超声消融犬心肌的实验研究(摘要)
作者：姚焰 王方正 张奎俊 王崇慧 田瑞国 孙瑞龙 陈新
单位：北京市，中国医学科学院 中国协和医科大学 心血管病研究所 阜外心血管病医院 临床电生理研究室(100037)
关键词：
目的 目的：超声波因其独特的机械、温热及空化效应，被认为是消融治疗心肌梗塞后室性心动过速的替代能量。本研究旨在观察各种物理因素对超声消融效果的影响，并验证超声消融心肌梗塞后慢性疤痕组织区的可行性。
方法：使用1.8 MHz超声，分别对①离体犬心肌标本：a 采用不同的声功率、时间、次数进行消融，部分标本在消融测量换能器—组织间温度；b 采用相同频率和声功率消融左、右心室肌；c 采用与组织接触(A型)和不直接接触(B型)的两种超声换能器消融；标本均以甲醛固定1～2周后测量损伤灶深度及体积。②在体部分：a 采用不同的声功率消融在体犬心室外膜，观察并对比心脏的组织学和电学损伤；b 对心肌梗塞后慢性疤痕区进行超声消融。
, 百拇医药
结果：离体部分：①超声消融心肌损伤灶的深度和体积随着声功率的增大而增加，其深度从3.0 W/cm2时的1.96±0.18 mm增至9.67 W/cm2时的6.31±0.58 mm,最深达8.3 mm;体积则从64.11±11.40 mm3增至538.51±82.63 mm3,不同功率之间的损伤灶深度和体积均有明显差异(P<0.001);随着消融时间从20 s延长至90 s,其损伤灶深度和体积分别由1.93±0.22 mm和58.79±13.94 mm3增至5.75±0.45 mm和445.78±82.46 mm3,差异均有显著性(P<0.001);随着重复消融次数的增加，损伤灶的深度和体积亦有增加，但在第4次消融后的增加量则不显著(P>0.05);温度与损伤灶的深度(r=0.461)或体积(r=0.255)之间的相关性并不如声功率或消融时间那样良好；②左心室肌标本的超声消融损伤灶体积(115.33±19.96 mm3比131.51±29.40 mm3,P<0.05)和深度(3.79±0.24 mm比4.19±0.30 mm,P<0.01)均较右心室肌小；③虽然B型换能器所造成的损伤灶的体积和深度均小于A型，但差异均无显著性(P>0.05)。在体部分：①消融区中心点和边缘处的动作电位幅度(APA)和除极速率(Vmax)降低均极显著(P<0.001),其损伤范围和程度随声功率或能量水平增高而增大，而APD90和APD50均无明显改变(P>0.05);②高能量超声在心肌梗塞后慢性疤痕区造成了明确的残存心肌和胶原纤维的坏死。
, 百拇医药
结论：①心肌损伤灶的深度和体积随着声功率、消融时间、重复消融次数的增加而增加；换能器—组织接触面温度并非决定消融效果的主要因素；②左、右心室肌纤维排列上的差异，可能会影响超声消融的效果；③在耦合良好时，不要求换能器与组织表面紧密接触；④超声消融可导致在体心肌不可逆的组织和电学损伤；⑤超声消融可在心肌梗塞后慢性疤痕造成明确的心肌和胶原纤维的坏死。
Experimental Study of Cardiac Ultrasound Ablation in Canine Heart (Abstract)
Department of Clinical Electrophysiology, Cardiovascular Institute and Fu Wai Hospital, CAMS and PUMC, Beijing (100037)
Yao Yan, Wang Fangzheng, Zhang Kuijun, et al.
, http://www.100md.com
Objective: Ultrasound is considered as an alternative enedrgy for post-myocardial infarction ventricular tachycardia due to its good penetration through tissues. This study was designed to observe the effects of acoustic power, duration, repetitive ablations, tissue-transducer interface temperature and different sites of the ultrasound ablation in vitro. The histological and electrical damages of ultrasound ablation and the feasibility of using ultrasound energy for chronic myocardial infarction scar ablation were also evaluated in vivo.
, 百拇医药
Methods: At 1.8 MHz frequency, Ultrasound ablation were conducted with: ① Different acoustic powers (3.0～9.67 W/cm2), duration (20～90 sec) and repetitive times (1～4); ② Lesion volume and depth were compared between right and left ventricular muscles; ③Two different types of transducers with (model A) and without (model B) direct tissue contact were used in vitro and ①Ultrasound ablation was applied on the epicardium to compare the histological and electrophysiological damages in ten canines; ②After chronic myocardial infarction, ultrasound ablation was applied on the scar regions in 5 canines in vivo.
, 百拇医药
Results: In vivo: ①While the acoustic power increased from 3.0 W/cm2 to 9.67 W/cm2, the lesion depth and volume increased from 1.96±0.18 mm and 64±11.40 mm3 to 6.31±0.58 mm and 538.51±82.63 mm3, respectively, and there were also significant differences between different powere levels; Similarly, while the ablation time was prolonged from 30 s to 90 s at fixed acoustic powere levels, the lesion depth and volume significantly increased from 1.93±0.22 mm and 58.79±13.94 mm3 to 5.75±0.45 mm and 445.78±82.46 mm3, respectively; Repetitive ablations resulted in larger lesion size but such increase was not significant after the fourth time ablation; Tissue-transducer interface temperature did not displayed a close relationship with the lesion size as acoustic power and ablation time did; ②Both the lesion depth (3.79±0.24 mm vs. 4.19±0.30 mm, p<0.01) and volume (115.33±19.96 mm3 vs. 131.51±29.40 mm3, p<0.05) on the left ventricular muscle were significantly smaller than those on right ventricle; ③Although the depth and volume casued by transducer model B were smalller than model A, such difference was not significant (p>0.05). in vivo: ① Ultrasound ablation significantly decreased the action potential amplitude (APA) and absolute rise of depolarization velocity (Vmax) at the central and edge points of ablation sites (p<0.001), while there were no significant changes with durations (APD90 and APD50); ② Ultrasound ablation resulted in necrosis of collagen fiber and residual myocardial cells.
, http://www.100md.com
Conclusion: ① The lesion sizes were increased along with the acoustic power, ablation duration and repetitive ablation times increase. Tissue-transducer interface temperature was not a major determinative factor of ablation effect; ② The differences between right and left ventricular myocardial architecture may result in different ablative effects; ③ The close tissue-transducer contact was not necessarily needed under good coupling; ④ Ultrasound ablation could result in irreversible histological and electrical damages in vivo and the size and extent were increased along with the energy intensity; ⑤ It could also cause necrosis of collagen and residual myocardium in cchronic infarction scar regions., http://www.100md.com
单位：北京市，中国医学科学院 中国协和医科大学 心血管病研究所 阜外心血管病医院 临床电生理研究室(100037)
关键词：
目的 目的：超声波因其独特的机械、温热及空化效应，被认为是消融治疗心肌梗塞后室性心动过速的替代能量。本研究旨在观察各种物理因素对超声消融效果的影响，并验证超声消融心肌梗塞后慢性疤痕组织区的可行性。
方法：使用1.8 MHz超声，分别对①离体犬心肌标本：a 采用不同的声功率、时间、次数进行消融，部分标本在消融测量换能器—组织间温度；b 采用相同频率和声功率消融左、右心室肌；c 采用与组织接触(A型)和不直接接触(B型)的两种超声换能器消融；标本均以甲醛固定1～2周后测量损伤灶深度及体积。②在体部分：a 采用不同的声功率消融在体犬心室外膜，观察并对比心脏的组织学和电学损伤；b 对心肌梗塞后慢性疤痕区进行超声消融。
, 百拇医药
结果：离体部分：①超声消融心肌损伤灶的深度和体积随着声功率的增大而增加，其深度从3.0 W/cm2时的1.96±0.18 mm增至9.67 W/cm2时的6.31±0.58 mm,最深达8.3 mm;体积则从64.11±11.40 mm3增至538.51±82.63 mm3,不同功率之间的损伤灶深度和体积均有明显差异(P<0.001);随着消融时间从20 s延长至90 s,其损伤灶深度和体积分别由1.93±0.22 mm和58.79±13.94 mm3增至5.75±0.45 mm和445.78±82.46 mm3,差异均有显著性(P<0.001);随着重复消融次数的增加，损伤灶的深度和体积亦有增加，但在第4次消融后的增加量则不显著(P>0.05);温度与损伤灶的深度(r=0.461)或体积(r=0.255)之间的相关性并不如声功率或消融时间那样良好；②左心室肌标本的超声消融损伤灶体积(115.33±19.96 mm3比131.51±29.40 mm3,P<0.05)和深度(3.79±0.24 mm比4.19±0.30 mm,P<0.01)均较右心室肌小；③虽然B型换能器所造成的损伤灶的体积和深度均小于A型，但差异均无显著性(P>0.05)。在体部分：①消融区中心点和边缘处的动作电位幅度(APA)和除极速率(Vmax)降低均极显著(P<0.001),其损伤范围和程度随声功率或能量水平增高而增大，而APD90和APD50均无明显改变(P>0.05);②高能量超声在心肌梗塞后慢性疤痕区造成了明确的残存心肌和胶原纤维的坏死。
, 百拇医药
结论：①心肌损伤灶的深度和体积随着声功率、消融时间、重复消融次数的增加而增加；换能器—组织接触面温度并非决定消融效果的主要因素；②左、右心室肌纤维排列上的差异，可能会影响超声消融的效果；③在耦合良好时，不要求换能器与组织表面紧密接触；④超声消融可导致在体心肌不可逆的组织和电学损伤；⑤超声消融可在心肌梗塞后慢性疤痕造成明确的心肌和胶原纤维的坏死。
Experimental Study of Cardiac Ultrasound Ablation in Canine Heart (Abstract)
Department of Clinical Electrophysiology, Cardiovascular Institute and Fu Wai Hospital, CAMS and PUMC, Beijing (100037)
Yao Yan, Wang Fangzheng, Zhang Kuijun, et al.
, http://www.100md.com
Objective: Ultrasound is considered as an alternative enedrgy for post-myocardial infarction ventricular tachycardia due to its good penetration through tissues. This study was designed to observe the effects of acoustic power, duration, repetitive ablations, tissue-transducer interface temperature and different sites of the ultrasound ablation in vitro. The histological and electrical damages of ultrasound ablation and the feasibility of using ultrasound energy for chronic myocardial infarction scar ablation were also evaluated in vivo.
, 百拇医药
Methods: At 1.8 MHz frequency, Ultrasound ablation were conducted with: ① Different acoustic powers (3.0～9.67 W/cm2), duration (20～90 sec) and repetitive times (1～4); ② Lesion volume and depth were compared between right and left ventricular muscles; ③Two different types of transducers with (model A) and without (model B) direct tissue contact were used in vitro and ①Ultrasound ablation was applied on the epicardium to compare the histological and electrophysiological damages in ten canines; ②After chronic myocardial infarction, ultrasound ablation was applied on the scar regions in 5 canines in vivo.
, 百拇医药
Results: In vivo: ①While the acoustic power increased from 3.0 W/cm2 to 9.67 W/cm2, the lesion depth and volume increased from 1.96±0.18 mm and 64±11.40 mm3 to 6.31±0.58 mm and 538.51±82.63 mm3, respectively, and there were also significant differences between different powere levels; Similarly, while the ablation time was prolonged from 30 s to 90 s at fixed acoustic powere levels, the lesion depth and volume significantly increased from 1.93±0.22 mm and 58.79±13.94 mm3 to 5.75±0.45 mm and 445.78±82.46 mm3, respectively; Repetitive ablations resulted in larger lesion size but such increase was not significant after the fourth time ablation; Tissue-transducer interface temperature did not displayed a close relationship with the lesion size as acoustic power and ablation time did; ②Both the lesion depth (3.79±0.24 mm vs. 4.19±0.30 mm, p<0.01) and volume (115.33±19.96 mm3 vs. 131.51±29.40 mm3, p<0.05) on the left ventricular muscle were significantly smaller than those on right ventricle; ③Although the depth and volume casued by transducer model B were smalller than model A, such difference was not significant (p>0.05). in vivo: ① Ultrasound ablation significantly decreased the action potential amplitude (APA) and absolute rise of depolarization velocity (Vmax) at the central and edge points of ablation sites (p<0.001), while there were no significant changes with durations (APD90 and APD50); ② Ultrasound ablation resulted in necrosis of collagen fiber and residual myocardial cells.
, http://www.100md.com
Conclusion: ① The lesion sizes were increased along with the acoustic power, ablation duration and repetitive ablation times increase. Tissue-transducer interface temperature was not a major determinative factor of ablation effect; ② The differences between right and left ventricular myocardial architecture may result in different ablative effects; ③ The close tissue-transducer contact was not necessarily needed under good coupling; ④ Ultrasound ablation could result in irreversible histological and electrical damages in vivo and the size and extent were increased along with the energy intensity; ⑤ It could also cause necrosis of collagen and residual myocardium in cchronic infarction scar regions., http://www.100md.com