超声造影评价心脏再同步化治疗对比格犬缺血性心肌灌注的作用

Impact of myocardial contrast echocardiography on evaluating the myocardial perfusion in Beagles with ischemic cardiomyopathy and cardiac resynchronization therapy

目的应用心肌造影超声心动图（MCE）定量评价心脏再同步化治疗（CRT）后心肌血流量的变化，以研究CRT是否能够改善心肌灌注。方法将12条比格犬随机分为A、B两组，分别结扎第一对角支，建立心肌梗死后心力衰竭的动物模型。随后A组植入三腔起搏器，行心脏再同步化治疗；B组亦植入三腔起搏器，但不启动起搏器。在基础状态、起搏器术前及起搏器术后4周，用MCE和斑点追踪显像技术定量评价心肌血流量（MBF值），环向、径向和纵向12节段达峰时间标准差（Cir12SD、R12SD和L12SD），探讨CRT对心肌灌注水平的影响。结果基础状态及CRT术前，A、B两组的左室射血分数（LVEF）、左室舒张末容积（LVEDV）、左室收缩末容积（LVESV）、Cir12SD和R12SD均无明显差异（P〉0．05）。CRT后4周，A、B两组的LVEF、LVEDV、LVESV、Cir12SD和R12SD分别为（58．8±8．2）％对（39．5±8．7）％，（28．2±2．9）ml对（34．2±2．5）ml，（13．9±2．6）ml对（21．5±4．7）ml，（29．1±6．6）ms对（46．5±10．1）mS和（36．1±10．7）ms对（67．6±11．2）ms（P均〈0．05）。基础状态下A、B两组的A、8和MBF值分别为（13．6±2．2）dB对（14．9±3．0）dB，（5．1±1．1）s-1对（4．8±2．1）s，（67．6±12．1）dg／S对（72．8±8．6）d]3／s（P〉0．05）。在CRT术前A组和B组的A、B和MBF值分别为（7．4±1．2）dB对（7．3±2．7）dB，（3．9±0．9）s。对（2．9±0．9）s，（23．4±4．2）dB／s对（22．2±4．1）dB／s（P均〉0．05）。在CRT术后4周A组的A、B和MBF值较B组显著提高，分别为（12．1±1．8）dB对（9．5±1．7）dB，（4．7±0，3）s-1对（3．1±0．8）S，（47．2±8．6）d]3／S对（29．5±4．2）dB／s（P均〈0．05）。结论心肌梗死后心力衰竭犬行心脏再同步化治疗，不仅能改善心脏收缩同步性，更能改善缺血心肌的心肌灌注。

Objective To investigate the impact of myocardial contrast echocardiography （MCE） on evaluating the myocardial perfusion in beagles with ischemic cardiomyopathy and cardiac resynchronization therapy （CRT） ,and to estimate the myocardial perfusion by myocardial blood flow （MBF） value. Methods Twelve adult beagles were randomly divided into two groups （CRT group and non-ClOT group）. Each beagle underwent a ligature in the first diagonal branch and a pacemaker was implanted. The pacing was started in CRT group,but was not started in non-CRT group. MCE and speckle tracking imaging were performed to evaluate the MBF value and circumferential strain （Cir12SD）,radial strain （R12SD） and longitudinal strain （L12SD） of 12 segments of left ventricle at baseline,before CRT,and 4 weeks after CRT. Results There was no significant difference of LVEF, LVEDV, LVESV, Cirl2SD, and R12SD between two groups at baseline or before CRT（ P 〉0.05）. After 4 weeks of CRT, LVEF, LVEDV, LVESV, Cir12SD, and R12SD in two groups were （58.8±8.2）% vs （39.5±8.7）%,（28.2±2.9）ml vs （34.2±2.5）ml,（13.9±2.6）ml vs （21.5 ± 4.7）m1,（29.1 ± 6.6）ms vs （46.5 ± 10.1）ms and （36.1 ± 10.7）ms vs （67.6 ± 11.2）ms（ P 0. 05）. A,β,and MβF value between two groups were （13.6 -± 2.2）dB vs （14.9 ± 3.0）dB,（5.1 ± 1.1）s -1 vs （4. 8 ± 2.1）s-1 , （67.6 ± 12.1）dB/s vs （72.8 ± 8.6）dB/s（ P 〈0.05） at baseline and were （7.4 ± 1.2）dB vs （7.3±2.7）dB,（3.9 ±0.9）s-1 vs （2.9± 0.9）s-l,（23.4±4.2）dB/s vs （22.2 ±4.1）dB/s （P 〈0.05） before CRT. After 4 weeks of CRT,A,13,and MBF value in CRT group were higher than those in non-CRT group （12.1 ± 1.8）dB vs （9.5± 1.7）dB,（4. 7 ± 0.3）s-1 vs （3.1 ± 0.8）s-1 , （47.2 ± 8.6）dB/s vs （29.5 ± 4.2）dB/s,all P 〈0.05）. Conclusions In beagles with ischemic cardiomyopathy,CRT can not only improve cardiac synchrony, but also increase myocardial perfusion.