Evaluation Of Left Ventricular Wall Motion Using Velocity Vector Imaging In Normal Subjects And Patients With Coronary Heart Disease Before And After Percutaneous Coronary Intervention Therapy

Objective Using Velocity Vector Imaging(VVI) to assess the characteristic of left ventricular(LV) regional myocardial motion and twist motion of health person and analyze LV regional and global myocardial function in patients with coronary artery diseases(CAD) and their changes after percutaneous coronary intervention(PCI).Material and Methods Thirty six healthy adults and twenty two patients with CAD were enrolled in this study.Two-dimensional dynamic images of standard apical four-chambers,two-chambers, long-axis views and parasternal short-axis views at the level of mitral valve, papillary muscle and apex were obtained in VVI condition.All patients were examined before 1 day before PCI,1 week,1 month and 3 months after PCI respectively.Each wall was divided to three segments:basal segment,middle segment and apical segment.Using the off-line syngo US workplace software,the longitudinal and radial systolic peak velocity,displacement,strain,strain rate,circumferential strain,strain rate and segmental ejection fraction of each segment were measured as regional motion condition and LV rotation degree,rotation velocity at baseline and apex,twist and torsion were analyzed as global motion condition.Results (1)There is a certain rule in LV wall motion in normal subjects :①Longitudinal parameters at basal segments were higher than those at middle segments and apical segments.Radial parameters at middle segments were higher than those at basal segments and apical segments.Compared with basal segments and middle segments,circumferential parameters at apical segments were highest.Peak strain and strain rate at LV free wall were lower than those at ventricular septum.②Rotation degree,rotation velocity at basal and apical level of LV were regular changed with the cardiac cycle;the rotation direction was clockwise at the baseline and counterclockwise at the apex,and is combined to yield a systolic counterclockwise twisting as seen from apex to baseline.Significant correlation was found between LV twist degree and age,correlation coefficient of peak LV twist,torsion with age is 0.41,0.53 respectively.LV apex rotation degree,systolic rotation velocity and peak LV twist degree at old-age group were significant higher than those at young-group and middle-age group.At young-age group and old-age group,rotation degree at apex is higher than that at baseline.(2)Most parameters of myocardial systolic motion decrease significantly when coronary artery stenosis≥50% and abnormal longitudinal parameters of myocardial systolic motion appear early while coronary artery stenosis.As stenosis,longitudinal strain and strain rate of ischemic myocardium have a bidirectional change:decreased first,then increased and decreased at last.(3)After PCI, regional systolic function of ischemic myocardium at 3 group improved gradually; regional systolic function at 4 group increased in a short term and decreased afterward.Regional systolic function of normal and slightly ischemic myocardium at 0,1 and 2 group also showed some improvement after therapy.(4)LV ejection fraction and peak torsion at myocardial infarction group were lower than those at normal control and myocardial ischemia group.Compared with peak twist,peak LV torsion can preferably reflect a real condition of LV global systolic function in patients with myocardial infarction.In myocardial infarction group and myocardial ischemia group,changes of LV apex rotation degree and velocity,peak twist and peak torsion after coronary artery recanalization were opposite:those parameters of the former increased 1 week or 1 month after PCI but decreased 3 months after PCI while those of the latter decreased 1 week after PCI but increased gradually 1 month and 3 months after PCI.Conclusions VVI technique was a useful method which can quantitatively assess ventricular regional longitudinal,radial and circumferential motion and global twist motion,so it can evaluate ischemic myocardial regional function and ventricular global function in patients with CAD before and after PCI comprehensively, three-dimensionally and objectively and then provide the important objective basis for the clinical diagnosis of CAD and treatment perscription after PCI.