活体超声心肌消融的生物学效应

Biologic effects of ventricular myocardial ablation in vivo induced by ultrasound wave

目的 探讨超声消融活体心肌的效应特征 ,提供导管超声用以治疗心律失常的实验基础。 方法 用 10 .4MHz的超声导管消融 10只活体犬心肌 ,观察消融深度、形态和温度变化及其与射频消融心肌效应的差异。 结果 超声在活体犬可产生深达 10 mm的心肌消融 ,消融深度与消融时间呈良好相关且边界清晰 ;其热中心在心肌内部。而射频消融深度明显低于超声 ,其热中心在消融的心肌表面。 结论 超声可产生边界清晰且深入的心肌消融 ,消融深度可控 ,提示超声作为导管消融较为安全的能量适于消融深部病灶。

Objective To investigate the biologic effects of high freqency ultrasound wave ablating ventricular myocardium in vivo. Methods The ventricular myocardium in 10 anaesthetized canines was ablated by transcatheter ultrasound wave with freqency of 10 4 MHz.The depth and shape of the ablated lesions were observed,and the temperature at the ablation site was measured.The lesions created by ultrasound wave and radiofrequency wave on myocardium in vitro were also studied and compared. Results In vivo ultrasound ablation of ventricular myocardium could produce lesions of 10 mm in depth with clear cut border.The depth had linear relationship with energy application duration.The heating center caused by ultrasound wave located in the deep layer of myocardium.Contrarily,radiofrequency ablation produced wider,shallower lesions,and the heating center located at the myocardial surface of the ablation site. Conclusions High frequency ultrasound wave ablation can produce lesion deep enough in the myocardium,and the depth is controllable,implying that it can be used to ablate a focus in deep layer of ventricular myocardial.