Transmitral diastolic inflow velocities determined by Doppler echocardiography have been shown to reflect left ventricular (LV) filling rates, and are therefore dependent on ventricular compliance. Radius to wall thickness ratio is an index of cavity to wall volume ratio, an important determinant of LV compliance. Accordingly, Doppler measurements of mitral anulus peak early diastolic velocity, peak atrial velocity and atrial filling fraction were made in 25 normal control subjects, mean age 46 years (range 28 to 75), and 29 patients with dilated cardiomyopathy or concentric LV hypertrophy, mean age 54 years (range 12 to 78). In addition, radius/thickness ratio was determined by 2-dimensionally guided M-mode recordings of the left ventricle. In the normal group, peak early velocity, the ratio of early to atrial velocity and atrial filling fraction correlated with age (r = -0.905, -0.823 and 0.810, respectively), but not with radius/thickness ratio. In the group with LV hypertrophy or dilatation, peak early velocity, ratio of early to atrial velocity and atrial filling fraction correlated with radius/thickness ratio (r = 0.625, 0.752 and -0.631, respectively), but not with age. Thus, with normal aging, early LV filling is reduced and atrial systole is augmented, probably reflecting intrinsic alterations in myocardial stiffness with age. In chronic LV disease, changes in radius/thickness ratio and, consequently, in chamber stiffness, influence early filling directly and atrial filling inversely, overriding the effects of age. Age-related standards are needed, however, to evaluate individual effects of a disease process on LV filling dynamics by Doppler.