A Preliminary Study Of The Structure And Function Of Left Atrium In Patients With Orthostatic Hypotension By Echocardiography

Objective: To assess the structure and function of left atrium in patients with orthostatic hypotension by echocardiography.The analyze the relationship between left atrium volume and left ventricular diastolic function measured by RT-3DE.Material and Method:1.Selected 73 research objects and divided them into two groups as below:(1)The experimental group,namely orthostatic hypotension group is consisted of 43 patients who have been examined in our hospital during January 2016 to November 2017,including 27 males and 16 females.Their ages are 49-77,the average age is(61±9.2),and the ECG is normal sinus rhythm.Selection Standard:(1)Diagnosis standard for postural hypotension of AAN and AAS in 1996: The systolic arterial pressure decreasing is?20mmHg and(or)diastolic pressure decreasing is?10mmHg within 3min from clinostatism to erect position.(2)All selected patients have the medical history of hypotension for ?5 years with the clinical feature of dizziness as the initial symptom.Exclusion Standard:(1)The patient has taken the medicine which can affect the blood pressure recently;(2)The patient has serious psychological disorder or other physical disease,and cannot be cooperated with the measurement of postural hypotension;(3)The patient hasbeen implanted with cardiac pacemaker,or has atrial fibrillation,arrhythmia,multiple system atrophy,serious valvular heart disease and cardiomyopathy;(4)The patient has atherosclerosis or peripheral vascular diseases;(5)Diseases related with inner ear shall be excluded.(2)The normal comparison group has 30 healthy examiners,including 16 males and 14 females.Their average age is(57±8.7),with sinus rhythm,and they are matched with the postural hypotension group in weight,height,age and gender.Selection Standard: The measurement scope of systolic pressure satisfies the standard of(90-139mmHg),the measurement scope of diastolic pressure satisfies the standard of(60-89mmHg),and the systolic arterial pressure decreasing is<20mmHg,diastolic pressure decreasing is<10mmHg.Meanwhile,the blood biochemical analysis results and examination results of clinical and medical science department after the inquiry and analysis of previous history,history of present illness,family medical history and chronic disease history shall be all normal.Instruments and Devices:It adopts the Philips iE33 color doppler ultrasonic diagnosis apparatus,s5-1matrix probe,X5-1 3D probe with the frequency of 1-5MHz.It has the basic function of two-dimensional ultrasonography,M-mode echocardiography and doppler ultrasound.Meanwhile,it is equipped with quantitative analysis software QLAB 9,which can conduct off-line analysis for the collected dynamic image.Research Methods: All research objects will be conducted with transthoracic two-dimensional ultrasonography,M-mode echocardiography,spectral doppler,and tissue doppler echocardiography,and the strain/ strain rate technology(GLS)as well as real-time 3D ultrasonography will be used tomeasure relevant parameters:(1)Normal two-dimensional,doppler and M-mode echocardiography measurement normal parameter: LADa,LADb,LADc,S wave,D wave,Ar wave,IVSTd,LVPWTd,LVIDs,LVIDd,EDV,ESV,LVFS,E peak,A peak,VE/VA,AVTI,TVTI,Ve,Va,after calculation,the LAFF,VE/Ve specific value can be obtained.LVEF is obtained by dual plane Simpson's Method.(2)The software aCMQ is used to measure the left atrium whole long axis strain(GLS).(3)The software 3D-Advanced is used to measure the max volume of left atrium(LAVmax),minimal volume of left atrium(LAVmin),and the volume before the voluntary contraction of left atrium(LAVp),and then obtain the LAVImax,LAVImin,LAVIp,LAEF,LATSV,LAEI,LAASV,LAAEF,LAPEF,LAPSV after calculation.The SPSS22.0 statistics analysis software is used,and the result is shown as ? X ? S.For discrete variable,the proportion is used as the form of expression.The average value comparison of data and materials between different groups uses two independent sample t for test,and(P<0.05)indicates that the difference has statistical significance.The measurement data which is qualified for normal distribution shall be conducted with the Pearson correlation analysis,and(P<0.05)indicates that the difference has statistical significance.Result:1.The difference of normal group and orthostatic hypotension group in gender,height,weight and age has no statistical significance.(P>0.05)2.Size comparison of left atrium by traditional regular ultrasound:Comparing with normal comparison group,the LADa of orthostatic hypotension group is increased obviously,and the difference has statistical significance(P<0.05);LADb,LADc is increased,and the difference has nostatistical significance(P>0.05).Comparison of left atrium function: Storage function of left atrium: S peak is increased,and difference has no statistical significance(P>0.05).Left atrium booster pump function: Comparing with the normal group,the Ar peak and LAFF of postural hypotension group is increased,and the difference has no statistical significance(P>0.05).Left atrium conduction function: Comparing with the normal comparison group: D peak is increased,and the difference has no statistical significance(P>0.05).Comparison of size and structure of left atrium: LVIDs,LVIDd,EDV,ESV,LVPW,IVSTd is higher than the normal group,and the difference has statistical significance(P<0.05);Left atrium diastolic function comparison:Comparing with the normal group,the VE/Ve,VE/VA of postural hypotension group is decreased obviously,and the difference has statistical significance(P<0.05);Left atrium contraction function comparison: Comparing with the normal group,the left atrium LVEF,FS is decreased obviously,and the difference has statistical significance(P<0.05).3.Left atrium mechanical function measured by 2D-STE: GLS of postural hypotension group is lower than the normal comparison group obviously,and the difference has statistical significance(P<0.05).4.Left atrium functional parameter of postural hypotension group measured by RT-3DE: Storage function of left atrium: Comparing with the normal comparison group,the LAVmax,LAVImax,LAVmin,LAVImin,LAVPre,LAVIPre,LATSV is increased obviously,and the difference has statistical significance(P<0.05);LAEI,LAEF is decreased,and the difference has no statistical significance(P>0.05).Left atrium booster pump functional parameter: Comparing with the normal comparison group,the LAAEF,LAASV is increased obviously,and the difference has statistical significance(P<0.05).Left atrium conduction function: Comparing with the normal comparison group,the LAPEF is decreased,the LAPSV is increased,and the difference has no statistical significance(P>0.05).5.LAVmax,LAVmin,LAVpre,LAVImax,LAVImin,LAVIpreA of postural hypotension group measured by RT-3DE is obviously negatively correlated with GLS(r=-0.380,P=0.012;r=-0.471,P=0.001,r=-0.462,P=0.002;r=-0.394,P=0.009;r=-0.483,P=0.001;r=-0.452,P=0.002).6.Each left atrium volume parameter of orthostatic hypotension group LAVmax,LAVmin,LAVpre is positively correlated with E/e'(r=0.406,P=0.008;r=0.436,P=0.004;r=0.565,P=0.000).Conclusion:1.The structure and function changing of left ventricular and left atrium of long term postural hypotension patient is obvious;the left ventricular changing is reflected in left ventricular wall thicken,left ventricular inner diameter increasing,left ventricular end-systole and end-diastolic volume increasing,left ventricular contraction and diastole function decreasing.The left atrium changing is reflected in anteroposterior diameter of left atrium end-systole is increased,left atrium whole strain value is decreased,left atrium storage function and booster pump function is damaged.2.The left atrium volume measured by RT-3DE and the left ventricle diastolic function E/e' has correlation,which is that the left atrium volume of long term postural hypotension patient is increased,left ventricle diastolic function is decreased.Using left atrium volume to evaluate the left ventricle diastolic function can provide a new reference standard for clinical evaluation of left ventricle diastolic function.3.When the left atrium function of postural hypotension patient isevaluated by normal ultrasound,the result changing is not so obvious.However,when the left atrium function is evaluated by strain and real-time3 D ultrasound cardiogram,it founds that the changing is obvious.So it proves that evaluation of left atrium function by advanced method is more sensitive.