| BACKGROUNDNoncompaction of the left ventricular myocardium is a congenital cardiomyopathy with familial heredity background probably caused by intrauterine arrest of compaction process during the nomal endomyocardial embryogenesis and is characterized by the appearance of prominent trabeculations and deep intertrabecular recesses .The true prevalence of LVNC remains unclear at present. In observational studies, LVNC has been found in 0.014% to 0.26% of all adults referred to an echo -cardiography laboratory and 3.7% of those with LV dysfunction.This disease can exist alone,named isolated left ventricular non-compaction(IVNC). The main clinical feartures are heart failure,thromboemboli events and arrhythmias.Although heart failure is common in the settings of IVNC, this condition is not always fatal. Reports state that 17–40% of patients with IVNC have preserved LV systolic function at the time of initial diagnosis. Even though with ordinary global LV systolic function, there are also dispute about whether the regional myocardial systolic function in patients with LVNC remains normal, and whether the noncompacted segmengts and compacted segmengts affect the same on left ventricular systolic function. Myocardial deformation play a important role in the asessment of left ventricular systolic function, thus, shown to be a sensitive and specific index of myocardial function .Speckle tracking imaging(STI)is a novel echocardiographic modality which based on tracking of characteristic speckle patterns created by interference of ultrasound beams in the myocardium.STI enables qualitative and quantitative asessment of myocardial deformation indices, provides a noninvasive and accurate means to evaluate parameters of longitudinal,radial,circumferential strain and srain rate, in addition, supposes a new technique to evaluate the global and regional dynamics of heart. This study sought to observe the characteristics of regional myocardial strain by speckle tracking imaging , hopping to provide a new precise method to evaluate regional myocardial function in INVC patients.Part 1. Assessment Of Left Ventricular regional myocardial Systolic Function In Patients With Non-compaction Cardiomopathy by Speckle Tracking ImagingThe purpose of this part is to evaluate the peak value of systolic circumferentia,radial,longitudinal strain about segmental left ventricular by Speckle Tracking Imaging .54 IVNC patients and 28 healthy volunteers were included, 54 patients with IVNC which were divided into two groups with Ejection fraction<50%(n=34) and EF≥50%(n=20). High frame rate two-dimensional images were recorded from the left ventricular short-axis views at the levels of mitral annulus, papillary muscle and the apex as well as apical long axis view of left ventricle, apical 4 chamber view and apical 2 chamber . Segmental peak value of systolic circumferentia,radial,longitudinal strain were recorded .Results :①: Compared with healthy subjects and LVNC(EF≥50%), the peak systolic circumferential strain, radial strain and longitudinal strain of all segments reduced significantlyin patients with IVNC(EF<50%)(P<0.05).②T here were no differences in clinical and traditional echocardiographic characteristics between LVNC (EF≥50% ) and controls(P>0.05),yet the peak systolic circumferential strain (Sc), radial strain (Sr) and longitudinal strain(εS) of myocardium at the level of the papillary muscle and the apex in patients with IVNC reduced significantly in comparison with those of controls(P<0.05).Part 2.Asessment of left ventricular systolic function of noncompacted and compacted myocardium in patients with LVNC by speckle tracking imagingThis part is sought to assess left ventricular systolic function of noncompacted and compacted segmengts in LVNC patient with cardic dysfunction by STI. 34 IVNC patients of EF<50% and 28 healthy volunteers were included, 2D images of three consecutive cardiac cycles at mitral valve, papillary muscle and the apical short-axis views as well as apical long axis view of left ventricle,apical 4 chamber view and apical 2 chamber view were acquired. Segmental peak value of systolic circumferentia,radial,longitudinal strain were obtained and compared with values for 28 controls.Results:①: Compared with healthy subjects, the peak systolic circumferential strain, radial strain and longitudinal strain(εS) of all segments including noncompacted and compacted myocardium at the seme palne reduced significantly in patients with IVNC(P<0.05).②The peak systolic circumferential strain (Sc), radial strain (Sr) and longitudinal strain(εS) of noncompacted myocardium at the level of the papillary muscle and the apex in patients with IVNC reduced significantly in comparison with those of compacted segments at the same plane(P<0.05),while there is no difference in peak systolic Sc, Sr andεbetween tnoncompacted myocardium and compacted segments at the level of mitral annulus in patients with IVNC(P>0.05).③There is a significantly negative correlation between the total number of affected segments and LVEF(r=-0.589,P<0.05),and a significantly positive correlation between the total number of affected segments and LV end-systolic volume (r=0.570,P<0.05),LV end-diastolic volume (r=0.538,P<0.05) in IVNC patient.CONCLUSIONS①T here were no differences in clinical and traditional echocardiographic characteristics between LVNC(EF≥50%) and controls(P>0.05). yet the peak systolic circumferential strain (Sc), radial strain (Sr) and longitudinal strain(εS) of myocardium at the level of the papillary muscle and the apex in patients with IVNC reduced significantly compared with those of controls.②Compared with healthy subjects and LVNC(EF≥50%), the peak systolic circumferential strain, radial strain and longitudinal strain of all segments reduced significantlyin patients with IVNC(EF<50%)(P<0.05).③Compared with healthy subjects, the peak systolic circumferential strain, radial strain and longitudinal strain(εS) of all myocardium segments reduced significantly in patients with IVNC(EF<50%) (P<0.05). The peak systolic circumferential strain (Sc), radial strain (Sr) and longitudinal strain(εS) of noncompacted myocardium at the level of the papillary muscle and the apex in patients with IVNC reduced significantly in comparison with those of compacted myocardium at the same plane(P<0.05)④There is a significantly negative correlation between the total number of affected segments and LVEF(r=-0.589,P<0.05),and a significantly positive correlation between the total number of affected segments and LV end-systolic volume (r=0.570,P<0.05),LV end-diastolic volume (r=0.538,P<0.05) in IVNC patient(EF<50%). |
