Skewness of instantaneous mitral transannular flow-velocity profiles in normal humans
Kupari, M.; Järvinen, V.; Poutanen, V.P.; Hekali, P.
American Journal of Physiology 268(3 Pt 2): H1232-H1238
1995
ISSN/ISBN: 0002-9513 PMID: 7900877 Document Number: 454500
The spatial distribution of instantaneous diastolic flow velocities across the mitral annulus was studied with cardiac gated cine magnetic resonance imaging in 10 healthy persons aged 26-46 yr. Velocity encoding used two interleaved gradient echo pulse sequences with velocity sensitivity in the direction of flow perpendicular to the annular imaging plane. Velocity maps were reconstructed at 30- to 43-ms intervals throughout diastole. Velocity-time curves and mean flow rates were determined in five regions of the mitral annulus using a 0.6-cm-2 measurement area. The spatial velocity minimum was consistently in the anterolateral commissural area, whereas the maximum was in the anterior annulus in early diastole shifting posteromedially in late diastole. The mean flow rate (+-SD) averaged 18.4 +- 8.1 ml cntdot s-1 cntdot cm-2 of annular area centrally, 18.3 +- 7.2 ml cntdot s-1 cntdot cm-2 anteriorly, 16.9 +- 7.4 ml cntdot s-1 cntdot cm-2 posteriorly, 13.0 +- 7.7 ml cntdot s-1 cntdot cm-2 in the anterolateral commissural area, and 23.0 +- 7.3 ml cntdot s-1 cntdot cm-2 in the posteromedial commissural area (P lt 0.001). We conclude that mitral transannular flow shows marked spatial inhomogeneity in normal humans. The skewness of flow profiles compromises the use of local velocity measurements as indexes of left ventricular filling.