超声斑点追踪成像定量评价左心室容量负荷过重患者左心室收缩功能

Quantitative evaluation of left ventricular systolic function in patients with volumetric overload by speckle tracking echocardiography

目的 应用斑点追踪成像技术定量评价左室容量负荷过重患者左室心肌收缩功能.探讨随左室容量负荷增大,心肌径向应变、应变率的变化情况及其与容量负荷之间的相关性.方法 病例组为左室容量负荷增大患者共77例;正常对照组为年龄及性别与病例组匹配的健康志愿者30例.所有受检者行超声心动图检查,获取胸骨旁左室短轴二尖瓣环、乳头肌、心尖部平面二维动态图像.应用二维应变分析软件分析短轴3个平面整体应变、应变率（GRS.GRSr）.采用双平面Simpson法测量左室舒张末容积（LVEDV）.用体表面积校正得到左室舒张末容积指数（LVEDVI）.根据正常LVEDVI将病例组分为6个亚组：临界组（LVEDVI≤90ml/m2）,A组（LVEDVI：91～120 ml/m2）,B组（LVEDVI：121～150ml/m2）.C组（LVEDVI：151～180ml/m2）.D组（LVEDVI：181～210 ml/m2）,E组（LVEDVI＞210ml/m2）.根据左室射血分数（LVEF）将病例组分为心功能正常组（Ⅰ组）、心功能减低组（Ⅱ组）.结果 ①临界组三个平面上述参数与正常对照组比较无明显差异（P ＞0.05）.A、B、C组上述参数较正常对照组显著增大（P＜0.05）.在临界组～C组中可观察到随LVEDVI增大,3个平面GRS、GRSr呈进行性增大.E组3个平面上述各参数较A、B、C、D组及正常对照组明显减小（P＜0.05）;在C～E组中可观察到随LVEDVI的增加,GRS、GRSr逐渐减小.②Ⅰ组3个平面GRS、GRSr较正常对照组及Ⅱ组增大（P＜0.01）;Ⅱ组3个平面GRS、GRSr较正常对照组及Ⅰ组明显减低（P＜0.01）.③二尖瓣环平面GRS在A、B组与LVEDVI呈明显正相关（r=0.79.0.77,P＜0.05）;C、D组二者相关性不显著（r=0.32,-0.12,P＞0.05）;E组与LVEDVI呈负相关（r=-0.54.P＜0.05）.乳头肌平面GRS在A、B、C组与LVEDVI呈明显正相关（r=0.55,0.64,0.76,P＜0.05）;D组二者相关性不明显（r=-0.35,P＞0.05）;E组二者呈明显负相关（r=-0 .70,P＜0.05）.心尖部平面GRS在A、B、C组与LVEDVI呈明显正相关（r=0.74,0.79,0.71,P＜0.05）;D组二者呈明显负相关（r=-0.73,P＜0.05）;E组二者无明显相关性（r=-0.39,P＞0.05）.LVEDVI为180～190ml/m2,乳头肌平面GRS达最大值约93%;心尖部GRS达最大值约62%;LVEDVI为150～160ml/m2时二尖瓣环平面GRS达到最大约63%.结论 左室心肌径向应变、应变率随左室容量负荷增大而发生规律性变化.超声斑点追踪成像技术可定量测量左室心肌应变、应变率,为临床评价左室收缩功能提供了一种无创性新方法.

Objective To assess global systolic function of left ventricle （LV） using speckle tracking echocardiography in patients who are left volumetric overload and to establish the correlativity between strain and left ventricle end-diastolic volume index （LVEDVI）. Methods Seventy-seven patients who were left volumetric overload and 30 normal volunteers were enrolled in this study. Respective 3 high frame rate （＞ 100 frames/s） 2D images were recorded from the left ventricular short axis views： the levels of mitral valve annulus, papillary muscle and apex. Three global peak systolic radical strain and strain rate were measured using 2D strain imagirg. LVEDV was obtained by two-plane Simpson method and LVEDVI was obtained by normalized LVEDV with surface body area. Patients were divided into 6 groups： transitionalgroup,group A （LVEDVI：90- 120 ml/m2）,group B （LVEDVI： 121 - 150 ml/m2 ）,group C （LVEDVI：151 -180 ml/m2）,group D （LVEDVI： 181 - 210 ml/m2）,and group E （LVEDVI＞210 ml/m2）. Patients were divided into two groups by left ventricular ejection fraction （LVEF）： group Ⅰ （LVEF≥ 50 % ）, group Ⅱ （LVEF＜50％）. Results ①Compared with normal control group,GRS,GRSr in transitional group showed no change at three short axis levels （P ＞0.05）. The above parameters in group A, B and C were significantly higher than those in normal control group（ P ＜0. 01 ）. In transitional group,group A,B and C,GRS, GRSr of three short axis gradually increased with LVEDVI augmentation. Compared with group A, B,C,D and normal control group,the above parameters of 3 short aixs in group E were decreased（ P ＜0. 01 ）,which gradually decreased in group C, D, E with LVEDVI augmentation. ②GRS,GRSr of 3 short axis views in group Ⅰ were more significantly high than those in group Ⅱ and normal control group. The parameters above were significantly low in group Ⅱ （ P ＜0.01）. ③In group A,B,C,GRS of papillary muscle and apex levels were correlated positively to LVEDVI （ rpapillary muscle = 0.55,0.64,0.76 and rspex = 0. 74, 0. 79,0.71,P ＜0.05） ; In group D, there was no correlativity between GRS of papillary muscle and LVEDVI（ r =- 0.35, P ＞ 0.05） while negative correlativity was established in apex level（ r = - 0.73, P ＜ 0. 05）. In group E,the negative correlativity was found between GRS of papillary muscle and LVEDVI（ r = -0. 70,P ＜0.05） while no correlativity was established in apex level（ r = - 0.39, P ＞0. 05）. GRS of mitral valve annulus was correlated positively to LVEDVI in group A, B（ r = 0.79, 0.77, P ＜ 0.05） and had no correlativity in group C,D. The negative correlativity between them was found in group E（ r = - 0. 54, P ＜0.05）. At LVEDVI： 180- 190 ml/m2 ,GRS of papillary muscle and apex level reach the peak point about 93% and 62% ;GRS of mitral valve annulus level reach the peak about 63% at LVEDVI 150 - 160 ml/m2.Conclusions Radial strain,strain rate change periodically with LV volume overload. Wall motion of left ventricle can be evaluated accurately by speckle tracking echocardiography, which provide useful modality for evaluation cardiac systolic function.