Evaluation Of Left Ventricular Systolic Function In Different Layers Myocardium By Using Two-dimensional Layer-specific Strain In Patients With Apical Hypertrophic Cardiomyopathy

Objective:To investigate the clinical value of two-dimensional layer-specific strain in evaluating left ventricular systolic function of different layers myocardium in patients with apical hypertrophic cardiomyopathy.Methods:A group of twenty ApHCM patients were enrolled in this study from June 2016 to December 2017 and twenty of them were selected by clinical and Trans Thoracic Echocardiography.All the HCM patients were matched with either the diagnosis by Trans Thoracic Echocardiography,which the left ventricular apical maximum wall thickness more than 15 millimetre or the ratio of the left ventricular apical maximum wall thickness and the left ventricular posterior wall thickness greater than 1.3 while the other position of the left ventricular wall thickness less than 15 millimetre.All standard three consecutive cardiac cycles of measurements were obtained from the left ventricular short-axis views at the levels of mitral annulus,papillary muscle and apex,and apical four-chamber,two-chamber,and long-axis views by using GE Vivid E9 equipment and M5 S probes.Left ventricular end diastolic dimension(LVEDD),left ventricular apical maximum wall tickness(LVAMWT),left ventricular posterior wall thickness(LVPWT),left atrial end systolic dimension(LAESD),left atrial end systolic volume(LAESV),left ventricular end diastolic volume(LVEDV),left ventricular end systolic volume(LVESV),left ventricular ejection fraction(LVEF),early diastolic mitral flow velocity peak(E peak),late diastolic mitral flow velocity peak(A peak),left ventricular septum of mitral annular motion velocities(Septe’)and left ventricular lateral wall of mitral annular motion velocities(Late’)were obtained by two-dimensional echocardiography and calculated the E/A and E/e’.The global and regional peak systolic subendocardial,mid-myocardial,subepicardial longitudinal strain(LS)and circumferential strain(CS)were measured by the offline Echo PAC 113 software.Calculating the transmural gradient of global and regional longitudinal strain(△LS),the transmural gradient of global and regional circumferential strain(△CS).Results:1.The left ventricular global peak systolic longitudinal strain and circumferential strain reduced from subendocardial myocardium,mid-myocardium and subepicardial myocardium in patients with ApHCM and the control group(P<0.001).The global peak systolic longitudinal strain in subendocardial myocardium,mid-myocardium and subepicardial myocardium as well as the peak systolic total longitudinal strain were significant lower than those in the patients with ApHCM and in the control group(P<0.001).The global peak systolic circumferential strain in mid-myocardium and subepicardial myocardium as well as the global peak systolic circumferential strain in total were significant lower in patients with ApHCM than in the control group(P<0.001).However,the global peak systolic circumferential strain in subendocardial myocardium was no statistical differences between the two groups.2.The peak systolic longitudinal and circumferential strain reduced from subendocardial myocardium,mid-myocardium and subepicardial myocardium at the level of basal,middle and apex segments in patients with ApHCM and in the control group(P<0.001).The peak systolic longitudinal strain in three layers myocardium were lower at the level of basal,middle and apex segment in patients with ApHCM than in the control group.The peak systolic circumferential strain in subepicardial myocardium at the level of basal segment,the peak systolic circumferential strain in mid-myocardium and subepicardial myocardium at the level of middle and apex segments were lower in patients with ApHCM than in the control group.3.The transmural gradient of systolic longitudinal strain increased from the level of basal,middle to the apex segment(P<0.001).Hower,the transmural gradient of systolic circumferential strain were no statistical differences from the level of basal,middle to the apex segment.The transmural gradient of global longitudinal strain and the transmural gradient of longitudinal strain at the level of apex segment were significant higher in the patients with ApHCM than in the control group(P<0.001).The transmural gradient of global and regional circumferential strain were no significantly statistical differences between the two groups(P<0.05).4.The absolute value of global peak systolic longitudinal strain in three layers and in total myocardium as well as the global peak systolic circumferential strain in subepicardial myocardium in patients with ApHCM were negatively correlated with left ventricular apical maximum wall thickness(r=-0.563,P=0.010;r=-0.608,P=0.004;r=-0.496,P=0.026;r=-0.561,P=0.010;r=-0.485,P=0.030).The absolute value of the peak systolic longitudinal strain in mid-myocardium and subepicardial myocardium at the level of apical as well as the peak systolic circumferential strain in subepicardial myocardium at the level of apical were negatively correlated with left ventricular apical maximum wall thickness(r=-0.531,P=0.016;r=-0.547,P=0.012;r=-0.514,P=0.02).Conclusions:1.In patients with ApHCM,the left ventricular strain in three layers were lower,especially in the subepicardial myocardium at the level of apex segment.The left ventricular strain were correlated with left ventricular wall thickness.2.The transmural gradient was increased at the level of apex while lower at the other segments in patients with ApHCM.