Objectives: The aim of this study was to assess the characteristics of mitral annular plane systolic excursion (MAPSE) in different longitudinal directions in normal fetuses using a new method, automatic cardiac motion quantification (aCMQ).
Methods: A cross-sectional study was conducted in 164 fetuses with structurally normal hearts. The time-displacement curves of the septal mitral annulus (SMA) in three directions, including point A, B and C (MAPSE-SMA-A, MAPSE-SMA-B, MAPSE-SMA-C), were recorded by aCMQ. The time to peak (TTP) in three directions, including point A, B and C (TTP-SMA-A, TTP-SMA-B, TTP-SMA-C) were recorded. In the same way, various parameters of the lateral mitral annulus (LMA) were obtained including MAPSE-LMA-A, MAPSE-LMA-B, MAPSE-LMA-C, TTP-LMA-A, TTP-LMA-B and TTP-LMA-C. Free angle M-mode echocardiography (FAM) was used to obtain MAPSE of LMA (FAM-MAPSE). Finally, all the data were analyzed statistically.
Results: MAPSE was positively correlated with gestational age, and the difference between the second- and third-trimester groups was statistically significant. MAPSE-LMA in point B and C were greater than those of SMA. MAPSE-LMA-C and MAPSE-SMA-A were the largest in three directions.The difference between point B and C were statistically significant (p < .05), with no significant difference at point A (p > .05). There was no significant difference found in all TTP (all p > .05). The MAPSE-LMA-C was less than the FAM-MAPSE, and the differences were found significantly (p < .05), but there was better correlation (p < .05).
Conclusions: The longitudinal movement of the fetal mitral annulus is comprehensive, with multiple directions and different displacements. Perpendicular to the mitral annulus is the maximum displacement. It is positively related to the gestational age. From the second trimester, the longitudinal contraction of the left ventricle wall has good synchronization. It possesses clinical value in selecting different methods and parameters during evaluating left ventricular function.
Keywords: Mitral annular plane systolic excursion; automated cardiac motion quantitation; echocardiography; fetus; speckle-tracking.