Instantaneous mitral valve leaflet velocity and its relation to left ventricular wall movement in normal subjects.

Echocardiograms showing mitral valve leaflets, interventricular septum, and posterior wall of the left ventricle simultaneously were recorded at a paper speed of 100 mm/s in 20 normal subjects. These records were manually digitized and a computer was used to derive mitral valve velocity, left ventricular dimension, and its rate of change continuously throughout a single cardiac cycle. The pattern of instantaneous mitral valve velocity with respect to time was similar in all subjects studied, showing a peak opening rate of 400 +/- 60 mm/s (mean +/- 1 SD), and continuously changing velocity throughout the period of mid-diastolic closure. The peak diastolic closure rate was 250 +/- 60 mm/s and thus appreciably higher than average velocities obtained by manually measuring the slope. A close time relation existed between mitral valve and left ventricular wall movement in early diastole. Forward movement of the anterior leaflet began 1 +/- 6 ms after the onset of outward wall movement, and peak velocity was reached 2 +/- 7 ms after the maximum rate of change of dimension. Later, a discontinuity in wall movement at the end of rapid filling preceded a corresponding discontinuity in the mitral valve velocity tracing by 5 +/- 10 ms. The technique, therefore, allows continuous measurement of mitral valve velocity, and demonstrates its close relation to left ventricular wall movement during diastole.