Diastolic flow pattern in the normal left ventricle

Objectives: This study sought to clarify the diastolic now pattern in the n ormal left ventricle. Background: During left ventricular filling, basally directed (retrograde) velocities are seen in the outflow compartment. These velocities may repres ent blood returned from the apical region or a shortcut at a more basal lev el. Methods: Left ventricular now patterns were identified in 18 healthy indivi duals (age 47 +/- 12 years) with the use of high frame-rate two-dimensional color Doppler and color M-mode Doppler echocardiography techniques. Intrav entricular velocities were measured with single pulsed Doppler at 3 levels in both inflow and outflow compartments (posterolateral and anteroseptal pa rts of the left ventricle). Results: During early transmitral flow acceleration, all intraventricular v elocities were directed towards the apex. However, after peak early and lat e inflow velocities and during diastasis, retrograde velocities were identi fied in the outflow compartment. These retrograde velocities occurred earli er, and were higher, at the level of the deflected anterior mitral leaflet tip compared with more apical levels (P <.001). A velocity pattern was esta blished, consistent with early intraventricular vortex formation behind bot h mitral leaflets. The vortex adjacent to the anterior leaflet subsequently enlarged to include a major part of the left ventricle. Conclusion: Uniform diastolic flow patterns were identified in the normal l eft ventricles. The findings suggest that both early and late diastolic fil ling start with an initial motion of a fluid column, succeeded by vortex fo rmation, which explains retrograde flow in the outflow compartment.