Evaluation Of Left Ventricular Systolic Synchronicity In Patients With Aortic Stenosis Application Using Real-time Three-dimensional Echocardiography And Velocity Vector Imaging

Objective:The real-time three-dimensional echocardiography(RT-3DE) and velocity vector imaging (VVI) technology were used for thedetection of left ventricular systolic synchronization of segmental volumes andmyocardial strain in normal subjects and dysynchronization in patients withaortic stenosis (AS), to establish the correlation between left ventricular systolicmechanical function and volume changes. Materials and Methods:1. GeneralInformation: The experimental group contained28cases of aortic stenosispatients, including16males and12females, aged from37to62years old; themean age was50±8.3years old. The normal control group contained36casesof age-matched healthy volunteers, including20males and16females, agedfrom35to67years old; the mean age was51±9.5years old.2. ImageAcquisition: The real-time three-dimensional echocardiography was carried outin all patients by using the SIEMENS ACUSON SC2000color Dopplerultrasound system equipped with4Z1c type of probe, with the transmittingfrequency of2.8MHz for collection of the real-time three-dimensionalechocardiography images. The left ventricular three-dimensional full-volumeimages were collected in three consecutive cardiac cycles and analyzed usingthe LVA analysis software. The system automatically recognized theendocardial border and calculated the left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricularejection fraction (LVEF) and17-segment systolic dyssynchrony index (SDI).The resulting data were all corrected by the heart rate and expressed as thepercentage of cardiac cycle. LVEDV, LVESV and LVEF were all the evaluationindexes of left ventricular systolic function, and SDI was the evaluation indexof left ventricular systolic synchrony. The velocity vector imaging was used tocollect the real-time dynamic two-dimensional gray-scale images of standardshort axial sections at mitral valve level, papillary muscle level and apex leveland long axial sections of apical four-chamber, two-chamber and three-chamberof the left ventricle from all subjects during three consecutive complete cardiaccycles by using the SIEMENS ACUSON SC2000ultrasound system equippedwith4V1type of probe, with the transmitting frequency of2.0-4.21MHz. Theimage data were all input into VVI ultrasound workstation. The left ventricularlong axial section of the apex was extracted for measurement of the time tosystole peak from the longitudinal velocity vector (Tvl), and the parasternalshort axial section was extracted for measurement of the time to systole peakfrom the radial velocity vector (Tvr) and circumferential strain (Tsc). Thestandard deviations of Tvl, Tvr and Tsc (Tvl-SD, Tvr-SD and Tsc-SD) at18segments and the differences of the largest time to peak between any twosegments (Tvl-dif, Tvr-dif and Tsc-dif) in the left ventricle were calculated andconsidered as the longitudinal, radial and circumferential dyssynchrony indexesof left ventricular myocardium. Results:1.There were no statisticallysignificant differences in general conditions including age, weight and heart rate between two groups.2.Comparison of RT-3DE parameters: There werestatistically significant differences in LVEDV, LVESV, LVEF and SDI betweentwo groups. SDI was positive correlated to LVEF (r=-0.678,P<0.05).3.Comparison of VVI parameters: The results of comparative analysis of leftventricular systolic dyssynchrony index including Tvl-SD, Tvr-SD, Tsc-SD,Tvl-dif, Tvr-dif and Tsc-dif between AS group and normal control group were79.23±15.35ms vs31.59±11.10ms；61.13±17.35ms vs32.18±8.48ms；67.28±18.23ms vs57.25±18.92ms；269.04±59.70ms vs104.78±49.10ms；219.00±75.07ms vs100.19±29.57ms；253.11±85.02ms vs213.28±69.02ms,respectively. Compared to the control group, the left ventricular dyssynchronyindexes were all increased, and there were statistically significant differencesbetween various data in AS group (P<0.05).4. A correlation analysis betweenRT-3DE and VVI parameters showed that SDI was positive correlated toTvl-dif, Tvr-dif and Tsc-dif (r=0.551，P<0.01；r=0.431，P<0.05；r=0.510，P<0.01). Conclusion:1. Normal subjects have better overall and segmentalleft ventricular systolic synchrony.2. The left ventricular systolic function wasdecreased with the reduction of left ventricular systolic synchrony in the ASgroup.3. The left ventricular systolic volume dyssynchrony index in RT-3DE inthe AS group was higher than the control group; the left ventricular systolic没myocardial contraction dyssynchrony index in VVI was also higher than thecontrol group. The overall left ventricular systolic dyssynchrony at all segmentsand directions was explored in the AS group.4. RT-3DE and VVI have somerelevance in evaluation of the changes in left ventricular volume and myocardial contraction synchrony, providing valuable information for the earlydiagnosis, evaluation, treatment assessment and prognosis of patients withaortic stenosis associated with left ventricular dysfunction.