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Diastolic flow pattern in the normal left ventricle
O Rodevand1, R Bjornerheim, T Edvardsen
1Medical Department B, Section of Cardiology, the National Hospital-Rikshospitalet, University of Oslo, Norway.
Insights
Normal left ventricle diastolic filling begins with fluid motion towards the apex, followed by vortex formation. This vortex explains retrograde flow in the outflow tract during diastasis.
Area of Science:
- Cardiovascular physiology
- Echocardiography
- Hemodynamics
Background:
- Basally directed (retrograde) velocities are observed in the left ventricular outflow tract during filling.
- These velocities may result from apical blood return or basal shortcuts.
Purpose of the Study:
- To elucidate the diastolic flow pattern within a normal left ventricle.
- To understand the mechanisms behind retrograde velocities during ventricular filling.
Main Methods:
- Utilized high frame-rate 2D color Doppler and color M-mode Doppler echocardiography in 18 healthy adults.
- Measured intraventricular velocities at three levels in inflow and outflow compartments using pulsed Doppler.
Main Results:
- Initially, all velocities were directed apically during early transmitral flow acceleration.
- Retrograde velocities appeared in the outflow tract after peak inflow velocities and during diastasis.
- Retrograde velocities were higher and occurred earlier near the anterior mitral leaflet tip compared to apical levels, indicating early vortex formation.
Conclusions:
- Identified uniform diastolic flow patterns in normal left ventricles.
- Early and late diastolic filling involve initial fluid column motion followed by vortex formation.
- Vortex formation in the left ventricle explains the observed retrograde flow in the outflow compartment.
Objectives:
This study sought to clarify the diastolic flow pattern in the normal left ventricle.
Background:
During left ventricular filling, basally directed (retrograde) velocities are seen in the outflow compartment. These velocities may represent blood returned from the apical region or a shortcut at a more basal level.
Methods:
Left ventricular flow patterns were identified in 18 healthy individuals (age 47 +/- 12 years) with the use of high frame-rate two-dimensional color Doppler and color M-mode Doppler echocardiography techniques. Intraventricular velocities were measured with single pulsed Doppler at 3 levels in both inflow and outflow compartments (posterolateral and anteroseptal parts of the left ventricle).
Results:
During early transmitral flow acceleration, all intraventricular velocities were directed towards the apex. However, after peak early and late inflow velocities and during diastasis, retrograde velocities were identified in the outflow compartment. These retrograde velocities occurred earlier, and were higher, at the level of the deflected anterior mitral leaflet tip compared with more apical levels (P <.001). A velocity pattern was established, consistent with early intraventricular vortex formation behind both 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 left ventricles. The findings suggest that both early and late diastolic filling start with an initial motion of a fluid column, succeeded by vortex formation, which explains retrograde flow in the outflow compartment.