine in vivo. Methods Twenty canines were randomly divided into ultrasound＋microbubbles （US＋MB） group, ultrasound （US） group, microbubbles （MB） group and control group （each n=5）. The intracardiac eehocar-diography （ICE） catheter was delivered into left ventricle. In US＋MB group, canine myocardia were exposed to ultrasound irradiation （0.3 W/cm^2） for 30 s after intramyocardial injection of 0. 1 ml microbubbles at anterior wall of left ventrium. Animals in US group and MB group received simple ultrasound irradiation or mierobubbles injection, respectively, while in control group received catheterization only without other management. All the animals were executed on the 3th day. The myocardium was harvested for morphological and histological observation. Results Pale ablation lesions were observed at the region of microbubbles injection with visual inspection, and nuclear condensation and fragmentation in cardiac muscle cells were found under microscope in US＋MB group. No obvious abnormality of the myoeardia was found in US group, nor in MB group. Conclusion Microbubbles can increase the efficiency of ultrasound ablation, achieving myocardium abla-tion under low ultrasound energy, improving the safety of myocardium ablation.