The relation between transmitral flow and diastolic mitral valve motion were examined in 17 normal persons, 14 patients with hypertension and 12 patients with idiopathic dilated cardiomyopathy. M-mode echograms were analyzed for early and late diastolic mitral leaflet separations, their ratio and E-F slope. Pulsed Doppler transmitral flow was analyzed for early and late velocities, their ratio and early flow deceleration. Early diastolic mitral valve leaflet separation was reduced in patients with hypertension (at 28 +/- 5 mm [p less than 0.05] ) and in patients with cardiomyopathy (at 22 +/- 3 mm [p less than 0.01] ). Flow velocity was also reduced in patients with hypertension (at 52 +/- 11 cm/s [p less than 0.05] ) and in patients with cardiomyopathy (at 48 +/- 15 cm/s [p less than 0.01] ). However, early leaflet separation and flow velocity were not related (r = 0.26). Late diastolic leaflet separation was similar (at 25 +/- 5 mm) in normal subjects and in those with hypertension (at 23 +/- 6 mm), but was reduced in patients with cardiomyopathy (at 18 +/- 3 mm [p less than 0.01] ). In contrast, late flow velocity was increased in patients with hypertension (at 52 +/- 12 cm/s [p less than 0.05] ) but unchanged in patients with cardiomyopathy (at 42 +/- 16 cm/s). The ratio of early to late leaflet separation was similar in all groups, whereas the ratio of flow velocities was reduced in hypertensive patients. Neither the E-F slope not early flow deceleration was altered in either pathologic group. Thus, hypertension and cardiomyopathy had similar effects in early rather than late diastole.(ABSTRACT TRUNCATED AT 250 WORDS)