Exploratory Study In The Influence Of Exercise Stress On Left Ventricular Fluid Field By VFM

To evaluate left ventricular fluid field of isovolumetric contraction(S1),rapid ejection(S2),slow ejection(S3),isovolumetric diastole(D1),rapid diastole(D2),slow diastole(D3),atrial systole(D4)of patients at rest and stress stage by vector flow mapping(VFM).To quantitative analyze the energy loss(EL)in the whole left ventricular chamber,the apical,the middle and the basal segment at seven phases,and explore the influence of exercise stress on left ventricular fluid field.Patients suspected coronary heart disease were prospective enrolled,all patients underwent stress echocardiography and coronary angiography.Finally 26 patients with normal results of stress echocardiography and coronary angiography were enrolled.These patients underwent symptom-limited maximal or sub-maximal treadmill exercise stress echocardiography test according to the Bruce protocol.Color Doppler flow images of three cardiac cycle in standard apical three chamber(A3C)view were acquired at rest and stress stage.The original Doppler images were imported into the VFM image post-processing station for fluid field analysis,then the vortex parameters and energy loss were recorded.The vortex number,direction,area,intensity and the energy loss in the whole left ventricle,apical,middle and basal segment were compared before and after exercise stress.The correlation between energy loss and metabolic equivalence(METs)was analyzed.After exercise stress,the number of vortex in rapid diastole(D2)and the number of clockwise vortex in rapid ejection(S2)and atrial systole(D4)were less than rest.There was no significant differences in vortex area before and after exercise stress.The left ventricular vortex intensity in atrial systole(D4)was increased after exercise stress.The whole left ventricular energy loss in slow ejection(S3),isovolumetric diastole(D1),slow diastole(D3),and atrial systolic(D4)at stress stage were more than rest.The energy loss of left ventricular apical segment in isovolumetric contraction(S1),rapid ejection(S2),slow ejection(S3),isovolumetric diastole(D1),slow diastole(D3),and atrial systole(D4)at stress stage were more than rest.The energy loss of left ventricular middle segment in isovolumetric contraction(S1),slow ejection(S3),isovolumetric diastole(D1),slow diastole(D3),and atrial systole(D4)at stress stage were more than rest.The energy loss of left ventricular basal segment in slow diastole(D3)at stress stage was more than rest.The whole left ventricular energy loss in rapid diastole(D2)and slow diastole(D3)at stress stage were negatively correlated with metabolic equivalent(METs),and the correlation coefficients were-0.535(p=0.006),-0.545(p = 0.005),respectively.The energy loss of left ventricular apical segment in slow diastole(D3)at stress stage was negatively correlated with METs,r =-0.447(p = 0.006).The energy loss of left ventricular middle segment in slow diastole(D3)at stress stage was negatively correlated with METs,r=-0.442(p=0.031).There was no significant correlation between energy loss and METs at rest and stress stage in left ventricular basal segment.After exercise stress the blood flow in left ventricle was disorder,the vortex shape was not as regular as rest,and there was no significantly change of the vortex area.The vortex intensity in atrial systole(D4)was increased.After exercise stress,the energy loss of the left ventricle in apical and middle segment were increased.The higher the METs,the lower the energy loss,and the better the stability of the left intra-ventricular fluid flow in rapid diastole(D2)and slow diastole(D3)at the stress stage.