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 RESULTS: None of the MA dimensions (MAA-D: 7.07±2.20 CONCLUSIONS: MME-derived MAPSE and 3DSTE-derived MA dimensions and derived functional 'sphincter-like' properties are not associated in healthy adults.