This study was performed to evaluate diastolic and systolic flow parameters in patients with hypertrophic cardiomyopathy as assessed by Doppler echocardiography. We examined 45 patients with hypertrophic cardiomyopathy (35 of which had an obstruction) and compared the results of diastolic and systolic measurements with those of two groups of normals (less than 25 years, n = 15; greater than 40 years, n = 10). For the diastolic parameters the isovolumetric relaxation time showed a significant prolongation with 107 +/- 23 ms as compared to normals (greater than 40 years) with 86 +/- 10 ms. No differences were found for the time-to-peak velocity in early diastole. The ratio of the time-velocity-integrals of early and late diastolic filling (E/A) with 2.4 +/- 1.3 was significantly lower as compared to young normals with 4.0 +/- 1.9 but not for the group of normals greater than 40 years with 2.5 +/- 1.0. The time-to-peak velocity in systole (TPVS) of the left ventricular outflow was prolonged in patients with an intracavitary obstruction, and the ratio of TPVS/LVET significant lower as compared to normals. Pressure gradients measured with Doppler showed good correlations to invasive measurements with an r = 0.88, SEE 28.5 mmHg. In color-coded Doppler echocardiography turbulent flow is portrayed as a color-mosaic. The location of turbulence in the outflow tract as well as an accompanying mitral insufficiency are immediately visible, but color-flow Doppler does not allow for quantifying the degree of an obstruction. Conventional and color-coded Doppler echocardiography is an enhancement of noninvasive diagnostics also in hypertrophic cardiomyopathy with respect to the assessment of pathologically changed systolic and diastolic flow parameters, the localization and quantification of an obstruction and the assessment and semiquantification of an concomitant mitral regurgitation.