实时三维超声和斑点追踪显像预测心脏再同步化治疗疗效的实验和临床研究

Experimental and clinical studies of prediction of response to cardiac resynchronization therapy by real-time three-dimensional echocardiography and speckle tracking imaging

目的应用实时三维超声心动图（RT-3DE）和斑点追踪显像（STI）评价左心室同步性，以探索检测心脏再同步化治疗（cardiac resynchronization therapy，CRT）疗效的有效方法。方法动物实验对象为21条比格犬，随机分为A组（CRT组，10条），B组（心衰组，7条）和C组（对照组，4条）三组，临床研究对象为70例完成CRT术前及术后6个月随访的患者。以左室收缩末容积（LVESV）缩小15％为CRT治疗有效。评价同步性的超声参数包括RT-3DE评价左室16节段达最小收缩容积时间的标准差及其与心动周期的比值（Tmsv-16SD，SDI），STI评价犬左窒乳头肌水平6节段ORS波起点至径向应变和圆周应变达峰时间的标准差与心动周期的比值（Trs-6SD、Tcs-6SD）。结果动物实验的Tmsv-16SD、Trs-6SD、Tcs-6SD与左室射血分数（LVEF）呈负相关（r分别为-0．86、-0．75、-0．83，P均〈0．01），Trs-6SD对CRT疗效最有预测价值，当Trs-6SD≥12．2％时，预测CRT有效的敏感性和特异性分别为83．3％和i00％。临床研究显示，SDI最有预测价值，当其临界值为6．55％时，预测CRT有效的敏感性为80．0％，特异性为81．8％。结论RT-3DE和STI能有效评价左室内不同步，有望成为预测CRT疗效的有效方法。

Objective To investigate new parameters to predict the response to cardiac resynchronization therapy （CRT） by using real-time three-dimensional echocardiography （RT3DE） and speckle tracking imaging（STI）. Methods Twenty-one adult beagle dogs were divided into three groups： group A （CRT group, n = 10） ,group B （heart failure group, n = 7） and group C （control group, n = 4）. Seventy patients who accepted CRT and were followed up 6 months after CRT were enrolled. Response to CRT was defined as a≥15 % decrease in left ventricular end-systolic volume. RT-3DE parameters were the dispersion of time to minimum regional volume for 16 segments （Tmsv16-SD） ,and the ratio of Tmsv16-SD to R-R interval （SDI）. STI parameters were the ratios of standard deviation of the time to peak radial and circumferential strain at midventricular level to R-R interval （Trs-6SD,Tcs-6SD）. Results In experimental study,Tmsv-16SD, Trs-6SD, Tcs-6SD had negative relationship with left veutricular ejection fraction （r were - 0.86, - 0.75, - 0.83 respectively, all P 〈0.01）. Trs-6SD was the strongest predictor to CRT. A cut-off value of Trs-6SD≥12.2% was able to predict response to CRT with a sensitivity of 83.3M and a specificity of 100%. Clinical studies found SDI was the strongest predictor to CRT. A cut-off value of SDI≥6.55% was able to predict response to CRT with a sensitivity of 80.0% and a specificity of 81.8%. Conclusions RT-3DE and STI can assess left ventrieular dyssynchrony, and are promising methods to predict the response to CRT.