探讨梗阻性与非梗阻性肥厚型心肌病左心室应变力的差异

Difference in myocardial strain between obstructive hypertrophy cardiomyopathy and nonobstructive hypertrophy cardiomyopathy

目的·探讨梗阻性与非梗阻性肥厚型心肌病(HCM)患者左心室应变力的改变及其差异。方法·序贯入组48例左心室射血分数保留(LVEF>50%)的HCM(梗阻性18例、非梗阻性30例)和25例健康人,采用心脏磁共振成像(MRI)扫描,测量并比较左心室整体纵向应变(GLS)、径向应变(GRS)与周向应变(GCS),以及LVEF、左室舒张末容积(LVEDV)、左室心肌质量(LVM)、左室舒张末容积指数(LVEDVI)、左室心肌质量指数(LVMI)。依据美国心脏协会17节段法则测量左心室中段径向应变(m RS)、周向应变(m CS)及径向最大位移。结果·(1)梗阻性HCM患者LVEF显著高于非梗阻性及正常组(P<0.05),2组HCM患者LVM及LVMI均显著高于正常组(均P<0.01)。(2)与梗阻性HCM患者相比,非梗阻性HCM患者的左心室整体应变参数(GLS、GRS、GCS)均明显降低(均P<0.05),且2组均低于正常组,差异具有统计学意义(均P<0.05)。(3)与梗阻性HCM患者相比,非梗阻性HCM患者的左心室节段性心肌应变力,即左心室m CS及m RS显著降低(均P<0.05),且2组均低于正常组(均P<0.05)。非梗阻性HCM患者左心室中段心肌径向最大位移显著低于梗阻性HCM患者及正常组(均P<0.05),梗阻性HCM患者与正常组间差异无统计学意义(P>0.05)。结论·在LVEF保留情况下,非梗阻性HCM患者左心室壁应变力较梗阻性HCM患者显著降低,可能是导致2种类型HCM患者临床预后不同的原因,提示在评价HCM心肌做功方面,心室室壁应变力较射血分数更敏感。

Objective·To investigate the difference in myocardial strain of left ventricle between obstructive hypertrophy cardiomyopathy(HCM)and nonobstructive HCM.Methods·Cardiac magnetic resonance imaging(MRI)exam was performed on48sequential enrolled patients with HCM(18with obstructive HCM,and30with nonobstructive HCM),whose left ventricular ejection fractions(LVEF)were over50%.Twenty-five healthy volunteers were examined as normal controls.Global longitudinal strain(GLS),global radial strain(GRS),global circumferential strain(GCS),LVEF,left ventricular end diastolic volume(LVEDV),left ventricular mass(LVM),left ventricular end diastolic volume index(LVEDVI),and left ventricular mass index(LVMI)were collected and compared.Radial strain,circumferential strain and peak radial displacement were also measured in medial segment of left ventricle according to American Heart Association(AHA)17-segment model.Results·①LVEF of the patients with obstructive HCM was bigger than those of nonobstructive HCM patients and control group(P<0.05).LVM and LVMI of the HCM groups were bigger than those of control group(P<0.01).②Left ventricle GLS,GRS,and GCS significantly decreased in the patients with nonobstructive HCM compared to those with obstructive HCM(P<0.05).The three parameters of two HCM groups were significantly lower than those of healthy volunteers(P<0.05).③Compared with obstructive HCM patients,the segmental parameters of left ventricule,the medial segment circumferential strain and radial strain of nonobstructive HCM patients significantly decreased(P<0.05),and the two parameters of both HCM groups were lower than those in healthy volunteers.Compared with obstructive HCM patients and healthy volunteers,peak radial displacement of left ventricule medial segment in nonobstructive HCM witnessed a significant decrease,while no significant difference was observed between obstructive HCM patients and healthy volunteers.Conclusion·In the LVEF preserved HCM patients,the myocardial strain of left ventricle in nonobstructive HCM patients decrease significantly than that in obstructive HCM patients,which may result in the different clinical outcomes in two types of HCM patients.It is suggested that the myocardial strain is more sensitive than ejection fraction in the evaluation of myocardial performance of HCM patients.