应变及应变率成像定量评价容量负荷过重对左室收缩功能的影响

Quantitative evaluation of left ventricular contractility in patients with volumetric overload by strain and strain rate imaging

目的采用应变及应变率成像定量评价不同容量负荷状态下心肌收缩性能的变化规律,为临床合理选择手术适应证提供客观依据。方法左室容量负荷过重患者44例,依据左室舒张末期容积指数(LVEDVI)分为LVEDVI正常组、LVEDVI增大组和LVEDVI显著增大组三组,正常对照组45例,对比观察各组左室壁收缩期应变率峰值(PSSR)和应变峰值(PSS),并对所有患者进行术前及术后对比。结果①LVEDVI正常组PSSR和PSS值较对照组无显著性差异,其手术前后无显著改变;LVEDVI增大组和LVEDVI显著增大I组的PSSR和PSS值在术前较对照组显著增加,术后随着LVEDVI的减小而恢复正常;LVEDVI显著增大II组的PSSR和PSS值术前较对照组有减低趋势,术后没有显著改变。②左室壁PSSR值及PSS值在LVEDVI正常组与LVEDVI呈正相关(r分别为0.80和0.83,P<0.05),在LVEDVI增大组二者相关性不显著(r分别为0.46和0.42,P>0.05),而在LVEDVI显著增大组其与LVEDVI呈负相关(r分别为-0.72和-0.53,P<0.05)。结论应变及应变率成像能够准确定量评价左室收缩功能,左室壁PSSR值及PSS值随左室容量负荷程度增大而发生规律性变化。

Objective To evaluate the effect of volumetric overload on myocardial contractility of left ventricle （LV） using strain and strain rate imaging （SRI） and to provide useful information for therapeutic strategies. Methods The subjects in-cluded 44 patients with LV volumetric overload and 45 normal volunteers as controls. Based on LV end-diastolic volume index （LVEDVI）, the patients were divided into three groups： LVEDVI normal group, LVEDVI augmentation group and marked LVEDVI augmentation group. The peak systolic strain rate （PSSR） and the peak systolic strain （PSS） from SRI curve were obtained and compared among the groups. In addition, the change of these parameters pre-and post-operation was also analyzed. Results ① Compared with control group, PSSR and PSS showed no change in LVEDVI normal group both pre-and post-operation but they were significantly higher in LVEDVI augmentation group and marked LVEDVI augmentation group Ⅰ pre-operation and returned to normal level post-operation as LVEDVI decreased significantly. In marked LVEDVI augmentation group Ⅱ, PSSR and PSS were lower both pre-and post-operation and showed no change post-operation although LVEDVI decreased after operation. ② PSSR and PSS were correlated positively to LVEDVI （r= 0.80 and 0.83, P〈0. 05） in LVEDVI normal group but negatively to LVEDVI （r=-0.72 and -0. 53, P〈0.05） in marked LVEDVI augmentation group while in LVEDVI augmentation group, no significant correlation was found （r=0.46 and 0.42, P〈0.05）. Conclusion SRI can be used for assessment of myocardial contraction in clinical setting and LV PSSR and PSS change periodically according to LV volumetric overload.