We examined the relationship between trans-mitral blood flow velocity and left ventricular volume in normal and hypertrophied hearts using cross-sectional Doppler echocardiography. We studied 10 normal subjects and 19 patients with left ventricular hypertrophy, 9 with aortic stenosis and 10 with dilated cardiomyopathy. Trans-mitral Doppler flow velocity signals and cross-sectional echocardiograms of the left ventricular short and long axes were digitized in each patient to obtain instantaneous mitral flow velocity, instantaneous left ventricular volume, left ventricular mass, and left ventricular mass/volume ratio at end-diastole. Peak velocities during rapid filling (E wave) were similar in all three groups. Peak velocities during atrial systole (A wave) were significantly increased in aortic stenosis, (124 +/- 28 cm/sec); but were not different from normal in dilated cardiomyopathy (43 +/- 20 cm/sec versus 32 +/- 9 cm/sec). The peak A/E velocity ratio was elevated in aortic stenosis 1.47 +/- 0.30, but in dilated cardiomyopathy it was similar to normal hearts (0.47 +/- 0.23 versus 0.54 +/- 0.15). The percentages of left ventricular filling achieved at the time of the peak E wave, the end of rapid filling, and at the time of the peak A wave were similar in all three patient groups. There was no correlation between blood flow velocities at peak E wave, peak A wave or the A/E velocity ratio and left ventricular volume or mass. There was a significant correlation between peak A velocities and left ventricular muscle/cavity areas (r = 0.81; P less than 0.001). There was a similarly close correlation between the peak A/E velocity ratios and left ventricular muscle/cavity areas (r = 0.80; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)