Study on the characteristics of mitral annular displacement in middle and late pregnancy fetuses based on speckle tracking imaging / 中华超声影像学杂志

ABSTRACT

Objective To assess the longitudinal mitral annular plane systolic excursion ( M APSE) of different directions in normal fetuses during mid‐late pregnancy based on two‐dimensional speckle tracking imaging ( ST I) . Methods Seventy‐six normal fetuses during middle and late pregnancy were selected at 26－32 weeks of gestation . T he peak M APSE was measured by free angle M‐mode echocardiography ( FAM ) perpendicular to the lateral annulus in the mitral annular plane . The time‐displacement curves of interventricular septal mitral annulus in three different directions including points A ,B and C through transverse level of apex were recorded by STI . T he peak M APSE of interventricular septal mitral annulus ( SEPT‐M APSE‐A ,SEPT‐M APSE‐B ,SEPT‐M APSE‐C) in three different directions including points A ,B and C and the time to peak ( T T P :SEPT‐T T P‐A ,SEPT‐T T P‐B ,SEPT‐T T P‐C) were recorded respectively . T he time‐displacement curves of lateral mitral annulus in three different directions including points A ,B and C through transverse level of apex were recorded by STI . T he peak M APSE of lateral mitral annulus ( LAT‐M APSE‐A ,LAT‐MAPSE‐B ,LAT‐MAPSE‐C) in three different directions including points A ,B and C ,the time to peak( LA T‐T T P‐A ,LA T‐T T P‐B ,LA T‐T T P‐C) were recorded respectively . Finally ,the data were analyzed statistically . Results T he peak M APSE of the lateral mitral annulus in 3 different directions including points A ,B and C[ LA T‐M APSE‐A ( 3 .62 ± 1 .01) mm ,LA T‐M APSE‐B ( 3 .95 ± 1 .04) mm ,LAT‐M APSE‐C ( 4 .45 ± 1 .05) mm ] were greater than those of the interventricular septum mitral annulus[ SEPT‐MAPSE‐A (3 .41 ± 0 .63)mm ,SEPT‐MAPSE‐B (3 .07 ± 0 .50) mm ,SEPT‐MAPSE‐C (2 .82 ± 0 .51) mm] . LAT‐M APSE‐C and SEPT‐M APSE‐A were the largest longitudinal excursions of mitral annulus . T he differences were statistically significant in points B and C ( P ＜0 .05) . T here was no significant difference in point A ( P ＞0 .05) . LA T‐M APSE‐C was less than FAM‐M APSE [ ( 6 .06 ± 1 .35 ) mm ] . T here was a significant difference between them ( P ＜0 .05 ) . Strong correlation was found between them ( r ＝0 .896 , P＜0 .05) . T here were no significant differences in the time to peak of interventricular septal mitral annulus [ SEPT‐T T P‐A ( 0 .210 ± 0 .008 ) s ,SEPT‐T T P‐B ( 0 .213 ± 0 .008 ) s ,SEPT‐T T P‐C ( 0 .210 ± 0 .005 ) s] in directions including points A ,B ,C ( P＞ 0 .05 ) . T here were no significant differences in time to peak of lateral mitral annulus [ LAT‐T T P‐A ( 0 .210 ± 0 .008 ) s , LAT‐T T P‐B ( 0 .213 ± 0 .006 ) s , LAT‐T T P‐C ( 0 .210 ± 0 .007) s] in directions inclucling points A ,B ,C ( P ＞0 .05) . Conclusions Longitudinal systolic motion of fetal left ventricular wall during mid‐late pregnancy has good synchronization . Longitudinal motion of fetal mitral annulus is a comprehensive movement of multiple directions and different degrees of displacement ,with the movement perpendicular to the annulus as the maximum displacement direction . T he displacement parameters of mitral annulus measured by ST I can reflect the left ventricular longitudinal systolic function and have clinical application value in evaluating the left ventricular longitudinal systolic function of fetuses .