In order to study the mitral cusp pliability and calcification "in vivo" on the basis of the difference in the maximal and effective valve area, the Doppler-echocardiographic and computer tomographic method was used. The cusp pliability on the basis of the difference between the maximal and effective mitral valve area in absolute measures of cm2 was significantly smaller in patients with mitral stenosis, but in the deviations from normal indexed values of cusp pliability excluding the influence of the anatomic or maximal orifice area, there were no significant differences (normal values 0.00 +/- 27%). The normal relationship of the difference between the maximal and effective mitral valve area in absolute measures (y = cm2) and the maximal mitral valve area (x = cm2) is formulated with the regression equation: y = 0.317x - 0.245. The linear correlation of the normal mitral valve area and the stroke volume at rest in patients with the normal mitral valve is very tight. The stroke volume is significantly lower in mitral stenosis, and the time-velocity integral in the diastole or the mitral stroke distance was significantly greater. The relationship of the percentual deviation from the normal indexed values of cusp pliability excluding the influence of the anatomic or maximal orifice area, on the one hand, and the computer-tomographic approximation of calcium incrustation in mitral leaflets on the other are defined with a tight linear correlation. One could conclude that the magnitude of cusp pliability or calcification can be approximated by the Doppler-echocardiographic method.