Abstract
BACKGROUND: The mitral annulus (MA) is a fibrous ring with a three-dimensional (3D) movement during the cardiac cycle having an up-and-town longitudinal motion and a sphincter-like narrowing-dilating pattern respecting the cardiac cycle. In the clinical practice, the MA plane systolic excursion (MAPSE), a feature of MA longitudinal function, can be assessed by the simple and widely used M-mode echocardiography (MME), while changes of MA dimensions and derived functional properties can be accurately measured by 3D speckle-tracking echocardiography (3DSTE) at the same time. The aim of the present retrospective cohort study was to evaluate the associations between MME-derived MAPSE and 3DSTE-derived MA dimensions in healthy adults for better understanding their physiologic relationship. METHODS: The subject group of 137 consecutive healthy individuals (34.8±12.3 years, 66 males) was classified into subgroups regarding their mean ± standard deviation (SD) of MAPSE and end-diastolic and end-systolic MA diameters (MAA-D and MAA-S, respectively). Cut-offs for MAPSE (11 and 17 mm), MAA-D (5.31 and 9.59 cm(2)) and MAA-S (2.36 and 4.62 cm(2)) were used to create the subgroups of subjects with less than mean - SD, mean and larger than mean + SD. RESULTS: None of the MA dimensions (MAA-D: 7.07±2.20 vs. 7.40±2.03 vs. 8.00±2.34 cm(2), P=non-significant (ns) for all; MAA-S: 3.43±1.04 vs. 3.42±1.11 vs. 3.77±1.21 cm(2), P=ns for all) and derived functional properties differed significantly between the subgroups based on MAPSE. With increasing MAA-D, MAPSE did not change (13.8±2.9 vs. 14.0±2.9 vs. 14.6±3.1 mm, P=ns for all), while other MA dimensions and MA fractional area change showed a parallel increase. With increasing MAA-S, MA dimensions increased, while derived MA functional properties showed a parallel decrease with preserved MAPSE (14.4±2.5 vs. 13.9±2.8 vs. 14.5±3.7 mm, P=ns for all). CONCLUSIONS: MME-derived MAPSE and 3DSTE-derived MA dimensions and derived functional 'sphincter-like' properties are not associated in healthy adults.