The Clinical Research Of The Feasibility To Evaluate The Myocardial Function By Velocity Vector Imaging

Velocity Vector Imaging is a new technology by which to observe theglobal and regional myocardial function. It is based on 2D gray scaleimaging and automatic tracing the myocardium with no angle dependenceto obtain dynamic vector diagram which includes the direction andmagnitude of myocardial motion. Velocity vector imaging is a usefulmethod which can quantitatively assess myocardial velocity, strain andstrain rate in longitudinal, radial and circumferential direction;evaluatethe regional myocardial ejection fraction; observe the 100,75and 50percent of time from R wave to peak of S wave and so on.The purpose of this research was to reveal the range of normal valuesand variation regularity of the myocardial velocity, strain, strain rate, the100,75and 50 percent of time from R wave to peak of S wave in normalsubjects and to indicate that VVI was a useful tool in assessing themyocardial function.The research included three parts:1. The regularity of the velocity, strain and strain rate amongdifferent segments of ventricle in healthy persons. Objective: To disclose the range of normal values and variationregularity of the ventricular myocardial velocity, strain, strain rate innormal subjects by velocity vector imaging. To reveal the correlationbetween the ventricular regional function and the age.Methods: Siemens Sequoia 512 equipment with 4V1c probe and VVIsofeware were used. Thirty five subjects were enrolled in this study. Theapical four-chamber, three-chamber and two-chamber view, parasternalshort-axis view at level of mitral valve,papillary muscle and apex werestored. Each wall was divided to three segments: basal segment, middlesegment and apical segment. The longitudinal and radial velocity, strainand strain rate of each segment were measured. Each segment among thesame wall and among the same segment level of different wall wascompared. Meanwhile the correlation between the ventricular regionalfunction and the age were studied.Results: Ventricular longitudinal peak velocities were significantlydecreasing from basal mid to apical segments. Ventricular longitudinalstrain and strain rate were no significant difference from basal mid toapical segments. No significant difference was found in radial motioncharacteristic of left ventricular (LV), LV longitudinal velocity strain andstrain rate were higher than that of radial. Peak velocity and strain rate ofRV free wall were higher than inferior septum and lateral of LV. Nosignificant difference was found between left ventricular strain and right ventricular strain. Peak systolic velocity and early diastolic velocity wasnegative correlation with age. Peak atrial systolic period velocity waspositive correlation with age.Conclusions: VVI was a useful method which can quantitatively assessventricular regional function. Peak velocities of different segmentschange regularly and age was the most important affect factor.2. The regularity of the velocity, strain and strain rate amongdifferent segments of ventricle in healthy persons.Objective: To reveal the range of normal values and variation regularityof the ventricular myocardial velocity, strain, strain rate in normalsubjects by velocity vector imaging. To observe the correlation betweenthe ventricular regional function and the age.Methods: Siemens Sequoia 512 equipment with 4V1c probe and VVIsofeware were used. Thirty five subjects were enrolled in this study. Theapical four-chamber view was stored. VVI measurements included atrialsystolic velocity, strain and strain rate for the septum, lateral wall and theatrial roof.Results: The atrial velocity, Strain and strain rate velocities weresignificantly decreasing from base to roof. The atrial velocity measured inthe roof position was near to zero. The atrial strain measured in the roofposition was lower than that in the septal and lateral wall, the atrial strainrate measured in the lateral wall was higher than that in the roof position. There was no significant difference of velocity and strain among theseptum, lateral wall and the atrial roof. The right atrial strain rate wasobviously high than the septum wall strain rate.Conclusions: VVI may provide a noninvasive, simple, quantitative andpotential useful tool for atrial systolic function evaluation.3. Assessment of myocardial synchrony in normal subjects byVelocity Vector ImagingObjective: To evaluate inter-ventricular myocardial synchrony in normalsubjects by Velocity Vector Imaging (VVI).Methods: Siemens Sequoia 512 equipment with 4V1c probe and VVIsofeware were used. Thirty-five subjects were enrolled in this study. Theapical four-chamber, three-chamber and two-chamber view, parasternalshort-axis view at level of mitral valve, papillary muscle and apex wereacquired with echocardiographic system. Each wall was divided to threesegments: basal segment, middle segment and apical segment. The100,75and 50 percent of time from R wave to peak of S wave wereobserved and the parameters of each segment were compared.Results: The fifty percent of time from R wave to peak of S wave inapical segments of anterior septum, inferior septum and anterior wallwere all longer than those in basal and mid segments (P＜0.05). Inparasternal short-axis view at level of mitral valve, there were significantdifference in the seventy-five percent of time from R wave to peak of S wave among inferior wall, anterior wall, anterior septumand lateral wall,as well as in fifty percent of time from R wave to peak of S wave.Conclusions: It is important to maintain myocardial synchrony for thecardiac function. VVI can noninvasively, quantitatively, accurately andquickly assess myocardial synchrony.