基于三维斑点追踪的左心室扭转功能预测心脏再同步化治疗疗效的实验研究

Prediction of treatment response for cardiac resynchronization therapy by left ventricular twist using three dimensional speckle tracking imaging in a heart failure canine model

目的应用超声三维斑点追踪技术研究快速起搏诱发心力衰竭比格犬心脏再同步化治疗（CRT）前后左心室扭转运动的变化和预测CRT疗效的扭转参数。方法22只成年比格犬以右心室快速起搏3周诱发心力衰竭，其中15只接受CRT治疗，7只作为对照。在基线、快速起搏3周和CRT2周时采集经胸左心室全容积图像，应用Tom—Tec4DLVAnalysis3．0软件分析，自动计算左心室心尖部和心底部旋转角度峰值（AP—Prot、MV—Prot）、左心室扭转角度峰值（Ptw）、左心室扭转力矩峰值（Ptor）等；探索预测心力衰竭比格犬CRT疗效的左心室扭转参数。结果经CRT治疗2周，心力衰竭比格犬左室射血分数（LVEF）、左室收缩末期容积（LVESV）明显改善（P均〈O．05）。以LVEsV缩小≥15％作为CRT治疗有效的标准将接受治疗的比格犬分为有效组（9只）与无效组（6只），两组在接受CRT治疗前PtwF（7．43±0．61）。对（6．06±0．89）°，P〈O．01]与PtorE（1．43±0．45）。／cm对（O．67±0．36）。／cm，P=0．oC差异存在统计学意义，且Ptw与Ptor对CRT疗效具有预测价值，敏感性分别为89％和85％，特异性分别为83％和84％。结论超声三维斑点追踪技术能够用于评价心力衰竭比格犬CRT前后左室扭转运动；左室整体扭转功能对CRT疗效具有预测价值。

Objective To assess left ventricular （LV） twist in a rapid pacing induced heart failure canine model undergoing cardiac resynchronization therapy （CRT） by three-dimensional speckle tracking imaging （3I）-STI）. Methods Rapid right ventricular pacing （RVP） was utilized in 22 adult beagle dogs for 3 weeks to induce heart failure. Then 15 dogs received CRT for 2 weeks and others were treated as control. Apical full-volume acquisition of the LV was obtained in conscious animals at baseline, the end of 3-week RVP and the end of 2-week CRT. Peak LV apical （AP-Prot） and basal rotation （MV-Prot） along with peak twist （Ptw） and torsion （Ptor） were automatically calculated by TomTec 4D LV Analysis 3.0 software to identify the ideal parameter in predicting treatment response of CRT. Results After 2 weeks of CRT,LV ejection fraction（LVEF） increased and LV end-systolic volume（LVESV） decreased significantly in dogs with heart failure. CRT treatment response, defined as improvement of LVESV^IS~,was observed in 9 dogs. Significant difference was found in Ptw [-（7.43 -＋ 0.61） vs （6.06 ＋ 0.89）~, P %0.05] and Ptor [（1.43 -＋ 0.45） vs （0.67 ＋ 0.36）~/cm, P %0.05] between responders and nonresponders. Ptw and Ptor predicted CRT response with satisfying sensitivity as 89~ and 85~, specificity as 83~ and 84%, respectively. Conclusions Peak twist and torsion evaluated by 3D-STI represented overall LV twist and demonstrated potential prediction value for treatment response of CRT.