Study Of Velocity Vector Imaging In The Evaluation Of Left Ventricular Diastolic Function

Objective: The aim of this study was to determine the utility of Velocity Vector Imaging(VVI) in the evaluation of left ventricular diastolic function .Methods: According peak velocity of the mitral inflow , peak velocity of pulmonary venous flow and left ventricular ejection fraction(EF),the patients with E/A<1 and EF>50% defined as case group (diastolic dysfunction ),28 control subjects with 11and EF>50% defined as control group (normal diastolic function). Firstly, linking the electrocardiogram, All subjects underwent conventional echocardiography examination and E ,A,Adur,E/A, deceleration time of E(DT),left atrial (LA) diameter ,thickness of IVS and LVWP EF and peak velocity(S,D,AR) of pulmonary venous flow and were measured .Secondly ,starting the VVI pattern, two dimensional dynamic images of three standard apical views and three short views were collected with a frame rate >70 frames per second under 1 beat and 2 beat conditions of acoustics acquisition. All 2-dimensional dynamic images were stored digitally and analyzed off-line with syngo Velocity Vector Imaging software (Axius, Siemens Medical Solutions USA, Inc.). The endocardial border of the left ventricle was traced manually and automatically tracked by the software. Peak early and late diastolic myocardial velocities (Ve,Va,)and Strain rate(SRe,SRa) were recorded for each segment. We compared each segment of case group and control group in Ve,Va,Ve/Va, SRe,SRa,SRe/SRa to know if there was statistical difference and analyse their distribution characteristics in each group. Statistical analyses were conducted using SPSS 11.5 for windows. Data are expressed as mean values±SD.Differences between groups were tested with independent-samples t test. Comparisons among different segments in a group were made by using the one-way ANOVA,comparisons between multi-sample mean and one-sample mean were made by LSD-t and Games-Howell test. Correlation analysis used Spearman correlation. Proportions were calculated with the crosstabs test, specificity and sensitivity was analysed by ROC curve. Results:①Early and late diastolic myocardial velocities of each left ventricular wall of control group and case group were greatest at the base and lowest at the apex cordis in the apical views②Early and late diastolic myocardial velocities among different walls of two groups at the free walls were greater than septal walls at the same level.③Early and late diastolic myocardial strain rate of control group were greatest at the apex cordis.④Early diastolic myocardial velocities of control group were greater than those of case group at the basal and the mid segments. Ve/Va values of control group were greater than those of case group at the base and mid segments. Ve/Va values between two groups were variable in the apex at the apical views, Ve/Va values of segments in the control group were mostly greater than theirs of case group at the short views.⑤At the apical views SRe in the control group were greater than case group, SRe/SRa in the control group were greater than case group. SRe/SRa values of control group were greater than those of case group in the apex at the short views(p<0.01).⑥The proportion of segments with Ve/Va<1 in the case group were greater than those of conrol group,the proportion of segments with SRe/SRa<1 in the case group were much greater than those of control group(p<0.001).⑦There were positive correlation between SRe and SRe/SRa of most segments in the control group and case group at the apical views.Conclusion:①Early and late diastolic myocardial velocities of each left ventricular wall in contol group are changing regularly: Early and late diastolic myocardial velocities of each left ventricular wall of control group are greatest at the base and lowest at the apex cordis from the apical views; Early and late diastolic myocardial velocities among different walls of control group at the free walls are greater than septal walls at the same level.②Early and late diastolic myocardial strain rate of control group at the apex cordis are greater than basal and mid part of left ventricular .③V VI index (Ve/Va,SRe,SRe/SRa)can evaluate left ventricular diastolic function.④Ve/Va<1 might be suitable for evaluating left ventricular diastolic function of basal and mid segments and SRe/SRa<1 might be suitable for evaluating left ventricular diastolic function of apical segments.⑤VVI index not only can evaluate regional left ventricular diastolic function but also global left ventricular diastolic function.